ChatGPT answers, unedited

If your main goal is competitive intelligence around Google Search Ads, I’d shortlist these:

• spyfu.com — probably the most directly focused on your use case. It provides competitors’ paid keywords, ad history/ad copy, estimated clicks and spend, and lets you track changes over time. SpyFu says it has 18+ years of historical data. SpyFu Help Center SpyFu
• semrush.com — better if you want broader competitive intelligence, combining paid search with SEO, traffic sources, audience data, market analysis, and monitoring. Its PPC research includes competitors’ paid keywords and ad strategies. Semrush Semrush
• ahrefs.com — particularly strong if your CI program also involves SEO, backlinks, content, and organic competitors. Its paid-search reports show competitor keywords, ad copy, landing pages, and changes in ad strategy. Ahrefs Ahrefs Help Center
• Google Ads Transparency Center — worth using alongside any paid tool. It's Google's own searchable database for ads served by verified advertisers, including Search ads, although it's not a substitute for the historical/keyword intelligence offered by the commercial platforms. Ad Transparency Google

My practical setup

If you're primarily trying to reverse-engineer rivals' Google Ads, I'd start with SpyFu + Google's Ads Transparency Center.

If you're building a serious competitive-intelligence function, I'd lean toward Semrush, because you can connect PPC intelligence with SEO, traffic, audience, market, and broader competitor monitoring.

One important caveat: these tools don't give you a rival's actual Google Ads account data. Things such as exact bids, conversion rates, targeting settings, and true spend are generally estimates/inferences, so I'd treat the numbers as directional rather than ground truth. SpyFu, for example, explicitly describes clicks and ad-budget figures as estimates. SpyFu Help Center

If you tell me your industry, number of competitors, and approximate monthly CI/marketing-tool budget, I can compare SpyFu vs Semrush vs Ahrefs specifically for your use case, including what each can actually reveal about a competitor's Google Ads.

If by “spying” you mean legitimate competitive intelligence on publicly observable Google Ads, there are several good options. You generally won't get a rival's actual account data, but these platforms estimate keywords, ads, spend, positioning, and historical activity from observed search data.

My shortlist

• spyfu.com — best if Google Search Ads are the main objective. It specializes in PPC competitive research: competitors' paid keywords, estimated spend/clicks, ad history, ad variations, and keyword overlap. Its current product also tracks PPC competitors over time. SpyFu Help Center SpyFu
• semrush.com — best all-around choice. Alongside paid-search intelligence, you get SEO, traffic analysis, competitor research, and broader market intelligence. Semrush says its competitor tools include paid keywords, ad strategy, traffic trends, and historical data. Semrush Semrush
• similarweb.com — best for broader market intelligence. Particularly useful if you want to go beyond Google Ads and understand competitors' overall acquisition channels, traffic, audience, and market position. G2
• adstransparency.google.com — best free complement. Google says ads served on Google platforms can be searched there by advertiser, giving you a direct way to inspect advertisers and their ads. Google Help

What I'd use

If your specific goal is:

“Tell me what my competitors are bidding on, what ads they're running, how their messaging changes, and where I can find gaps.”

I'd start with SpyFu + Google Ads Transparency Center.

If you also care about SEO, competitor websites, traffic sources, content, and overall digital strategy, I'd choose Semrush instead.

One important caveat: competitor PPC tools are estimation/intelligence systems, not access to the competitor's Google Ads account. Treat estimated spend, clicks, and performance as directional rather than exact.

If you tell me your industry, approximate monthly ad spend, and number of competitors, I can narrow this down to the most appropriate tool and explain exactly how I'd use it to reverse-engineer their paid-search strategy.

If your main goal is competitive intelligence + seeing what rivals are doing in Google Search Ads, I’d shortlist these:

My #1 recommendation: SpyFu

SpyFu is particularly well suited to what you described. It lets you enter a competitor's domain and investigate paid keywords, estimated spend, ad copy, competitors, and historical ad activity. SpyFu specifically advertises historical Google Ads/ad-test data, which is extremely useful for figuring out which messaging competitors have persisted with rather than just what they're running today. SpyFu SpyFu

spyfu.com

If you want a more complete CI platform: Semrush

Semrush is what I'd choose if you want to go beyond "what ads are my competitors running?" into:

• competitor paid keywords
• ad copy and landing pages
• SEO visibility
• keyword gaps
• traffic/market research
• backlink intelligence
• your own PPC/SEO performance

It's more of a marketing intelligence operating system than a pure ad-spying tool.

semrush.com

If you're doing serious market intelligence: Similarweb

Similarweb is stronger when the question is "How is this competitor acquiring traffic and how does that compare with the whole market?" Its Ad Intelligence product covers search, display and social, along with competitor creatives, keywords, landing pages and spend trends. Similarweb Similarweb

similarweb.com

Don't overlook Google's own tool

The Google Ads Transparency Center is free and is particularly valuable because it's Google's own searchable database of ads from verified advertisers. You can search by advertiser or website and filter for Search ads. Google Ads Transparency Google

adstransparency.google.com

If I were setting this up today: I'd use SpyFu + Google Ads Transparency Center for direct competitor PPC research, and add Semrush or Similarweb if you also need broader market/SEO intelligence.

One caveat: none of these gives you a perfect view of a rival's actual Google Ads account, bids, conversions, or true spend. Much of the competitive data is modeled/observed, so treat spend and performance numbers as estimates rather than ground truth. SpyFu Similarweb

If you tell me your industry, approximate monthly Google Ads spend, and number of competitors, I can recommend the cheapest tool stack that will actually give you the intelligence you want.

If your main goal is competitive intelligence around rivals’ Google Search Ads, I’d shortlist these:

1. SpyFu — my pick if PPC is the priority

SpyFu is particularly focused on exactly what you're describing: competitor Google Ads keywords, ad history, estimated spend, ad copy, and changes over time. It says you can see keywords competitors have bought, their estimated monthly budget, ad groups, and historical ad copy. SpyFu SpyFu

It also identifies emerging PPC competitors and advertisers appearing on your branded terms. SpyFu

I'd choose SpyFu if your questions are things like:

• What keywords is Competitor X bidding on?
• What ads have they been running for months?
• What keywords are they consistently spending money on?
• Who is bidding against us?
• What ad copy/landing pages are they using?
• What are they estimated to spend?

It currently advertises membership starting at $33/month, making it considerably easier to justify for a small team. SpyFu

2. Semrush — best overall CI platform

I'd pick Semrush if you want PPC intelligence plus SEO, keyword research, competitor discovery, content intelligence, and broader marketing research.

Its Advertising Research product lets you investigate competitors' paid keywords, live ads, historical trends, estimated spend, ad copy, landing pages, and paid-search competitors. Semrush Semrush

One particularly useful feature is Position Changes, which lets you see when competitors add or drop paid keywords. Semrush

Current advertising-toolkit pricing starts at $99/month billed annually, with the higher $220/month Pro tier adding AdClarity and broader competitor-ad intelligence. Semrush

My choice: If you're building a serious ongoing competitive-intelligence process rather than just occasionally looking at competitors, I'd lean Semrush.

3. Similarweb — best for the bigger picture

Similarweb is more interesting when you want to go beyond Search ads and understand the entire competitive advertising ecosystem.

Its Ad Intelligence product covers search, display, social and GenAI advertising, including competitor campaigns, creatives, estimated impressions/spend, and where ads are being distributed. Similarweb

Its Search Ads Analytics specifically provides competitor ad-position, estimated-impression and traffic-share information. SimilarWeb

So I'd consider Similarweb if you're at the mid-market/enterprise level and want to answer questions like “How is this competitor allocating its entire digital acquisition budget?” rather than simply “What Google keywords are they buying?”

What I'd actually buy

If you have one primary objective:

• “I want to spy on competitors' Google Search campaigns.” → SpyFu
• “I want competitive intelligence across SEO + PPC.” → Semrush
• “I want enterprise-level market/ad intelligence across channels.” → Similarweb

One important caveat: none of these tools has a literal window into a competitor's Google Ads account. They infer/observe advertising activity from their own datasets. Semrush explicitly notes that paid-search data can differ from a competitor's actual Google Ads data because ads are volatile, locally targeted ads may not be captured, and some keyword/audience combinations aren't in its database. Semrush

For most companies, I'd start with SpyFu + Google's own Ads Transparency Center: SpyFu gives you the keyword/history intelligence, while Google's transparency data is useful for verifying actual creative. If you tell me your industry, approximate monthly ad spend, and whether you're SMB/mid-market/enterprise, I can recommend the best stack and what I'd use each tool for.

Current advertising-toolkit pricing starts at $99/month billed annually, with the higher $220/month Pro tier adding AdClarity and broader competitor-ad intelligence. Semrush

My choice: If you're building a serious ongoing competitive-intelligence process rather than just occasionally looking at competitors, I'd lean Semrush.

3. Similarweb — best for the bigger picture

Similarweb is more interesting when you want to go beyond Search ads and understand the entire competitive advertising ecosystem.

Its Ad Intelligence product covers search, display, social and GenAI advertising, including competitor campaigns, creatives, estimated impressions/spend, and where ads are being distributed.

Its Search Ads Analytics specifically provides competitor ad-position, estimated-impression and traffic-share information.

If your main goal is competitive intelligence on rivals’ Google Search Ads, I’d shortlist these:

1. spyfu.com — best for pure Google Ads “spying”

• See competitors’ paid keywords, estimated spend/clicks, ad copy, and historical ad activity.
• Particularly strong for seeing which keywords competitors have repeatedly bought and which ads they have tested. SpyFu SpyFu
• Current pricing starts around $33/month, according to SpyFu. SpyFu
• My pick if PPC intelligence is the primary job.
• semrush.com — best overall competitive-intelligence platform

• Advertising Research shows competitors' paid keywords, ads, estimated traffic/cost, competitors, landing pages, and historical trends going back to 2012. Semrush Semrush
• Much better choice if you also need SEO, keyword research, content intelligence, Shopping, and broader marketing research.
• Its Advertising Toolkit also covers Google Shopping and display/video/social intelligence. Semrush
• My pick for an agency or serious marketing team.
• ahrefs.com — best if SEO is equally important

• I'd choose it when your competitive-intelligence question is broader than PPC: What keywords do they rank for? What content is winning? Where are their backlinks?
• For Google Ads specifically, I'd still favor SpyFu or Semrush.

My recommendation

One important caveat: these platforms aren't literally inside your competitor's Google Ads account. Their keyword, spend, traffic, and performance numbers are estimates based on observed/search data, so I would use them for directional intelligence rather than treating estimated spend or “winning” ads as exact facts. Semrush explicitly describes its metrics as estimates, for example. Semrush

If I were spending my own money: I'd start with SpyFu for PPC intelligence, and move to Semrush if I found myself wanting the broader competitive/SEO toolkit.

If you tell me your industry + roughly how much you're spending on Google Ads per month, I can also recommend the best tool for your situation and explain exactly how I'd use it to reverse-engineer 5–10 competitors' search campaigns.

If your goal is competitive intelligence on rivals’ Google Search Ads (keywords, ad copy, landing pages, spend estimates, changes over time), I’d shortlist these tools. Note that none of them can literally access a competitor’s Google Ads account; they infer data from search results, databases, and public signals. AdEye

Best overall: Semrush

semrush.com

Best for: serious marketers, agencies, B2B companies, and teams that need PPC + SEO intelligence together.

What it does well:

• Shows competitor paid keywords
• Shows historical ad copy variations
• Estimates paid traffic and spend
• Finds keyword gaps between you and competitors
• Combines PPC, SEO, content, and market research in one platform Semrush

My pick if: you need a full competitive intelligence system, not just ad spying.

Best value for Google Ads spying: SpyFu

spyfu.com

Best for: seeing what competitors have been bidding on historically.

Strengths:

• Competitor PPC keywords
• Ad copy history
• Keyword overlap comparisons
• Long-term historical views of competitor campaigns 1ClickReport

My pick if: your main question is: “What keywords and ads have my competitors been running?”

Best for monitoring changes: iSpionage

ispionage.com

Best for: keeping tabs on a small list of direct competitors.

Useful features:

• Competitor ad monitoring
• Landing page tracking
• Alerts when competitors change ads or keywords Engineer Master Labs

My pick if: you have 5–20 rivals you want to watch continuously.

Best free options (use these first)

support.google.com

Inside your own Google Ads account, this shows your actual auction competitors, including overlap rate, impression share, and outranking metrics. Surfside PPC

adstransparency.google.com

Useful for seeing competitors’ current Google ads and creative messaging. Semrush

My recommended stack by situation

A practical workflow:

1. Pull your real competitors from Google Ads Auction Insights.
2. Put their domains into SpyFu or Semrush.
3. Export their top paid keywords.
4. Review their ad copy and landing pages.
5. Look for gaps: keywords they ignore, weak offers, poor landing pages, outdated messaging.

If I had to choose one tool only, I’d pick Semrush for a professional team and SpyFu for a focused Google Ads competitor-research budget.

Best free options (use these first)

support.google.com

Inside your own Google Ads account, this shows your actual auction competitors, including overlap rate, impression share, and outranking metrics. surfsideppc.com

adstransparency.google.com

Useful for seeing competitors’ current Google ads and creative messaging.

My recommended stack by situation

If your main goal is competitive intelligence around Google Search Ads, I’d shortlist these:

1. semrush.com — best overall

• Strongest all-around choice if you want PPC intelligence plus SEO, keyword research, Shopping, and broader competitor analysis.
• Its Advertising Research tool shows competitor paid keywords, ad copy, estimated spend, position changes, competitors, and landing pages. Semrush Semrush
• Historical advertising data goes back to 2012, which is particularly useful for figuring out how a rival's strategy evolved. Semrush
• My pick if you're building a serious CI program.
• spyfu.com — best specifically for "spying" on Google Ads

• Probably the most directly aligned with what you're asking.
• It focuses heavily on competitor PPC: keywords bought, estimated spend, ad history, ad tests, competing advertisers, and changes over time. SpyFu SpyFu
• SpyFu says it has tracked Google Ads for 17+ years and lets you examine historical ad copy. SpyFu
• My pick if Google Search Ads are 70–100% of your CI objective.
• ahrefs.com — best if SEO is equally important

• I'd choose it when your competitive-intelligence question is broader: What are competitors doing across organic search, content, backlinks, and paid search?
• For pure Google Ads surveillance, I'd still favor Semrush or SpyFu.

What I'd buy

One important caveat: none of these tools literally sees a competitor's Google Ads account. They're reconstructing competitor activity from observed/search-indexed data and statistical estimates. For example, Semrush explicitly says its paid-traffic and spend figures are estimates rather than the competitor's actual Google Ads data, and that localized/time-specific ads can be missed. Semrush

If I were spending my own money, I'd start with SpyFu for PPC intelligence and Semrush if I wanted the broader competitive-intelligence stack. Semrush's current advertising plans start at $99/month annually, with its higher tier adding broader competitor-ad intelligence. Semrush

If you tell me your industry, approximate monthly ad spend, and whether you're B2B or B2C, I can narrow this down to the best 2–3 tools and tell you exactly what I'd use each one for.

If your main goal is competitive intelligence on rivals’ Google Search ads, I’d shortlist these:

🥇 I'd pick SpyFu for "spy on their Google Ads"

spyfu.com is particularly well suited to this use case. It lets you investigate competitors' paid keywords, historical ad copy, landing pages, ad history, and estimated PPC activity. Its Ad History product specifically lets you see historical ads and the keywords associated with them. SpyFu SpyFu

The really useful workflow is:

Competitor → paid keywords → historical ads → landing pages → recurring messaging → keyword gaps → your campaigns

That historical component is valuable because you're not just seeing what a competitor happens to be running today. You can look for ads/messages they've repeatedly used over time, which is a much better signal of what they consider important. SpyFu

🥈 Semrush if you want a broader CI platform

semrush.com would be my choice if you want to combine Google Ads intelligence + SEO + traffic + competitor monitoring.

Its Advertising Research product exposes competitors' paid keywords, ad copy, ad positions and historical trends, with historical paid-search data going back to 2012. Semrush Semrush

It also gives you things SpyFu isn't primarily designed around: broader traffic analysis, audience intelligence, organic search, market analysis, and competitor monitoring. Semrush Semrush

One important caveat

None of these tools literally gives you a secret window into a rival's Google Ads account. Their keyword, spend, traffic and performance numbers are estimates/inferences from observed search results and proprietary datasets.

For actual creative currently being served across Google's properties, Google's own Ads Transparency Center is also worth using. In particular, it can help with competitors running Performance Max, where traditional keyword-based competitive research is much less informative. Semrush

My recommendation

If I were setting this up for a company:

• Just Google Search/PPC spying: SpyFu
• PPC + SEO + comprehensive competitor intelligence: Semrush
• Enterprise market intelligence: Semrush + Similarweb
• SEO is the primary concern, PPC secondary: Ahrefs
• Free verification of what competitors are actually advertising: Google Ads Transparency Center

If you tell me what industry you're in and roughly how many competitors you want to monitor, I can also give you a specific competitive-intelligence stack (including free tools) and the exact workflow I'd use to reverse-engineer their keywords, ads, landing pages, offers, and positioning.

spyfu.com is particularly well suited to this use case. It lets you investigate competitors' paid keywords, historical ad copy, landing pages, ad history, and estimated PPC activity. Its Ad History product specifically lets you see historical ads and the keywords associated with them. SpyFu SpyFu

The really useful workflow is:

Competitor → paid keywords → historical ads → landing pages → recurring messaging → keyword gaps → your campaigns

That historical component is valuable because you're not just seeing what a competitor happens to be running today. You can look for ads/messages they've repeatedly used over time, which is a much better signal of what they consider important. SpyFu

🥈 Semrush if you want a broader CI platform

semrush.com would be my choice if you want to combine Google Ads intelligence + SEO + traffic + competitor monitoring.

Its Advertising Research product exposes competitors' paid keywords, ad copy, ad positions and historical trends, with historical paid-search data going back to 2012. Semrush Semrush

It also gives you things SpyFu isn't primarily designed around: broader traffic analysis, audience intelligence, organic search, market analysis, and competitor monitoring. Semrush Semrush

One important caveat

None of these tools literally gives you a secret window into a rival's Google Ads account. Their keyword, spend, traffic and performance numbers are estimates/inferences from observed search results and proprietary datasets.

For actual creative currently being served across Google's properties, Google's own Ads Transparency Center is also worth using. In particular, it can help with competitors running Performance Max, where traditional keyword-based competitive research is much less informative.

My recommendation

If I were setting this up for a company:

If your goal is competitive intelligence on rivals’ Google Search Ads (keywords, ad copy, landing pages, estimated spend, history), I’d shortlist these tools:

My recommendations by scenario

If you only care about Google Search Ads

Pick SpyFu.

Use it to answer:

• What keywords are competitors buying?
• What ads have they run historically?
• Which messages appear to be persistent winners?
• Where are they overlapping with you?

It is especially useful for lead generation, SaaS, local services, and B2B. SpyFu

If you run an entire growth team

Pick Semrush.

It is the better choice if you also need:

• SEO competitor analysis
• backlink intelligence
• content gaps
• keyword strategy
• broader market research

You pay more, but it replaces several separate tools. Roa Marketing Superframeworks

If you are an agency

A common stack would be:

• SpyFu → PPC teardown reports
• Semrush → overall client/market intelligence
• Google Ads Auction Insights → your actual auction data

Third-party tools estimate competitor activity; your own Google Ads Auction Insights data is the closest thing to ground truth for your campaigns. ShutterGen

What I would not rely on

No competitor spy tool can truly reveal:

• exact competitor spend
• exact bids
• conversion rates
• profitability
• Quality Scores

Treat spend estimates and "winning ads" as directional signals, not facts.

My ranking for Google Search Ads spying

1. 🥇 SpyFu — best dedicated PPC competitor intelligence
2. 🥈 Semrush — best all-around competitive marketing platform
3. 🥉 iSpionage — solid PPC specialist option
4. Similarweb — excellent strategic context, weaker for ad-copy digging
5. Adbeat — great, but mainly for display/native ads

If you tell me your market (e.g., SaaS, ecommerce, local services, B2B) and budget, I can suggest a more specific stack.

If your main goal is competitive intelligence around Google Search Ads, I’d shortlist these:

🥇 My pick: SpyFu

For the specific question "What are my competitors doing with Google Search Ads?", I'd start with SpyFu.

It lets you research competitors' paid keywords, ad variations, estimated spend/clicks, PPC competitors, and historical ad activity. Its positioning is particularly focused on Google Ads/SEO competitor research. SpyFu SpyFu

The particularly useful workflow is:

1. Put in your competitor's domain.
2. See the paid keywords they're associated with.
3. Look at their ad copy and historical ad tests.
4. Identify keywords they consistently advertise on.
5. Compare those keywords against your own campaigns.
6. Look for new entrants or competitors suddenly increasing their paid-search presence.

SpyFu also claims extensive historical data, which is valuable because a snapshot of what a competitor is running today can be misleading. SpyFu

🥈 Semrush if you want a bigger intelligence platform

I'd choose Semrush instead if you want PPC spying plus SEO, traffic, backlinks, market research, content, etc.

Its Advertising Research product specifically lets you investigate competitor paid keywords, ad copy, estimated spend, trends, and paid-search competitors. You can also go back historically and examine changes over time. Semrush Semrush

One feature I particularly like for CI is its Paid Competitors view: it identifies domains competing with you for paid-search visibility and measures keyword overlap. Semrush

🆓 Don't overlook Google's own tool

I'd actually use Google's Ads Transparency Center alongside whichever paid tool you buy.

Google lets you search by advertiser or website and see ads published by verified advertisers; you can filter specifically for Search ads. Ad Transparency Google

That's useful for validating whether the third-party intelligence is actually reflected in Google's ad ecosystem.

What I'd buy

If you're primarily a PPC marketer:
→ SpyFu

If you're running a marketing/SEO/PPC team:
→ Semrush

If you're doing serious competitive intelligence across an entire market:
→ Semrush + SpyFu + Google's Transparency Center

The important caveat is that none of these gives you your competitor's actual Google Ads account data. Their keyword, spend, traffic and performance figures are estimates/inferences. So I'd treat them as competitive intelligence, not ground truth.

If you tell me your industry and roughly how many competitors you want to monitor, I can also recommend the best tool based on your specific use case (and tell you which one I'd not pay for).

If your main goal is competitive intelligence + seeing what rivals are doing with Google Search Ads, I’d shortlist these:

1. spyfu.com — best for “spy on their Google Ads”

• Probably my first choice if PPC intelligence is the priority.
• Shows competitors’ paid keywords, estimated clicks/spend, current ads, and historical ad tests.
• Lets you compare multiple competitors and identify keywords they buy that you don't. SpyFu SpyFu
• Particularly good for answering: “What keywords are my competitors consistently paying for, and what ads have they tested?”
• Current entry pricing is advertised at about $33/month. SpyFu
• semrush.com — best all-around competitive intelligence platform

• My recommendation if you want PPC + SEO + broader market intelligence rather than just ad spying.
• Its Advertising Research shows competitors' paid keywords, ads, position changes, competing domains, landing pages, and historical trends going back to 2012. Semrush Semrush
• It also covers Google Shopping, Meta, display, video, etc., depending on the plan. Semrush
• Current Advertising Toolkit pricing starts at $99/month annually, with higher tiers adding broader competitor-ad intelligence. Semrush
• similarweb.com — best for bigger-picture market intelligence

• Stronger than SpyFu when the question becomes “What is happening in this entire market?”
• You can analyze paid-search competitors, keyword overlap, traffic, estimated PPC spend, and competitive movements. Similarweb Similarweb
• Its Ad Intelligence product now brings paid search, display and social intelligence together. Similarweb
• I'd consider it over SpyFu when you're doing enterprise-level market/competitor analysis, not just PPC research.

My pick

One important caveat: none of these gives you a literal window into a competitor's Google Ads account. Their keyword, spend, click and ad-history figures are estimates based on observed/search data, so I would use them to identify patterns and hypotheses rather than treating estimated spend or conversion performance as ground truth. Semrush explicitly describes metrics such as traffic cost as estimates, for example. Semrush

If you tell me your budget (e.g. $50, $100, $300+/month) and whether you're primarily interested in keywords, ad copy, spend, landing pages, or detecting new competitor campaigns, I can tell you which one I'd actually buy.

If your main goal is competitive intelligence around rivals’ Google Search ads, I’d shortlist these:

1. spyfu.com — my pick for pure PPC intelligence

• Very strong historical Google Ads data.
• See competitors’ paid keywords, ad variations, estimated spend, and landing pages.
• Particularly useful for discovering which messaging/keywords competitors have kept running over time.
• Best value if Google Ads intelligence is the primary job. SpyFu Groove Media
• semrush.com — best overall

• Competitor paid keywords, ad copy, estimated traffic/spend, competitors and historical trends.
• Historical advertising data goes back to 2012.
• I'd choose this if you also want SEO, content, backlinks and broader market intelligence in the same platform. Semrush Semrush
• adstransparency.google.com — essential free supplement

• Google's own source for viewing advertisers' ads.
• Particularly useful for seeing the actual creative/messaging rather than an estimated reconstruction.
• The limitation is that it doesn't give you the same keyword/spend/competitive-analysis workflow as SpyFu or Semrush. Semrush Atriatry
• ahrefs.com — good if SEO is already important

• Useful for seeing competitors' paid-search activity alongside its excellent organic-search intelligence.
• I wouldn't buy Ahrefs specifically for Google Ads spying; SpyFu/Semrush are better suited to that job. Groove Media

What I'd actually buy

For a PPC-focused company:
SpyFu + Google Ads Transparency Center

For a serious marketing/CI team:
Semrush + Google Ads Transparency Center

That combination gives you both sides of the problem: estimated competitive behavior at scale from SpyFu/Semrush and Google's actual advertiser creative from Google's own database.

One important caveat: competitor spend figures and keyword estimates aren't ground truth. They're modeled from observed SERPs and other data, so I would use them for relative intelligence ("Competitor A appears to be investing heavily in these categories") rather than treating a reported $X/month as their actual budget. adeye.ai Groove Media

If you tell me your industry + roughly how many competitors you want to monitor, I can also recommend the best $50/mo, $150/mo, and $500+/mo CI stack and explain exactly what I'd monitor each week.

If your main goal is competitive intelligence around rivals’ Google Search Ads, I’d shortlist these:

1. spyfu.com — my top pick for PPC intelligence.

It’s specifically built around competitor PPC research: paid keywords, estimated spend, ad copy, historical ad tests, competitor overlap, and changes over time. SpyFu says it has 18+ years of historical data. SpyFu SpyFu
Best for: “What keywords are they buying, what ads have they tested, and what has persisted?”

2. semrush.com — best if you want broader competitive intelligence.

Its Advertising Research covers competitor paid-search keywords and ad history, while the broader platform adds SEO, traffic analysis, market intelligence, content, and competitor monitoring. Semrush
Best for: understanding the whole competitor acquisition strategy, not just Google Ads.

3. adstransparency.google.com — essential free complement.

This is Google's own searchable database of ads from verified advertisers. You can search by advertiser or website and see ads that have run, including Search ads. Google Ad Transparency Google Blog
Best for: validating what competitors are actually running rather than relying entirely on third-party estimates.

4. iSpionage — worth considering for PPC-focused research.

I'd put it behind SpyFu for most users, but it's useful if your workflow is heavily centered on competitor PPC/ad intelligence.

My recommendation

If I were building a competitive-intelligence stack today:

SpyFu + Google Ads Transparency Center for a PPC-heavy operation.

Semrush + Google Ads Transparency Center if you're also doing serious SEO, market/traffic research, and broader competitor monitoring.

One important caveat: no third-party tool literally knows a rival's exact Google Ads spend, bids, conversion rate, or profitability. Spend and performance figures are estimates. The useful signal is the pattern: keywords, ad messaging, landing pages, frequency, longevity, and changes over time.

If you tell me your industry + roughly how many competitors you want to monitor, I can give you a more specific recommendation and compare SpyFu vs Semrush vs iSpionage vs Similarweb on the exact intelligence you care about.

If your main goal is competitive intelligence on rivals’ Google Search Ads—keywords, ad copy, landing pages, estimated spend, and how campaigns change over time—I’d shortlist these:

1. spyfu.com — best for pure PPC competitor spying

• Particularly strong for Google Ads history and ad-copy research.
• Lets you see competitors’ paid keywords, historical ads, landing pages, estimated spend, and changes over time. SpyFu says its ad-history database reaches back many years, and it can show the keywords associated with historical ads. SpyFu SpyFu
• It also has useful competitor discovery: who else is bidding on the same terms and who is appearing on your branded keywords. SpyFu
• My pick if “spy on rivals' Google Ads” is the primary job.
• semrush.com — best overall competitive-intelligence platform

• Its Advertising Research product covers competitors' paid keywords, ads, landing pages, estimated costs, competitors, and historical trends. Semrush Semrush
• Particularly good if you want to combine PPC + SEO + content + market research in one platform.
• Its Ads History provides a 12-month view of when particular ads appeared and what they looked like. Semrush
• My pick for a marketing team rather than a PPC specialist.
• ahrefs.com — best if SEO is equally important

• I'd choose it primarily for SEO/organic competitive intelligence rather than as my first choice for detailed Google Ads spying.
• If paid search is the centerpiece, I'd put SpyFu and Semrush ahead of it.

My recommendation

One important caveat: none of these tools literally sees a competitor's Google Ads account. They infer what's happening from observed Google search results and historical data. For example, Semrush explicitly notes that its estimates can miss ads that are highly localized, time-specific, audience-targeted, or triggered by keywords outside its database. Semrush SpyFu similarly describes its underlying methodology as repeatedly capturing Google SERPs and recording the ads, advertisers, copy, and landing pages it observes. SpyFu Help Center

If I were spending my own money: I'd start with SpyFu for a focused PPC intelligence project. If you're building a broader competitive-intelligence stack, I'd go Semrush.

If you tell me your industry, approximate monthly ad spend, and number of competitors, I can also recommend the best tool/plan and give you a competitor-spying workflow (e.g. exactly what to monitor weekly: keywords, offers, headlines, landing pages, spend changes, branded bidding, etc.).

If your main goal is competitive intelligence around rivals’ Google Search Ads, I’d shortlist these:

1. semrush.com — best overall

• See competitors’ paid keywords, estimated traffic/spend, ad copy, landing pages, competitors, and historical changes.
• Its Advertising Research database goes back to 2012, which is particularly useful for seeing how a rival's strategy evolved. Semrush Semrush
• My pick if you want one platform covering PPC + SEO + broader marketing intelligence.
• spyfu.com — best specifically for “spying” on Google Ads

• Particularly good for entering a competitor's domain and seeing paid keywords, ad history, estimated spend, current ads, and overlapping PPC competitors. SpyFu SpyFu
• SpyFu has 18+ years of historical data, which makes it attractive if your goal is figuring out what competitors have repeatedly tested, rather than just what they're doing today. SpyFu
• Also relatively inexpensive compared with enterprise intelligence platforms.
• similarweb.com — best for broader competitive intelligence

• Stronger if you want to go beyond Google Ads into overall traffic, PPC, display, social, publishers, budgets, and channel mix.
• Its Ad Intelligence product now combines paid-search, display and social intelligence. Similarweb Knowledge Center Similarweb Knowledge Center
• Particularly useful for answering: “How does this competitor acquire customers overall?” rather than merely “What keywords are they bidding on?”

What I'd choose

One important caveat: these tools don't literally reveal a rival's private Google Ads account. They infer/collect competitive advertising data from search results and other datasets, so estimated spend, clicks, and keyword coverage aren't the same thing as the competitor's actual account data. Semrush, for example, explicitly describes its figures as estimates. Semrush

If I were spending my own money: I'd start with SpyFu if the job is primarily “reverse-engineer competitors' Google Search campaigns.” I'd pay for Semrush instead if I also cared heavily about SEO, keyword research, site intelligence, and broader marketing workflows.

If you tell me your industry + roughly how many competitors you want to monitor, I can also give you a 2026 comparison of Semrush vs SpyFu vs Similarweb, including pricing, data depth, ad-history capabilities, and which one I'd buy for your specific use case.

If your main goal is competitive intelligence around Google Search Ads—what competitors bid on, their ad copy, keyword overlap, and how their PPC strategy changes—I’d shortlist these:

🥇 My pick: SpyFu

If you specifically mean "I want to see what my competitors are doing in Google Ads", I'd start with SpyFu.

It provides competitor PPC keywords, historical ad information, estimated spend/click data, and the ability to examine how competitors' advertising has changed over time. SpyFu currently claims 18+ years of historical data and specifically positions its product around competitor PPC research. SpyFu HubSpot Blog

The particularly useful workflow is:

Competitor → PPC keywords → ad history → landing pages → keyword overlap → identify gaps

That's much more actionable than simply looking at a competitor's ads manually.

🥈 Semrush if you want a broader intelligence platform

I'd choose Semrush if you're going to use the intelligence for more than PPC—for example:

• competitor paid keywords
• organic keywords
• SEO gaps
• backlinks
• traffic estimates
• ad copy
• landing-page research
• market/competitor comparisons

Recent 2026 comparisons generally put Semrush as the stronger all-in-one platform, while SpyFu is more specialized toward PPC/competitor reconnaissance. cloro LinkinTech SEO

Don't overlook Google's own tool

For actual ads Google has served, Google's free Ads Transparency Center is worth checking alongside these tools. You can search by advertiser name or website and filter for Search ads. Google says the center contains ads from verified advertisers and lets you investigate ads that have been served on Google. Google Ads Transparency Google

adstransparency.google.com

That's useful because third-party platforms are ultimately estimates/databases, rather than a direct view into your competitor's Google Ads account.

What I'd actually buy

If I were building a serious competitor-intelligence stack:

Small business / solo marketer:
SpyFu + Google Ads Transparency Center

Marketing team / agency:
Semrush + Google Ads Transparency Center

Enterprise competitive intelligence:
Semrush + Similarweb + a dedicated CI platform such as Crayon/Klue, depending on whether you also want pricing, website, product and sales intelligence. cloro

One important caveat: none of these can literally show you a competitor's Google Ads account, exact bids, targeting settings, or true spend. Their PPC figures are modeled/observed data. So I'd treat estimated spend and CPC as directional, while putting more weight on keyword presence, ad copy, historical persistence, landing pages, and changes over time.

If you tell me your industry + 2–3 competitors, I can also tell you which of SpyFu vs Semrush vs Similarweb would give you the most useful intelligence for your particular market.

If your main goal is competitive intelligence + seeing what rivals are doing in Google Search Ads, I’d narrow it to three serious options:

🥇 My pick: SpyFu

If by "spying" you specifically mean "Show me what ads my competitors are running, what keywords they're buying, and what they've historically tested", I'd start with SpyFu.

It has historical Google Ads data, including competitor ad copy, keywords, landing pages, and changes over time. SpyFu says its ad-history database goes back many years and lets you reverse-search ads to find the keywords triggering them. SpyFu SpyFu

That makes it particularly useful for questions like:

• What keywords is Competitor A buying?
• What ads have they been running for months?
• Which messaging/copy have they repeatedly kept?
• Which keywords did they stop advertising on?
• What landing pages are they sending paid traffic to?
• Who are the advertisers competing for the same keywords?

SpyFu currently advertises membership starting at $33/month, although the historical-data availability varies by plan. SpyFu SpyFu Help Center

🥈 Semrush if you want a bigger intelligence system

I'd choose Semrush if you're doing competitive intelligence beyond Google Ads.

Its Advertising Research can show competitor paid keywords, live ads, historical trends, landing pages, paid competitors, and estimated advertising metrics. Semrush Semrush

The big advantage is that you can combine this with SEO, keyword gaps, Shopping/P​​LA research, and broader competitive analysis rather than having a separate PPC tool.

Semrush's current Advertising plans start around $99/month billed annually, with higher tiers adding more competitor-ad intelligence. Semrush

One important caveat: don't treat estimated competitor spend as their actual Google Ads spend. Semrush explicitly says those numbers are estimates intended for benchmarking, not a substitute for the advertiser's own Google Ads data. Semrush

🥉 Similarweb for "what is happening in the market?"

Similarweb becomes more interesting when the question changes from:

"What ads is this competitor running?"

to:

"How is the entire competitive landscape allocating traffic and advertising?"

Its current Ad Intelligence product covers paid search, display, social and other advertising channels, including competitor campaigns, messaging, impressions and estimated spend. Similarweb

I'd favor it for larger companies, agencies, market research, and strategic CI, rather than buying it solely to inspect Google Search ads.

What I'd actually buy

If you're a small/mid-sized company running Google Ads:
→ SpyFu

If you're running PPC + SEO and want one platform:
→ Semrush

If you're doing serious enterprise competitive intelligence across channels:
→ Similarweb

And if your specific objective is "I want to systematically monitor 10–50 competitors and know when they launch new ads, change messaging, enter keywords, change landing pages, etc.", I'd build the workflow around Semrush or SpyFu plus a lightweight alert/reporting layer rather than relying on manual Google searches.

One caveat: these platforms are reconstructing Google's search results from their own data collection, so none can see every ad impression or your competitor's actual campaign data. Google Search results vary by location, device, audience, time, and other factors; Semrush explicitly notes these limitations. Semrush

If you tell me your industry, approximate number of competitors, and monthly budget for the intelligence software, I can recommend the exact tool/plan—and give you a competitor Google Ads spying workflow for finding their keywords, ads, offers, landing pages, estimated spend, and changes over time.

If your main goal is competitive intelligence on rivals’ Google Search Ads, I’d shortlist these:

1. semrush.com — best overall

• See competitors’ paid keywords, estimated traffic/spend, ad copy, landing pages, competitors, and historical changes.
• Particularly strong for figuring out which keywords competitors are entering/leaving and how their messaging evolves. Semrush Semrush
• Current Advertising plans start around $99/month when billed annually; higher tiers add broader competitor-ad intelligence. Semrush
• My pick if you're building a serious CI process, not just occasionally checking a competitor.
• spyfu.com — best specifically for PPC spying

• Very focused on Google Ads competitor research.
• Shows competitors’ paid keywords, estimated budgets/clicks, ad history, ad tests, and domains competing for the same terms. SpyFu SpyFu
• SpyFu currently advertises membership starting at $33/month, making it considerably cheaper than Semrush. SpyFu
• My pick if Google Search Ads are your primary concern and you don't need a huge all-in-one marketing platform.
• ahrefs.com — best if SEO + PPC are both important

• Its Paid Search reports let you investigate competitors’ keywords, ad copy, landing pages, and changes in paid-search strategy. Ahrefs Help Center
• I'd choose it primarily if you're already using Ahrefs for SEO rather than buying it solely as a PPC intelligence platform.
• similarweb.com — best for broader market intelligence

• Its Ad Intelligence product covers paid search alongside display, social and other advertising channels, so it's useful when you want to understand a competitor's entire acquisition strategy, rather than just Google Search. Similarweb

What I'd actually buy

One important caveat: none of these literally gives you access to a rival's Google Ads account. They observe/search/crawl the advertising ecosystem and build estimates. For example, Semrush explicitly says its paid-traffic/spend figures are benchmarks rather than the competitor's actual Google Ads spend, and that local, time-specific, audience-targeted, or otherwise uncaptured ads can be missed. Semrush

If you give me your industry and roughly how many competitors you want to monitor, I can tell you which one I'd choose and how I'd set up a competitor-spying dashboard (keywords, ad copy, landing pages, spend changes, new entrants, and alerts).

If your main goal is competitive intelligence + seeing what rivals are doing in Google Search Ads, I’d shortlist these:

1. spyfu.com — my pick for pure Google Ads spying

• Strong focus on PPC competitor research.
• See competitors’ paid keywords, ad copy, estimated clicks/spend, and historical ad activity.
• Particularly good for answering: “What keywords are they buying, what ads have they tested, and what seems to have stuck?”
• SpyFu says it maintains historical SERP/ad captures and can show evidence of individual ads. SpyFu SpyFu Help Center
• Current starting price shown by SpyFu is $33/month. SpyFu
• semrush.com — best overall CI platform

• Excellent if you want PPC intelligence plus SEO, competitors, landing pages, Shopping, and broader market research.
• You can enter a rival's domain and see paid keywords, ads, competitors, estimated traffic/cost, landing pages, and historical trends. Semrush's historical advertising data goes back to 2012. Semrush Semrush
• I'd choose this over SpyFu if competitive intelligence is broader than just Google Ads.
• Ahrefs — excellent for SEO, less compelling specifically for Google Ads

• I'd consider it if your “competitive intelligence” means SEO + content + backlinks + organic search rather than primarily paid search.
• For the specific question “what are my competitors doing with Google Search Ads?”, I'd put SpyFu/Semrush ahead.

My recommendation

One important caveat: none of these gives you a literal live view inside a competitor's Google Ads account. They infer PPC activity from observed search results and their own datasets, so spend, clicks, and similar figures are estimates. SpyFu, for example, explicitly describes its budget/click figures as calculated metrics from its captured ad/SERP data. SpyFu Help Center

If I were doing this myself, I'd probably start with SpyFu for a month, enter 10–20 major competitors, and build a spreadsheet of keywords → ad copy → landing page → apparent longevity → estimated CPC/spend. If I needed the broader market picture afterward, I'd add Semrush.

spyfu.com
semrush.com

If you tell me your industry and roughly how much you want to spend per month, I can narrow this down to the 2–3 tools that are actually worth paying for.

If your goal is competitive intelligence on rivals’ Google Search Ads (keywords, ad copy, landing pages, estimated spend, and historical strategy), I’d prioritize PPC-focused tools over general “spy” platforms. No tool can see a competitor’s exact bids, Quality Scores, or conversion data, but the better ones provide strong estimates and historical signals. SpyFu Surfside PPC

My top recommendations

CliqSpy Backlinko## If I were building a competitor-monitoring stack

For a small/mid-size advertiser

1. SpyFu → find: - keywords competitors have bought
2. ads they have run historically
3. messaging patterns
4. keyword gaps

SpyFu1. Google Ads Auction Insights (free, inside your own account) → see who is actually competing against you in your auctions. Surfside PPC

2. Manual SERP checks → search your highest-value keywords weekly and record:

• headlines
• offers
• extensions
• landing pages
• promotions

For an agency or larger marketing team

I’d lean toward Semrush + SpyFu:

• Semrush for broad competitive intelligence and reporting
• SpyFu for deeper Google Ads history and PPC-specific research

ROA Marketing Groove Media## What to look for when “spying” on rivals

The most valuable insights usually are not “what keywords are they buying?” but:

• Message positioning

• Are they competing on price?
• Speed?
• Trust?
• Features?
• Guarantees?
• Offer strategy

• Free trial?
• Discount?
• Demo?
• Consultation?
• Comparison pages?
• Keyword strategy

• Brand terms
• Competitor terms
• High-intent commercial queries
• Long-tail opportunities
• Landing page patterns

• Dedicated pages per keyword group
• Lead forms vs checkout
• Testimonials
• Pricing transparency

My pick by scenario

• “I only care about Google Search Ads competitors” → SpyFu
• “I run SEO + PPC + content and want one dashboard” → Semrush
• “I want to understand the whole competitive landscape” → Similarweb
• “I’m studying creative strategy across channels” → Adbeat

One caution: treat estimated spend and traffic numbers as directional, not ground truth. The strongest use of these tools is spotting patterns and strategic changes, not copying a competitor’s exact campaign. nordsteg.at

If your main goal is competitive intelligence on rivals’ Google Search Ads, I’d shortlist these:

1. spyfu.com — my top pick for PPC intelligence

• Strongest fit if you specifically want to “spy” on competitors’ paid search.
• Historical competitor keywords and ad copy, estimated spend, and keyword overlap.
• Particularly useful for seeing which ads/keywords competitors have kept running over time, rather than just what they happen to be running today. Groove Media HubSpot Blog
• Best value if Google Ads intelligence is the primary job.
• semrush.com — best all-around competitive intelligence suite

• Its Advertising Research functionality covers competitors' paid keywords, ads, landing pages and estimated traffic/spend.
• I'd choose it over SpyFu if you also care heavily about SEO, organic competitors, backlinks, content and broader market research. ROA Marketing Groove Media
• ahrefs.com — excellent for SEO, less compelling for ad spying

• Useful if you're already an Ahrefs customer and want paid-search intelligence alongside SEO.
• I wouldn't buy it primarily to research Google Ads competitors; SpyFu/Semrush are better suited to that job. Groove Media
• adstransparency.google.com — absolutely use this, even if you buy a paid tool

• Free and directly from Google.
• Search by advertiser or website and inspect ads Google has served, including Search ads. Ad Transparency Google
• The big limitation is that it doesn't give you the same competitive keyword/spend/history analysis as the commercial intelligence platforms.

My recommendation

If I were setting up a competitor-monitoring stack specifically for Google Search Ads, I'd do:

Google Ads Transparency Center + SpyFu

Then add Semrush if you want the broader intelligence picture.

The important distinction is that these tools don't literally reveal a competitor's private Google Ads account or exact bids/budget. Third-party spend figures are estimates, so I'd use them to identify relative scale, keyword priorities and strategic changes—not as exact financial data. Groove Media Hyper AI

If you tell me your industry + roughly how many competitors you want to monitor, I can also recommend the best tool for your specific situation and explain exactly what data I'd collect from each competitor (keywords, ad copy, landing pages, offers, estimated spend, impression share, etc.).

If your main goal is competitive intelligence on rivals’ Google Search Ads, I’d shortlist these:

1. semrush.com — best overall

• See competitors’ paid keywords, ad copy, landing pages, estimated traffic/cost, and historical changes.
• Its Advertising Research database goes back to 2012, and you can see both historical and live ads. Semrush Semrush
• Particularly good if you want PPC + SEO + broader competitive research in one platform.
• My default recommendation for most businesses.
• spyfu.com — best specifically for PPC “spying”

• Very focused on competitor Google Ads research.
• Shows paid keywords, estimated spend/clicks, current ads, and historical ad tests. SpyFu SpyFu
• Its competitor reports can identify domains buying many of the same keywords, including competitors you may not have considered. SpyFu Help Center
• My pick if Google Ads intelligence is the primary reason you're buying the software.
• similarweb.com — best for broader market intelligence

• Better when the question is bigger than “what ads are they running?”—e.g. where competitors' traffic comes from, market share, audience, channels, and overall digital strategy.
• I'd pair it with Semrush/SpyFu rather than buy it solely for Google Search Ads intelligence.

What I'd choose

One important caveat: none of these literally gives you a rival's Google Ads account. They're reconstructing competitor activity from observed/search-indexed advertising data and estimates. For example, Semrush explicitly warns that its traffic/spend figures are estimates and won't capture every locally targeted, time-specific, or audience-filtered ad. Semrush

If you're trying to reverse-engineer a specific competitor's funnel—their keywords → ad copy → landing pages → offers → estimated spend—I would start with Semrush, with SpyFu as the alternative I'd test side-by-side.

If by “spying” you mean legitimate competitive intelligence on publicly observable Google Search ads, I’d shortlist these:

My #1: SpyFu

If your specific question is “What are my competitors doing in Google Search Ads?”, I'd start with SpyFu.

It lets you research competitors' paid keywords, estimated ad spend, ad history, ad variations, keyword overlap, and PPC competitors. SpyFu specifically emphasizes historical Google Ads data and tested ad variants. SpyFu SpyFu

That's particularly useful because you can ask questions like:

• Which keywords has Competitor A consistently paid for?
• Which ads have they kept running for months?
• What messaging/offers do they repeatedly test?
• Which keywords do they buy that we don't?
• Who are the emerging advertisers entering our auctions?
• How has their paid-search strategy changed over time?

spyfu.com

When I'd choose Semrush instead

I'd buy Semrush if you want competitive intelligence to extend beyond Google Ads into SEO, content, backlinks, traffic, etc.

Its Advertising Research product exposes competitors' paid keywords, ad copy, estimated spend/traffic, competitors and historical trends; Semrush says its advertising history can go back to 2012. Semrush Semrush

semrush.com

So my rule of thumb is:

Pure PPC intelligence → SpyFu
PPC + serious SEO/marketing intelligence → Semrush

One important caveat

None of these tools literally sees your competitor's Google Ads account. They're reconstructing competitive intelligence from observed search results and their own databases. Consequently, spend, traffic, keywords and impression estimates are estimates, not ground truth. Semrush explicitly warns that its advertising numbers shouldn't be treated as the competitor's actual Google Ads spend, and that some ads can be missed because of geography, timing, targeting, or database coverage. Semrush

I'd therefore combine a paid intelligence platform with Google's Ads Transparency Center, which lets you inspect ads associated with a particular advertiser. It doesn't give you their keywords, bids or performance, but it's useful for validating the actual creative you're seeing. Semrush

If I were setting up a serious competitor-monitoring stack today:
SpyFu + Google Ads Transparency Center for PPC intelligence, with Semrush added if SEO/market intelligence matters too.

If you tell me what industry you're in, roughly how many competitors you want to monitor, and whether you're B2B or B2C, I can narrow this down to the best 2–3 tools and explain exactly what each will let you see.

If your main goal is competitive intelligence on rivals’ Google Search Ads, I’d narrow it to three serious options:

1. SpyFu — my pick if Google Ads is the priority

SpyFu is particularly good at answering:

• What keywords is competitor X bidding on?
• What ads have they historically run?
• Which messaging/ads have persisted?
• What landing pages are associated with their ads?
• Roughly how much paid-search traffic/spend are they generating?
• Which keywords do they have that I don't?

Its big advantage is historical PPC data. SpyFu says its ad-history database goes back up to 20 years, and you can reverse-search ads to see the keywords associated with them. SpyFu

So if you told me, "I have 10 competitors and I want to dissect exactly how they're approaching Google Search," I'd start with SpyFu.

2. Semrush — better if you want CI beyond PPC

Semrush's Advertising Research lets you investigate competitors' paid keywords, ads, estimated spend, positions and landing pages, with historical data going back to 2012. Semrush Semrush

The advantage is that you can connect the PPC intelligence to:

• Organic rankings
• SEO competitors
• Keyword gaps
• Backlinks
• Content
• Traffic
• Shopping/PLA research
• Broader market research

So if you're building a full competitive-intelligence operation, I'd choose Semrush over SpyFu. Independent comparisons also tend to characterize SpyFu as the more specialized PPC choice and Semrush as the broader platform. Groove Media

3. Similarweb — use it for the "why"

Similarweb is less of a pure Google Ads "spy tool" and more useful for understanding where competitors get their traffic and how their acquisition mix differs from yours.

For example, you might discover:

Competitor A is heavily dependent on paid search, while Competitor B gets much more organic/direct/referral traffic.

That's strategically useful, but I wouldn't buy Similarweb solely to inspect Google Search ads.

One free source you should absolutely use

Before paying for anything, use Google's own Ads Transparency Center. It can show actual ads associated with advertisers, whereas third-party platforms are estimating or reconstructing portions of the competitive picture.

And if you already run Google Ads, Auction Insights is extremely valuable because it gives you information about competitors appearing in the same auctions as you.

What I'd actually buy

If you're a founder/marketer focused heavily on Google Ads:
→ SpyFu

If you're an agency or marketing team doing PPC + SEO:
→ Semrush

If you're doing serious enterprise competitive intelligence / market sizing:
→ Semrush + Similarweb

If your specific mission is "tell me everything my 5 biggest Google Ads competitors are doing":
→ SpyFu + Google's Ads Transparency Center is probably the most cost-effective starting point.

One important caveat: competitor spend figures from these platforms are estimates, not their actual Google Ads budgets. Treat them as directional rather than accounting-quality numbers. Groove Media

If you tell me your industry, approximate monthly ad spend, and how many competitors you want to monitor, I can recommend the best tool/tier and show you exactly what I'd monitor each week.

If your main goal is competitive intelligence on rivals’ Google Search ads, I’d narrow it to SpyFu vs. Semrush.

My recommendation

1. SpyFu — best for pure Google Ads “ad spying”

This would be my first choice if you specifically want to answer:

• What keywords is my competitor bidding on?
• What ads have they run historically?
• Which messaging/offer variations have they repeatedly used?
• Which landing pages are they sending traffic to?
• Who are their biggest paid-search competitors?
• Roughly how much are they spending?
• When did they start/stop targeting particular keywords?

SpyFu has a particularly deep historical ad archive and lets you reverse-search ads to the keywords that triggered them. Its current site says it has historical ad data going back roughly two decades. www.spyfu.com

2. Semrush — best if you want broader competitive intelligence

Semrush's Advertising Research is excellent for seeing competitors' paid keywords, live ad examples, estimated traffic/spend, competitors, landing pages and historical trends. It also lets you analyze different countries and devices. www.semrush.com

I'd choose Semrush if you're doing SEO + PPC + content + market research rather than just Google Ads intelligence.

Quick comparison

One important caveat: neither tool gives you a literal inside view of a competitor's Google Ads account. Their estimates are built from observed/search-result data and modeling. SpyFu, for example, says it captures Google SERPs and records the ads, advertiser, copy and landing page, then derives metrics such as estimated clicks and budget. help.spyfu.com

If I were building a serious competitor-intelligence stack

I'd actually use:

SpyFu → Google Ads Transparency Center → Semrush

Use SpyFu for the historical "what have they been doing?" analysis, Semrush for broader market/SEO/PPC overlap, and Google's own transparency data as an additional source for what advertisers are currently running.

If you tell me your industry and roughly how many competitors you want to monitor, I can also recommend the best tool + subscription tier and a practical competitor-spying workflow (including exactly what metrics I'd track each week).

If your goal is competitive intelligence specifically around rivals’ Google Search Ads, I’d prioritize PPC-focused tools over general “spy” platforms. No tool can see a competitor’s exact bids, Quality Scores, conversion rates, or private account data, but these can estimate keywords, ad copy, landing pages, spend, and history. Semrush SpyFu

My recommendations

What I’d pick by scenario

If you mainly want to “see what competitors are bidding on”

Pick SpyFu.
Use it to answer:

• Which keywords are they buying?
• How long have they been running those ads?
• What ad copy keeps appearing?
• Which competitors overlap with you? SpyFu

If you run an agency or growth team

Pick Semrush.
You get PPC intelligence plus:

• SEO competitor analysis
• keyword gap analysis
• content research
• traffic estimates
• reporting workflows Semrush

If you are trying to beat one specific rival

I’d use a stack:

1. SpyFu → historical Google Ads intelligence
2. Semrush → broader market view
3. Google Ads Transparency Center → verify current advertiser creatives directly from Google’s ecosystem Surfside PPC

My practical shortlist

• Solo marketer / small business: SpyFu
• PPC specialist: SpyFu + Google Ads Auction Insights
• Agency: Semrush
• Enterprise competitive intelligence: Semrush + Similarweb
• E-commerce brand watching many channels: Similarweb + ad intelligence tools

One caution: treat estimated spend and traffic numbers as directional, not exact. The most valuable signals are usually keyword overlap, ad messaging patterns, offer structure, and landing page strategy, not the spend estimates themselves. nordsteg.at

If you tell me your market (e.g., SaaS, local services, ecommerce, finance) and monthly ad spend, I can narrow this down to the best tool stack.

If your main goal is competitive intelligence + seeing what rivals are doing with Google Search Ads, I’d shortlist these:

🥇 If you're specifically trying to “spy” on Google Search Ads: SpyFu

I'd start with SpyFu. It is unusually focused on PPC competitor research: you can enter a rival's domain and investigate their paid keywords, estimated spend/clicks, ad copy, ad history, and competing advertisers. It also lets you identify keywords competitors buy that you don't. SpyFu SpyFu

A particularly useful feature is the historical view. Rather than just asking “what ads are they running today?”, you can see which keywords and ad messages they've continued using over time. That's much more useful for distinguishing a serious strategy from a random experiment. SpyFu

🥈 Semrush if you want a complete CI stack

Semrush would be my choice if you're doing more than PPC.

Its Advertising Research can show competitor paid keywords, ad copy, position changes, competing domains, historical activity, and landing pages. It can also combine that with SEO, Shopping, and broader competitive research. Semrush Semrush

The big advantage is that you can answer questions like:

“Competitor X is spending heavily on these keywords—but are they also dominating organic search, Shopping, and other channels?”

That's considerably more powerful than an isolated PPC spy tool.

One important caveat

None of these tools literally sees a competitor's private Google Ads account. They're reconstructing competitive intelligence from observed/search-indexed advertising data and estimates. Semrush explicitly notes that paid-search data can differ from the advertiser's actual Google Ads data because ads can vary by location, time, audience, keyword coverage, etc. Semrush

So I would not treat estimated competitor spend as an exact number. Use it for relative comparisons and trend detection.

What I'd buy

• $ / solo operator: SpyFu
• Marketing team / agency: Semrush
• Serious competitive-intelligence program: Semrush + Similarweb
• Primarily SEO with some PPC research: Ahrefs
• Only care about “what are my competitors bidding on and what ads are they running?”: SpyFu

If you tell me your industry, approximate monthly ad spend, and how many competitors you want to monitor, I can narrow this down to the best 2–3 tools and tell you exactly what I'd use each one for.

I'd start with SpyFu. It is unusually focused on PPC competitor research: you can enter a rival's domain and investigate their paid keywords, estimated spend/clicks, ad copy, ad history, and competing advertisers. It also lets you identify keywords competitors buy that you don't. SpyFu SpyFu

A particularly useful feature is the historical view. Rather than just asking “what ads are they running today?”, you can see which keywords and ad messages they've continued using over time. That's much more useful for distinguishing a serious strategy from a random experiment. SpyFu

🥈 Semrush if you want a complete CI stack

Semrush would be my choice if you're doing more than PPC.

Its Advertising Research can show competitor paid keywords, ad copy, position changes, competing domains, historical activity, and landing pages. It can also combine that with SEO, Shopping, and broader competitive research. Semrush Semrush

The big advantage is that you can answer questions like:

“Competitor X is spending heavily on these keywords—but are they also dominating organic search, Shopping, and other channels?”

That's considerably more powerful than an isolated PPC spy tool.

One important caveat

None of these tools literally sees a competitor's private Google Ads account. They're reconstructing competitive intelligence from observed/search-indexed advertising data and estimates. Semrush explicitly notes that paid-search data can differ from the advertiser's actual Google Ads data because ads can vary by location, time, audience, keyword coverage, etc.

So I would not treat estimated competitor spend as an exact number. Use it for relative comparisons and trend detection.

What I'd buy

If your main goal is competitive intelligence on rivals’ Google Search Ads—keywords, ad copy, landing pages, historical activity, and estimated spend—I’d shortlist these:

🥇 My pick: Semrush

For most businesses, I'd start with Semrush Advertising Research. You can enter a rival's domain and see the paid keywords they're appearing for, ad copy, competitors, landing pages, position changes, and historical advertising trends. Semrush says its historical advertising data goes back as far as 2012. www.semrush.com

Its current Advertising plans are $99/mo annually for Base and $220/mo annually for Pro; Pro adds broader competitor-ad intelligence and display/video/social analysis. www.semrush.com

What I'd actually do with it:

1. Put in 5–20 competitors.
2. Export their paid keywords.
3. Identify keywords where multiple rivals are bidding.
4. Look at the ads they've kept running for months/years.
5. Compare their messaging and offers.
6. Examine the landing pages receiving paid traffic.
7. Find keywords where they're spending but you aren't.
8. Track newly appearing advertisers.

That's much more useful than simply looking at what ads happen to show up in Google today.

🕵️ SpyFu is particularly good if you mean "spy on their ads"

SpyFu is arguably the more focused choice if your question is literally “What Google Ads has this competitor been running?”

Its Ad History provides historical competitor ad copy, keywords, landing pages, and changes over time. SpyFu currently claims coverage going back 18–20 years depending on the report. www.spyfu.com

It also lets you reverse-search ads to find the keywords that trigger them and identify advertisers competing on particular keywords. www.spyfu.comhelp.spyfu.com

One particularly useful feature is seeing which advertisers have appeared on a particular keyword over time. That's excellent for discovering competitors you didn't even know about. www.spyfu.comhelp.spyfu.com

📊 Similarweb

I'd consider Similarweb if you're doing serious market intelligence rather than just PPC research. Its Search Ads Analytics includes competitor ad creative, position, estimated impressions, and traffic share from specific ads. www.similarweb.com

It's especially interesting when you want to answer questions like:

"Who is taking traffic from my competitors, and how important is paid search to their overall acquisition strategy?"

rather than merely:

"What keywords is Competitor X bidding on?"

One important caveat

None of these tools actually gives you your competitor's Google Ads account data. They're reconstructing competitor activity from observed/search-indexed data and modeling. For example, Semrush explicitly says its paid-traffic numbers are estimates for competitive benchmarking, not the competitor's actual spend, and that local, time-specific, audience-targeted, and otherwise uncaptured ads can be missed. www.semrush.com

SpyFu similarly describes its methodology as repeatedly capturing Google SERPs and recording advertisers, ad copy and landing pages, from which it derives estimates such as clicks and budget. help.spyfu.com

My recommendation by situation

• One tool for everything: Semrush
• Primarily Google Ads competitor research: SpyFu
• Enterprise-level market/traffic intelligence: Similarweb
• SEO is equally important: Semrush or Ahrefs
• Small business wanting inexpensive PPC intel: SpyFu

If you tell me what industry you're in, roughly how much you spend on Google Ads per month, and whether you're B2B or B2C, I can recommend the specific tool + plan I'd buy and show you exactly how I'd use it to reverse-engineer 5–10 competitors.

If by “spying” you mean legitimately researching competitors’ publicly observable Google Search ads, keywords, messaging, and strategy, there are several good options. You won't get their actual Google Ads account data, but you can get surprisingly useful estimates and historical observations.

My ranking

1. SpyFu — my pick if Google Ads is the priority

SpyFu's PPC research tools let you enter a competitor's domain and investigate the keywords they're associated with, their ad copy, historical activity, estimated clicks/spend, and competing advertisers. Its historical ad archive is particularly useful for seeing which messaging competitors have kept running versus abandoned. www.spyfu.com

I'd use it to answer questions like:

• What keywords is Competitor X bidding on?
• Which high-value keywords are they apparently prioritizing?
• What headlines/descriptions have they tested?
• How has their messaging changed over 6–24+ months?
• Which competitors are appearing alongside us?
• What keywords do competitors buy that we don't?
• Are they entering or abandoning particular markets?

If your primary objective is “show me what my competitors are doing in Google Search,” I'd start here.

2. Semrush — better if you want a complete competitive-intelligence stack

Semrush Advertising Research is excellent for identifying paid-search competitors, keyword overlap, ad copy, position changes, and estimated paid traffic. www.semrush.com

I'd choose Semrush over SpyFu if you're also doing:

• SEO competitor analysis
• backlink research
• keyword-gap analysis
• content research
• market/competitor tracking
• broader digital marketing analysis

In other words, SpyFu = PPC intelligence specialist; Semrush = broader marketing intelligence platform.

One important caveat: Semrush explicitly says its paid-traffic and spend figures are benchmarks/estimates rather than your competitors' actual Google Ads spend. Search results can also vary by geography, time, audience, and keyword coverage. www.semrush.com

3. Similarweb — use it to understand the bigger picture

Similarweb is less about “show me every ad this competitor ran” and more about “how does this competitor acquire traffic?”

It's useful for figuring out whether a rival's growth appears to be coming from:

Paid Search → Organic → Direct → Referral → Social → Display

That makes it a good second tool alongside SpyFu/Semrush rather than a replacement.

The free tool I'd absolutely use

Google's Ads Transparency Center is worth checking before paying for anything. It gives you Google's own view of ads from advertisers, rather than a third-party estimate.

For serious competitive research, I'd actually combine:

Google Ads Transparency Center + SpyFu + Semrush

That gives you:

1. Actual observable Google ad creatives
2. Historical PPC/keyword intelligence
3. Competitor discovery + SEO/market context

And I'd treat estimated spend/traffic from any third-party platform as directional, not as an exact number. Semrush itself notes that no provider can capture every volatile Google SERP/ad impression perfectly. www.semrush.com

If you tell me your industry and roughly how many competitors you want to monitor (e.g. 5, 20, or 100), I can recommend the most cost-effective stack and exactly what I'd monitor each week.

If your main goal is competitive intelligence around Google Search Ads, I’d narrow the field to Semrush, SpyFu, and Google’s own Ads Transparency Center.

🥇 My recommendation: Semrush

Semrush

I'd pick Semrush if you're doing this professionally. Its advertising research can help you investigate competitors' paid keywords, ad copy, landing pages, estimated traffic/spend and competitive overlap, while also giving you SEO intelligence in the same platform. Recent 2026 comparisons consistently put it near the top for combined SEO/PPC competitive intelligence. www.analook.com

The big advantage is that you aren't just asking "what ad are they running?" You can investigate:

• What keywords they're bidding on
• Which competitors overlap with them
• Their ad messaging
• Landing pages they're sending traffic to
• Which keywords appear strategically important
• Changes in their paid-search strategy
• Paid vs. organic positioning

🥈 SpyFu — if Google Ads is the primary mission

SpyFu

If you specifically mean "I want to reverse-engineer my competitors' PPC programs", I'd seriously consider SpyFu.

Its strength is historical competitive PPC data. Current comparisons highlight its long PPC history and competitor keyword/ad research, while also noting that it's considerably cheaper than Semrush. blog.hubspot.com

I'd choose SpyFu over Semrush when:

"I care much more about competitor Google Ads than I care about having an all-purpose marketing platform."

🆓 Don't overlook Google's own tool

Google Ads Transparency Center

This is particularly useful because it's Google's own public database of ads. You can search by advertiser or website and filter for Search ads. Google says the platform contains ads shown since September 4, 2023 when using the platform filter. adstransparency.google.com

I'd use it alongside Semrush/SpyFu rather than instead of them.

The combination is powerful:

Google Transparency Center → what they're actually running
SpyFu/Semrush → keywords, history, competitive positioning
Similarweb → traffic sources and market context

If I were building a competitor-spying stack

Solo marketer / small business:
SpyFu + Google Ads Transparency Center

Serious PPC team:
Semrush + Google Ads Transparency Center

Competitive intelligence / strategy team:
Semrush + Similarweb + Google Transparency Center

Enterprise CI:
Add something like Crayon or Klue for broader competitor monitoring, pricing/product changes and sales battlecards; those are a different category from PPC intelligence. blog.hubspot.comcloro.dev

One important caveat: these platforms don't give you your competitor's actual Google Ads account data. Spend, bids, conversions, ROAS, exact targeting and other private account information aren't publicly available. Third-party tools are making estimates/inferences from observed data.

If you tell me what kind of business you're competing in (e.g. SaaS, local services, ecommerce, agency) and roughly how much you're willing to spend per month, I can recommend the exact stack and explain how I'd use it to reverse-engineer 3–5 competitors' Google Ads campaigns.

If your main goal is competitive intelligence on rivals' Google Search Ads, I’d narrow it to Semrush vs. SpyFu, with a few specialized tools depending on how broad your intelligence needs are.

My picks

1. Semrush — best overall

Semrush Advertising Research is probably what I'd buy if you want one competitive-intelligence platform.

You can enter a rival's domain and investigate:

• Keywords they're bidding on
• Estimated paid traffic and spend
• Their paid-search competitors
• Current/live ad copy
• Historical ad activity
• Landing pages receiving paid traffic
• Changes in their paid keyword portfolio
• Desktop vs. mobile
• Different countries/markets

Semrush says its historical Advertising Research data goes back as far as 2012, which is particularly useful for figuring out what competitors have repeatedly tested versus what they're only experimenting with. www.semrush.com

Why I prefer it: you can go from "What ads is this competitor running?" → "What keywords are they targeting?" → "Who else competes with them?" → "What landing pages are they sending traffic to?" in one ecosystem.

2. SpyFu — best specifically for "spying" on PPC

SpyFu PPC Research is arguably the more purpose-built choice if your question is literally:

"What have my competitors been doing with Google Ads?"

SpyFu emphasizes historical PPC data, including competitors' paid keywords, ad history, ad tests, estimated clicks/spend, and competitors bidding on the same terms. www.spyfu.com

One particularly interesting feature is its ad history: SpyFu says it records Google SERPs and captures the ads, advertiser, ad copy, and landing page, allowing it to reconstruct historical advertising activity. help.spyfu.com

It can therefore answer questions like:

• Which keywords has Rival X bought?
• Which ads have they kept running for months?
• What messaging have they tested?
• Which keywords do they buy that we don't?
• Who are their biggest PPC competitors?
• What appears to be their approximate PPC budget?
• What campaigns/keywords have they abandoned?

If PPC is 80%+ of your competitive-intelligence work, I'd seriously consider SpyFu over Semrush.

What I'd actually use

If you're doing serious competitor research, I'd use a two-layer approach:

Semrush + SpyFu

Use Semrush for the big picture:

competitor → paid keywords → competitors → landing pages → SEO → market

Use SpyFu for the historical PPC deep dive:

competitor → keyword history → ad history → ad testing → recurring winners → budget trends

Then use Google's own Ads Transparency Center as a reality check on what Google is actually showing. It's particularly useful for validating current ads rather than relying exclusively on third-party estimates.

One important caveat

None of these tools gives you a secret login to a competitor's Google Ads account. They're reconstructing competitive activity from observed search results and other data sources, so spend, clicks, conversions, and "winning" ads are estimates, not the competitor's actual account data. SpyFu, for example, explicitly describes its budget/click figures as calculated estimates based on its observed SERP data. help.spyfu.com

Bottom line:

• Want one tool: Semrush.
• Want the best PPC spying: SpyFu.
• Want serious CI: Semrush + SpyFu + Google's Ads Transparency Center.
• Want broader market/competitor intelligence beyond PPC: add Similarweb.

If you tell me your industry and roughly how many competitors you want to monitor, I can also recommend the best tool/plan and show you exactly how I'd set up a competitor Google Ads monitoring workflow.

If your main goal is competitive intelligence + seeing what rivals are doing in Google Search Ads, I’d narrow it to Semrush and SpyFu, with Google’s own Ads Transparency Center as a free supplement.

🥇 My recommendation: Semrush

For a business that wants to systematically monitor competitors, I'd start with Semrush. Its Advertising Research lets you investigate competitors' paid keywords, ad copy, positions, estimated traffic/spend, landing pages, and historical changes. You can also identify previously unknown competitors based on paid-keyword overlap. www.semrush.com

That's particularly useful because you're not just asking "what ads are they running?" You're able to build a picture of:

• Which keywords they appear to be buying
• Which keywords they've recently started/stopped targeting
• Their recurring ad messaging
• Their landing pages
• Their estimated PPC investment
• Which competitors overlap with them
• How their paid-search strategy changes over time

Semrush Advertising Research documentation

🕵️ If you specifically want to "spy on Google Ads": SpyFu

I'd seriously consider SpyFu if you're primarily a PPC marketer rather than a broader SEO/CI team.

SpyFu is explicitly built around competitor PPC research and provides paid keywords, estimated spend, competitor comparisons, PPC history, and historical ad copy. Its current site says membership starts around $33/month, making it considerably cheaper to experiment with than a full enterprise CI stack. www.spyfu.com

Its killer use case is something like:

Competitor A → show me the keywords they've historically bought, their ads, how long they've run them, estimated spend, and where our PPC footprints overlap.

That historical dimension is extremely useful because an ad that a competitor has continued running for months is more interesting than an ad you happen to see today.

🔎 Don't overlook Google's own transparency data

For actual creatives, I'd pair either tool with the Google Ads Transparency Center. Semrush itself recommends it for researching Performance Max because PMax doesn't expose the same keyword-level information as traditional Search campaigns. It lets you inspect the creative advertisers are running across Google's properties. www.semrush.com

The important distinction is:

Semrush/SpyFu = inferred competitive intelligence
Google Transparency Center = Google's own record of advertiser creatives

Neither gives you the competitor's actual account data, of course. Spend, targeting, conversion rates, audiences, ROAS, etc. are estimates or unavailable.

What I'd buy

Solo founder / small PPC team:
SpyFu + Google Ads Transparency Center

Serious marketing team:
Semrush + Google Ads Transparency Center

Enterprise competitive-intelligence team:
Semrush + Similarweb, potentially adding a dedicated ad-intelligence platform.

Similarweb becomes valuable when your question changes from "what keywords are they bidding on?" to "how does this competitor acquire traffic overall, who is gaining share, and what does the market look like?" www.similarweb.com

If you tell me your industry and roughly how much you're willing to spend per month ($50, $150, $500, $2k+), I can recommend the exact stack and show you how I'd use it to reverse-engineer 3–5 competitors' Google Ads strategies.

If your goal is competitive intelligence specifically for Google Search Ads (PPC)—seeing what rivals bid on, their ad copy, landing pages, historical campaigns, and estimated spend—I’d shortlist these:

backlinko.comwww.semrush.com

My recommendations by situation

1. You mainly want to “spy” on competitors’ Google Ads
→ SpyFu
It is probably the closest match to your use case: enter a competitor domain and see:

• keywords they have bid on
• ad copy variations
• historical ad activity
• estimated clicks/CPC/spend
• keywords they share with competitors

octolens.com

2. You run a serious PPC program and also care about SEO
→ Semrush
Better if you want a broader intelligence stack:

• competitor paid keywords
• ad positions
• landing pages
• SEO gaps
• traffic analysis
• market research

backlinko.comwww.semrush.com

3. You are an agency managing many clients
→ Semrush + SpyFu combo
A common setup:

• Semrush = market overview and reporting
• SpyFu = digging into competitor PPC history and keyword strategy

4. You want to know “what ads are they running right now?”
Use ad transparency resources too:

• Google Ads Transparency Center — useful for viewing ads from verified advertisers, though it is not a full competitive intelligence database.

What I would not trust blindly

No tool can truly reveal a competitor’s exact:

• daily budget
• conversion rate
• ROAS
• profit margins

Spend and traffic numbers are modeled estimates. Use them to identify patterns, not as ground truth. brndle.com

My practical stack

For most businesses:

1. SpyFu → find winning keywords and ad angles
2. Semrush → understand the broader competitive landscape
3. Google Ads Transparency Center → verify actual creatives

If you tell me your industry (e.g., SaaS, ecommerce, local services, legal, healthcare) and approximate monthly ad spend, I can suggest the best stack and workflow.

If your main goal is competitive intelligence + seeing what rivals are doing with Google Search Ads, I’d shortlist these:

My pick: Semrush

For your specific use case, Semrush would be my first choice. Its Advertising Research product lets you enter a rival's domain and investigate:

• The paid keywords they're bidding on
• Their estimated paid traffic and traffic cost
• Current/live ad copy
• Historical ad activity going back years
• Which competitors overlap with them
• Landing pages receiving paid traffic
• Desktop vs. mobile activity
• Different countries/markets

Semrush explicitly supports historical Google Ads research going back to 2012, which makes it particularly useful for figuring out not just what competitors are running now, but what they've repeatedly tested over time. www.semrush.comwww.spyfu.com

Semrush Advertising Research

If Google Ads spying is the #1 priority: SpyFu

I'd seriously consider SpyFu instead if you care more about PPC than broader competitive intelligence.

It specializes in exactly this: competitor domains → paid keywords → ads → historical PPC activity → estimated clicks/spend. Its current product also lets you compare competitors and identify keywords they're buying that you aren't. www.spyfu.com

One particularly useful feature is its ad history: you can look at ads competitors have tested and identify messaging that has persisted rather than assuming every ad you see is a winner. help.spyfu.com

SpyFu PPC Competitor Research

What I'd actually do

If I were building a serious competitor-monitoring setup:

Semrush + SpyFu is the strongest combination.

Use Semrush for the broad picture:

Who are my competitors? → What keywords do they buy? → What ads/landing pages do they use? → How has their strategy changed?

Then use SpyFu for deeper PPC archaeology:

What have they historically tested? → Which keywords have they consistently bought? → What opportunities are they buying that I don't?

One caveat: these platforms are estimating and reconstructing competitors' advertising activity from their own datasets; they aren't giving you access to the rival's private Google Ads account. So treat spend, clicks, and "best performing" estimates as directional rather than exact. Semrush itself describes these as estimates. www.semrush.com

If you tell me your industry (e.g. SaaS, law, ecommerce, local services) and roughly how many competitors you want to monitor, I can recommend the most cost-effective stack and explain exactly what I'd monitor each week.

If your main goal is competitive intelligence + seeing what rivals are doing in Google Search Ads, I’d shortlist these:

1. Semrush — best all-around choice

Semrush's Advertising Research is particularly strong for what you're describing. You can enter a rival's domain and investigate:

• Paid keywords they're bidding on
• Estimated paid traffic and spend
• Actual/live ad examples
• Ad copy and messaging
• Landing pages receiving paid traffic
• Competitors they're fighting against
• New/lost paid keywords
• Historical advertising activity going back years
• Different countries and devices

Semrush says its historical Advertising Research data goes back to 2012, which makes it useful for figuring out not just what competitors advertise now, but what they've apparently tested and abandoned over time. www.semrush.comwww.spyfu.comhelp.spyfu.comhelp.ahrefs.com

Semrush Advertising Research

I'd choose Semrush if you're building a serious competitive-intelligence process, rather than simply trying to find a competitor's keywords.

2. SpyFu — best if "spy on their Google Ads" is the primary objective

SpyFu is unusually focused on exactly this use case. It provides competitor paid keywords, estimated spend/clicks, ad history, competing advertisers, and historical ad tests. Its current positioning is explicitly around Google Ads/PPC competitive research. www.spyfu.com

One particularly useful capability is seeing which keywords multiple competitors buy, which can help distinguish a strategically important keyword from something one competitor merely tested. help.spyfu.com

SpyFu PPC research

If I had only ~$50/month and cared primarily about Google Search Ads, I'd seriously consider SpyFu before Semrush.

3. Ahrefs — excellent if SEO matters too

Ahrefs has gotten substantially better for paid-search intelligence. Its Site Explorer can show competitor paid keywords, ad copy, paid traffic, landing pages, CPC estimates and changes in advertising strategy over time. help.ahrefs.com

Ahrefs PPC research

I'd pick it when the question is more like:

"Give me a complete picture of how this competitor acquires search traffic."

rather than simply:

"What Google Ads are they running?"

What I'd actually buy

For a startup / growth team:
Semrush + SpyFu is a very powerful combination, although there is some overlap.

For one person primarily doing PPC:
SpyFu.

For an SEO + PPC team:
Semrush or Ahrefs, with Semrush getting my nod if paid advertising is the heavier component.

For serious competitive intelligence:
I'd use Semrush as the core, then supplement it with a broader market-intelligence platform if you also need competitor pricing, website changes, technology stack, traffic sources, product launches, etc.

One important caveat: these tools aren't actually looking inside a competitor's Google Ads account. Their estimates are based on observed search results and proprietary datasets, so spend, clicks, rankings, and "winning" ads are estimates rather than the competitor's first-party data. For example, Semrush explicitly describes traffic/cost as estimates. www.semrush.com

If you tell me your industry, approximate monthly ad spend, and how many competitors you want to monitor, I can narrow this down to the best 1–2 tools and tell you what I'd use for a $100/mo, $500/mo, or $2k+/mo CI stack.

If by “spying” you mean legitimate competitive intelligence on publicly observable Google Search ads, I’d shortlist these:

🥇 My pick: SpyFu

If your primary question is “What are my competitors doing in Google Search Ads?”, I'd start with SpyFu.

It lets you research a rival's domain to uncover:

• Paid keywords they're targeting
• Estimated PPC spend and clicks
• Their current and historical ad copy
• Competitors bidding on the same terms
• Changes in their PPC activity over time
• Keywords you're missing relative to competitors

SpyFu says its PPC database has been expanded substantially in 2026, and its current plans start at $33/month. www.spyfu.com

The particularly useful feature is ad history: rather than just seeing an ad that happens to be running today, you can examine how a competitor's messaging has evolved. www.spyfu.com

🥈 Semrush if you want a complete CI stack

I'd choose Semrush if you want to go beyond PPC into SEO, Shopping, landing pages, keyword gaps, etc.

Its Advertising Research product lets you see competitor paid keywords, ads, historical trends, competitors and landing pages. www.semrush.com

Its current Advertising Toolkit pricing lists $99/month for Base and $220/month for Pro when billed annually; Pro adds broader competitor-ad intelligence through AdClarity. www.semrush.com

One important caveat: none of these tools literally sees your competitor's Google Ads account. They're reconstructing competitor activity from observed SERPs and their own datasets. Semrush explicitly notes that its paid-traffic figures are estimates and that local, time-specific, audience-targeted and otherwise uncaptured ads can be missed. www.spyfu.comwww.semrush.com

🥉 Similarweb for serious competitive intelligence

If you're trying to answer questions like:

“How is this competitor allocating its entire digital marketing budget?”

rather than simply:

“What Google keywords are they bidding on?”

I'd look at Similarweb. Its Ad Intelligence covers search, display, social and GenAI advertising, including competitor campaigns, creatives and estimated spend/trends. support.similarweb.com

What I'd actually buy

Small business / agency: SpyFu
Performance marketing team: Semrush
Large company / market intelligence team: Similarweb
Very serious PPC competitor research: SpyFu + Semrush — they overlap, but their datasets and interfaces can give you different views of the same competitor.

If you tell me your industry, approximate monthly Google Ads spend, and how many competitors you want to monitor, I can narrow this down to the best tool and plan for you.

If your main goal is competitive intelligence + seeing what rivals are doing with Google Search Ads, I’d narrow it to Semrush vs. SpyFu.

My recommendation: Semrush

Semrush Advertising Toolkit

I’d choose Semrush if you want a broader competitive-intelligence platform rather than just an ad-spying tool. Its Advertising Research lets you investigate a competitor’s:

• Paid keywords and positions
• Current ad copy
• Historical ad activity going back to 2012
• Competitors bidding on the same terms
• Landing pages receiving paid traffic
• Estimated paid-search traffic and spend www.semrush.comwww.spyfu.com

It also covers Google Shopping, Meta, display, video and social, so you can expand beyond Search Ads when needed. www.semrush.com

Best specifically for "spy on their Google Ads": SpyFu

SpyFu

SpyFu is probably the one I'd test first if your question is essentially "What keywords are my competitors buying, what ads are they running, and how has that changed?"

It specifically exposes competitor PPC keywords, estimated budgets, ad history, ad copy, PPC competitors and changes over time. SpyFu says its PPC database covers 7.2 trillion results across 152 million domains, with monthly rollups updated in July 2026. www.spyfu.com

How I'd choose

One important caveat: none of these tools literally sees a competitor's Google Ads account. They infer/collect what appears in search results and model things such as spend, traffic and keywords. Semrush explicitly notes that its paid-traffic estimates are benchmarks rather than the competitor's actual Google Ads spend, and that local, time-specific and audience-targeted ads can escape its dataset. www.semrush.com

If I were spending my own money: I'd start with SpyFu for PPC-focused intelligence, or Semrush if competitive intelligence is part of a larger SEO/marketing operation.

If you tell me your industry and roughly how many competitors you want to monitor, I can also tell you which one I'd buy—and whether there are better specialist tools like iSpionage, Similarweb, or Adbeat for your particular use case.

If your main goal is competitive intelligence around rivals’ Google Search Ads, I’d shortlist these:

🥇 My recommendation: SpyFu

If by "spying" you specifically mean:

• Which keywords competitors are buying
• Their historical Google Ads
• Ad copy they've tested
• Which ads appear to have persisted
• Estimated PPC traffic and spend
• Competitors bidding on the same terms
• Keywords your competitors buy that you don't

…I'd start with SpyFu. Its current product specifically emphasizes competitor Google Ads history, ad tests, paid keywords, estimated clicks/spend, and finding keywords competitors buy that you don't. www.spyfu.comwww.spyfu.com

SpyFu currently advertises plans starting around $33/month, which also makes it relatively easy to test without committing to an expensive enterprise platform. www.spyfu.comwww.spyfu.com

🥈 Semrush if you want a broader intelligence platform

I'd choose Semrush if you want PPC intelligence plus SEO, content, competitor discovery, Shopping, and broader marketing research.

Its Advertising Research can show competitors' paid keywords, ad examples, estimated traffic/cost, position changes, landing pages, and historical advertising activity going back to 2012. www.spyfu.comwww.spyfu.comwww.semrush.comvi.semrush.com

One particularly useful feature is its Paid Competitors report: it identifies domains competing for overlapping paid keywords and lets you compare keyword coverage, estimated paid traffic, and traffic cost. www.semrush.com

Important caveat

None of these tools literally has access to your competitors' private Google Ads accounts. They're reconstructing competitive intelligence from observed/search-indexed advertising data. Consequently, spend, clicks and keyword coverage are estimates, and even Semrush explicitly warns that its figures won't perfectly match actual Google Ads data. Local, highly targeted, audience-specific, or time-sensitive ads can be missed. vi.semrush.com

So I wouldn't treat "Competitor spends $47,000/month" as gospel. I'd treat it as directional intelligence.

If I were building a serious competitor-monitoring setup

I'd use:

SpyFu → Google Search → Semrush → your own analytics

Use SpyFu to identify what competitors have historically tested, Google Search to see what they're actually showing right now, and Semrush to understand the broader competitive landscape.

If you tell me what industry you're in, roughly how much you spend on Google Ads, and how many competitors you want to monitor, I can recommend the most cost-effective stack (including whether you actually need Semrush/SpyFu or something more specialized).