ChatGPT answers, unedited

Yes. If by “predicted conversion probability at the keyword level” you mean software that estimates how likely a click/search is to convert and then uses that prediction to adjust bids, there are a few options worth looking at.

Best fits for a freelance PPC manager

The important distinction

If you specifically want:

Keyword → predicted CVR → economically optimal CPC bid

that's somewhat different from Google's Smart Bidding.

Google's system is actually more granular: it predicts conversion likelihood for individual auctions/impressions, incorporating signals such as device, location, time and context, rather than simply assigning one static predicted CVR to each keyword. services.google.com

For a freelancer, I'd therefore look at BiddingLab first if you want a third-party system that explicitly exposes conversion-probability-driven bidding. Its documentation says the system lowers CPC for unprofitable keywords and only enters auctions when predicted conversion probability meets its cost-benefit criteria. www.biddinglab.comservices.google.com

Scaletrics is interesting if you want something more like a complete PPC optimization layer: it analyzes individual search terms, identifies high-conversion queries, promotes them to keyword candidates, and has smart bid management tied to CPA/value targets. www.scaletrics.com

If you're asking because you want to build or offer this as a service to PPC clients, I can also compare the available tools specifically on API access, Google Ads integration, keyword-level CVR prediction, bid-control granularity, pricing, and suitability for a solo freelancer.

If you mean software that predicts conversion probability and then uses that prediction to decide what to bid, the strongest options are:

1. Google Ads Smart Bidding — my first choice

Google's own system predicts the likelihood that a particular click will convert and uses that prediction, together with contextual signals, to set a bid at auction time. It isn't really a simple "conversion probability per keyword" model: Google says it learns at the search-query level and incorporates signals such as device, location, time, browser, OS, and the actual query. support.google.comsupport.google.com

So if your goal is:

"Bid more when the probability of conversion is high, bid less when it's low."

Smart Bidding already does this—and at a much finer level than keyword-level bidding.

Google Ads Smart Bidding

2. Optmyzr — probably the best third-party option for PPC freelancers

Optmyzr has explicit keyword-level bid strategies. For example, its Bid to Target CPA (Keywords) strategy uses historical conversion data and progressively expands the lookback window from 7 to 90 days until enough conversion data exists. help.optmyzr.com

Its Conversion Grabber is particularly relevant: it identifies converting keywords that are losing impression share because of ad rank and recommends bid increases for keywords expected to generate incremental conversions. help.optmyzr.com

Optmyzr

3. If you specifically want your own conversion-probability model

This is where I'd consider building a lightweight system around the Google Ads API.

For example:

keyword/query → predicted P(conversion) → expected CPA/value → recommended CPC

You could train the model using each client's historical clicks/conversions, then output recommended keyword bids. This gives you something Google/Optmyzr don't: a transparent probability score you can show clients, such as:

• Keyword A — 8.4% predicted CVR → increase bid 18%
• Keyword B — 2.1% predicted CVR → decrease bid 12%
• Keyword C — 0.4% predicted CVR → pause/reduce exposure

The important distinction is that Google's Smart Bidding is generally better at the actual auction-level prediction, whereas a freelancer-built keyword model can be better for explainability, reporting, and cross-client workflow. Google explicitly says Smart Bidding operates at auction time rather than simply maintaining one bid per keyword. support.google.comsupport.google.com

My recommendation for a PPC freelancer: start with Google Smart Bidding + Optmyzr rather than building ML yourself. If what you're really looking for is a tool that gives you a predicted conversion probability for every keyword and automatically converts that into CPC recommendations, that's a narrower requirement—and I can identify the 5–10 tools that specifically do that.

If you mean Google Ads PPC freelancing (managing client search campaigns), the software category you’re looking for is usually called AI bid management / predictive bidding / Smart Bidding optimization. These tools estimate conversion probability (often using keyword, query, audience, device, time, and historical conversion signals) and adjust bids toward a CPA or ROAS goal. Google

Good options for PPC freelancers:

For a solo PPC freelancer, I’d usually shortlist:

1. Google Ads Smart Bidding + strong conversion tracking

• Best starting point because it already uses auction-time prediction. Google
• Use strategies like Target CPA or Target ROAS once enough conversion data exists.
• Optmyzr

• Better if you manage many client accounts and need automation, scripts, alerts, and reporting.
• Adalysis

• Better if you want deeper PPC analysis rather than a pure autopilot bidder. Adalysis
• Adlogic

• Worth testing if you specifically want a tool claiming per-keyword predictive bid adjustments rather than Google’s auction-time approach. Adlogic

A note: modern Google Ads automation often does not optimize only at the keyword level anymore; it can optimize at the search query + auction level, using context signals such as device, location, time, and user intent. Google So a tool that says “keyword-level conversion probability” may be narrower than Google’s own system.

If you’re a freelancer managing 5–50 client accounts, I’d compare tools differently than if you’re managing ecommerce accounts, lead-gen, or local service PPC.

If you mean Google/Bing PPC software that predicts conversion probability and uses that prediction to determine bids, there are a few different categories.

Best fit for a PPC freelancer

1. Google Ads Smart Bidding — probably the strongest option

• Uses machine learning to predict conversion likelihood at auction time, rather than simply assigning one static bid to each keyword.
• Considers the actual search query plus device, location, time, browser, OS, ad characteristics, and other signals.
• Supports Target CPA, Target ROAS, and Maximize Conversions/Conversion Value.
• This is especially attractive for freelancers because you can manage multiple client accounts without buying another bid-management platform. support.google.combusiness.google.com
• Importantly, Google's current system is actually more granular than keyword-level bidding: it learns from search-query and auction-level data, so a single keyword can receive different bids depending on the auction context. support.google.combusiness.google.com

Google Ads Smart Bidding documentation

2. AdsOptimizer Lab — interesting if you're managing many clients
This is a third-party agency-oriented platform. Its keyword/search-term engine says it scores queries by intent and conversion probability, while its automation handles bid management, budget allocation, negatives, etc. adsoptimizerlab.com

AdsOptimizer Lab

I'd investigate this one if your goal is specifically "I freelance and need one optimization layer across lots of client accounts."

3. Build your own Bayesian bid model — if you want true keyword-level control
There is actually academic work directly matching what you're describing: Bayesian models can estimate keyword performance under uncertainty and then use online/bandit optimization to select bids. link.springer.com

The basic concept is:

Predicted CVR × conversion value × target efficiency → optimal CPC

The hard part is estimating CVR reliably when a keyword has only a handful of clicks/conversions. Bayesian smoothing/hierarchical models are useful here because they can "borrow" information from related keywords instead of overreacting to tiny samples.

One important distinction

If what you're looking for is software that literally produces a predicted CVR for every keyword and then automatically calculates a CPC bid from that CVR, that's different from Google Smart Bidding.

Google's system doesn't really work as:

keyword → predicted CVR → keyword bid

It works more like:

auction/query + dozens of contextual signals → predicted conversion probability → auction-time bid

Google explicitly says its models learn at the query level rather than simply the keyword level. support.google.combusiness.google.com

So if you're a freelancer looking for a transparent, keyword-level bid optimizer where you can see something like:

then Google Smart Bidding isn't quite that product. A third-party optimizer or your own model is closer to what you're describing.

If you tell me whether you're managing Google Ads, Microsoft Ads, or both, and roughly how many client accounts, I can narrow this down to the 3–5 tools that are actually worth considering for a freelancer.

Yes. If by that you mean software that estimates a keyword/search term’s probability of converting and uses that estimate to change bids, there are a few categories worth looking at.

Best fits for a freelance PPC manager

The important distinction is that Google's system is actually more sophisticated than simple keyword-level CVR bidding. Smart Bidding predicts conversion likelihood at the individual auction/search-query level, incorporating things such as device, location, time, audience, actual query and ad characteristics. support.google.com

If you're specifically looking for the workflow:

keyword → predicted CVR → target CPA/value → calculated CPC bid → automatically update bids

then AdsOptimizer Lab is unusually close to what you're describing. It says its keyword/search-term engine scores queries by conversion probability and its optimization system handles bid management. adsoptimizerlab.com

But there's a big caveat

If you're a freelancer managing client accounts, I wouldn't necessarily replace Google Smart Bidding with a keyword-level third-party bidder.

Google explains that its Smart Bidding models can borrow information across keywords/ad groups and, importantly, learn from search-query-level performance across the account. That helps with low-volume keywords where a raw keyword CVR would be statistically unreliable. support.google.com

For example:

• Keyword A: 10 clicks, 1 conversion → observed CVR = 10%
• Keyword B: 100 clicks, 5 conversions → observed CVR = 5%

A naïve system might bid twice as aggressively on A. That's dangerous because 1 conversion isn't enough evidence to conclude A is actually twice as good.

A better system uses predicted CVR / Bayesian or ML estimates, incorporating the broader account's data and contextual signals.

If you're building this as a freelancer

I'd shortlist:

1. Google Smart Bidding — best if you want the platform itself doing auction-level prediction.

2. Optmyzr — best if you want a freelancer/agency control layer around Google Ads, including automation and bid-management workflows.

3. AdsOptimizer Lab — worth investigating if you specifically want an external system that talks in terms of predicted conversion probability and automated optimization.

4. A custom Google Ads API system — potentially the most interesting if you're managing enough accounts to justify it. You can calculate your own smoothed/predicted CVR and generate bid recommendations, while letting Google handle auction-time signals.

One thing I'd be careful about: "keyword-level predicted CVR" is not necessarily the optimal architecture anymore. Google's own documentation explicitly says query-level modeling can outperform treating the keyword as the unit of prediction, particularly with broad/phrase match. support.google.com

If you're asking because you're looking for a tool you can use across 10–50 freelance client accounts, I can compare Optmyzr vs Adalysis vs PPC Protect vs AdsOptimizer Lab vs building your own, including pricing, API access, MCC support, and whether each one actually changes bids automatically.

Yes. If by “predicted conversion probability at the keyword level” you mean software that uses historical conversion behavior to estimate which keywords are more likely to convert, then adjusts bids accordingly, there are a few good options.

1. Google Ads Smart Bidding — probably the best answer

Google Ads Smart Bidding

Google's system predicts conversion rate/value for each auction, using search-query performance plus signals such as device, location, time, browser, OS, language, and combinations of those signals. It then uses those predictions to determine the bid. support.google.comsupport.google.comsupport.marinsoftware.com

One important distinction: it's not really “keyword-level bidding” anymore. Google explicitly says Smart Bidding learns at the search-query level across the account, rather than simply assigning a conversion rate to each keyword. That's actually more granular than keyword-level modeling. support.google.comsupport.google.comsupport.marinsoftware.com

For a freelancer managing client accounts, I'd generally use Target CPA / Target ROAS / Maximize Conversions / Maximize Conversion Value rather than trying to reproduce Google's model yourself. support.google.com

2. Optmyzr — best if you want freelancer-level control

Optmyzr

Optmyzr sits on top of Google Ads and provides additional automation and optimization. Its Conversion Grabber, for example, identifies converting keywords that are losing impression share because of ad rank and recommends selective bid increases. help.optmyzr.com

It also has automated bidding tools, Rule Engine workflows, and value-based bidding tools. help.optmyzr.com

I'd pick Optmyzr if you're a PPC freelancer who wants:

• multiple client accounts
• automated rules
• bid recommendations
• keyword-level visibility
• the ability to override/augment Google's automation
• less spreadsheet/API work

3. Marin Software — particularly interesting for your specific description

Marin Software

Marin's algorithmic bidding explicitly calculates bids for keywords, ad groups, product groups, and placements. Its system uses recent conversion rate and statistical thresholds, and it uses Bayesian blending to deal with low-volume keywords. support.marinsoftware.com

That makes Marin conceptually closer to what you described than Google's system if you're specifically thinking:

keyword → estimated conversion probability → optimal CPC bid

What I'd recommend for a freelancer

If you're asking because you're looking for software to manage PPC clients, I'd rank them:

Google Smart Bidding → Optmyzr → Marin

But if you're asking because you want to build/offer a proprietary bidding system, that's a different answer. A useful architecture would be:

keyword/search query → predicted P(conversion) → expected conversion value → allowable CPC → bid

with Bayesian smoothing/hierarchical modeling for low-volume keywords.

If that's what you're investigating, I can also compare the actual algorithms/features of 5–10 PPC bid-management platforms and identify which ones genuinely do predictive conversion modeling versus merely applying rules to historical CPA.

If you mean software that predicts conversion probability and uses that prediction to decide what CPC bid a keyword/auction deserves, there are a few good options—but there’s an important distinction:

Best options for a PPC freelancer

The biggest surprise is that Google Ads itself is probably closest to your requirement. Smart Bidding doesn't simply look at historical keyword conversion rate. Google says its models learn primarily at the search-query/auction level and incorporate device, location, time, audience, browser, OS, ad creative and other signals to predict conversion likelihood. support.google.comservices.google.com

So if your idea is:

Keyword → predicted CVR → calculate economically optimal CPC → automatically change bids

Google's native system is already doing a more sophisticated version:

Auction/query + contextual signals → predicted conversion probability/value → optimal auction-time bid

Google explicitly describes its system as using predicted conversion rate, conversion value, budget and market information to determine the CPC bid for an auction. services.google.com

If you specifically want keyword-level predicted CVR

That's a slightly different use case.

Google's Keyword Planner can provide forecasted conversion rate and conversions for keywords, but those are planning forecasts rather than a persistent, freelancer-controlled bidding model. business.google.com

For a freelancer managing many client accounts, I'd look at Optmyzr first if you want a tool sitting on top of Google Ads, and Google Smart Bidding first if you're comfortable letting Google's model do the actual bidding.

If what you're actually looking for is a tool where you upload historical keyword data, it predicts CVR for every keyword—including low-volume keywords—and then recommends a specific CPC bid for each one, that's a narrower category. I can find the 3–5 products that most closely match that exact workflow and compare their pricing/API/automation capabilities.

Yes. If by “using predicted conversion probability at the keyword level” you mean a tool that estimates how likely each keyword/search opportunity is to convert and then uses that estimate to determine the economically appropriate bid, there are a few good options—but there’s an important distinction.

Best options for a PPC freelancer

Optmyzr is probably the closest off-the-shelf fit. Its tools can identify converting keywords that are constrained by rank and recommend bid increases, while its Rule Engine lets you build your own formulas and automated bidding logic. help.optmyzr.com

Adalysis is another strong freelancer-oriented option. Its keyword bid suggestions incorporate factors such as Quality Score, lost impression share, Google position estimates, search volume, historical performance, and your stated goal (including target CPA/ROAS). adalysis.com

But there's a key technical caveat

If you specifically want:

Predicted P(conversion | keyword) → calculate expected conversion value → determine optimal CPC bid

then Google Ads Smart Bidding is actually more sophisticated than most third-party keyword-bid tools, but it doesn't work the way you're describing.

Google says Smart Bidding predicts conversion likelihood at the auction/query level, incorporating contextual signals such as device, location, time, browser, OS, etc. It deliberately uses query-level information across the account rather than relying solely on each keyword's historical conversion rate. support.google.com

So, conceptually:

Traditional freelancer workflow

keyword history → CPA/ROAS → bid adjustment

Smart Bidding

auction/query + context + historical data → predicted conversion likelihood → auction-time bid

Custom ML workflow

keyword/query + context + first-party data → your predicted P(conv) → economic value → bid

That last approach is what I'd investigate if you're looking for a freelancer-focused bidding product that explicitly exposes predicted conversion probability rather than hiding the model inside an automated bid strategy.

If you tell me whether you mean Google Search manual CPC, Microsoft Ads, or a custom tool/API, I can narrow this down to the 3–5 products that actually do probability-based bidding rather than merely providing bid recommendations.

If you mean software that predicts conversion probability and uses that prediction to determine PPC bids, the strongest option today is actually Google Ads Smart Bidding.

• Google Ads Smart Bidding — uses ML to predict conversion likelihood for each auction, incorporating search-query performance plus contextual signals such as device, location, time, browser, etc. It then adjusts the bid at auction time. Importantly, it isn't really a keyword-level bidding model anymore; Google says it learns at the search-query level across the account, which is generally more granular than keyword-level data. support.google.comsupport.google.com

Google Ads Smart Bidding

For a freelancer managing multiple client accounts, I'd distinguish between:

If you specifically want keyword-level predicted CVR

That's a slightly different product than Smart Bidding. You could build a model like:

Predicted CVR(keyword, query, device, geo, etc.) → expected conversions/click → economically optimal CPC

and use it to recommend or push bids through the Google Ads API.

This can be attractive for freelancers because you can incorporate client-specific economics—lead quality, close rate, revenue per customer, margins, etc.—rather than optimizing merely for Google's reported conversion.

Google itself recommends giving Smart Bidding enough conversion data because its models can borrow information across queries/accounts when individual keywords don't have enough data. support.google.com

If you're looking for a specific SaaS product that already does the predicted-CVR → keyword-bid workflow, rather than building it yourself, I can research the current PPC bid-management market and identify the closest 5–10 tools for freelancers.

For PPC freelancers looking for software that optimizes bids using predicted conversion probability (ideally at keyword/search-term level), the best options depend on whether you manage Google Ads, Microsoft Ads, Amazon PPC, or multiple clients.

1. Google Ads Smart Bidding — best native option

Google Ads

• Uses machine learning to predict the likelihood of a conversion and adjusts bids automatically at auction time. support.google.com
• Uses signals beyond the keyword itself: search query, device, location, time, browser, audience, and other contextual factors. support.google.com
• Strategies:
  • Target CPA
  • Target ROAS
  • Maximize Conversions
  • Maximize Conversion Value

Best for: freelancers managing accounts with enough conversion volume (often 30–50+ conversions/month per campaign is a practical starting point).

2. Optmyzr — best freelancer/agency workflow tool

Optmyzr

Good for freelancers who need:

• automated bid rules
• PPC audits
• optimization recommendations
• client reporting
• scaling across many accounts

It is less of a pure “predict conversion probability per keyword” engine and more of a PPC automation layer that works alongside Google’s bidding algorithms.

Best for: freelancers with 5–50 client accounts who want efficiency and control.

3. Skai — enterprise-grade predictive bidding

Skai

Features:

• AI-driven bid optimization
• cross-channel management
• predictive models
• budget allocation

Best for: agencies managing large spend accounts.

4. Marin Software — advanced portfolio bidding

Marin Software

Useful for:

• large keyword portfolios
• automated bidding rules
• multi-channel paid search management

Best for: larger PPC operations.

5. BiddingLab — keyword-focused automated bidding

BiddingLab

Claims:

• AI-supported real-time bid management
• keyword management
• conversion prediction features
• automated CPC adjustments based on profitability signals www.biddinglab.com

Best for: search-focused freelancers who want a dedicated bidding tool.

6. Adalysis — optimization assistant

Adalysis

Strong for:

• bid adjustment analysis
• keyword insights
• testing
• alerts

It is more analytics/recommendation driven than a fully autonomous predictive bidder. adalysis.com

A practical freelancer stack

A key point: modern Google Ads does not really optimize only at the keyword level anymore. Its strongest models predict conversion probability at the auction/search-query level and adjust bids dynamically rather than simply assigning one bid per keyword. support.google.com

If you mean a tool that a solo PPC freelancer can white-label or use to manage client accounts automatically, the shortlist changes (Optmyzr, Shape.io, TrueClicks, etc.).

If you mean software that estimates a keyword’s likelihood of converting and then uses that probability to inform the CPC bid, there are a few different categories. For a PPC freelancer, I’d look at these:

1. Optmyzr — best fit for freelancers/agencies

This is probably the closest match to what you're describing. Optmyzr lets you automate keyword-level bid optimization, including rules that set bids toward a target CPA or ROAS using historical conversion data. Its current tooling also includes Conversion Grabber, which identifies converting keywords losing impression share and recommends selective bid increases. help.optmyzr.com

The important distinction: Optmyzr doesn't appear to market this as simply “predicted conversion probability × CPC.” Rather, it combines historical performance, CPA/ROAS targets, impression-share opportunity, and Google Smart Bidding/automation. www.optmyzr.com

2. Google Ads Smart Bidding — strongest actual ML option

If your clients have enough conversion data, Google's native Smart Bidding is hard to beat. It predicts conversion likelihood at the auction level and adjusts bids based on signals such as device, location, time, audience, query/context, etc.

The catch for a freelancer is that you don't get a simple, transparent “keyword X has a 7.3% predicted conversion probability, therefore bid $Y” interface. Google handles the prediction and auction-time bid internally.

3. Optmyzr + your own probability model — best if you specifically want keyword-level probabilities

If your goal is actually:

Predicted P(conversion | keyword) → expected conversion value → economically optimal CPC

then I'd seriously consider building a lightweight model yourself and using Optmyzr/Google Ads API to execute the resulting bid changes.

For example:

Expected value per click = P(conversion | keyword) × value per conversion

Then your maximum economically justified CPC can be derived from your target margin/CPA/ROAS.

This is particularly attractive for freelancers because you can pool historical data across client accounts only where appropriate and permitted, while still calibrating the model separately for each account.

My ranking for a PPC freelancer

If you're specifically looking for a commercial product that exposes a predicted conversion probability for each keyword and then automatically calculates the bid from it, that's a narrower requirement. I wouldn't assume Optmyzr does exactly that—their documented keyword bidding uses historical conversion data/target CPA or ROAS rather than exposing a raw probability score. help.optmyzr.com

If you tell me whether you're optimizing Google Search, Microsoft Ads, or both, I can identify the tools that most closely match “predicted keyword conversion probability → optimal CPC” and compare their pricing/API capabilities.

If you mean software that predicts the probability that a click will convert and uses that prediction to determine bids, the strongest options are:

1. Google Ads Smart Bidding — best overall
   • Uses machine learning to predict conversion probability at auction time, using query-level historical data plus signals such as device, location, time, browser, language, and time of day. support.google.comhelp.optmyzr.com
   • Supports Target CPA, Target ROAS, Maximize Conversions, and Maximize Conversion Value.
   • You can use portfolio bid strategies across multiple campaigns, which is particularly useful for freelancers managing several client campaigns. support.google.com
   • Important distinction: it isn't really "one predicted CVR per keyword." Google explicitly models at the query/auction level, which is more granular than keyword-level bidding. support.google.com

2. Optmyzr — best for freelancer/operator control
   • Useful as a management and optimization layer on top of Google Ads.
   • It can analyze performance and make data-driven bid recommendations, including ML-based recommendations and custom rules. help.optmyzr.com
   • However, if you're specifically looking for a tool that independently predicts conversion probability for every keyword and calculates an optimal CPC, Optmyzr isn't as direct a match as Google's own Smart Bidding.

If your requirement is specifically:

keyword → predicted conversion probability → expected value → recommended CPC/bid

then I'd look at Google Ads API + your own model rather than relying on a third-party PPC platform.

For example, you could estimate:

Expected conversion value per click = P(conversion | keyword/context) × conversion value

and then derive a bid from your target CPA/ROAS, while incorporating CPC, competition, impression share, and uncertainty.

That's especially interesting for a freelancer managing many smaller accounts, because Google's Smart Bidding can suffer when an individual campaign has sparse conversion data; Google itself says its query-level modeling helps address that data scarcity. support.google.com

If you tell me whether you want (a) an off-the-shelf SaaS, (b) software you can use across multiple client accounts, or (c) a tool/API where you can actually see the predicted conversion probability, I can narrow this down to the best 3–5 options.

If you mean software that estimates the probability/value of a conversion for each keyword and then uses that prediction to determine bids, there are a few categories worth separating.

Best options for a PPC freelancer

Optmyzr is probably the closest fit for a freelancer who wants control. It can make keyword-level bid recommendations, including Target CPA/ROAS strategies, expensive-keyword bid reductions, and its Conversion Grabber identifies converting keywords that are losing impression share and recommends bid increases. help.optmyzr.com

The important distinction, though, is that Optmyzr isn't simply taking a model's predicted P(conversion | keyword) and calculating the optimal CPC from it. If that's specifically what you're looking for, I'd look at Google Smart Bidding or Adspert rather than ordinary PPC rule engines.

If you're building your own bidding system

The model you're describing is roughly:

Expected conversion value = predicted conversion probability × conversion value

and then choosing the CPC bid based on expected value, auction economics, target CPA/ROAS, and the marginal probability of conversion.

For example, if your model predicts:

• Keyword A: 8% conversion probability
• Keyword B: 2%
• Keyword C: 0.4%

you'd want the system to bid substantially more aggressively on A provided the additional CPC still produces an acceptable expected CPA/ROAS.

For a freelancer managing relatively small accounts, I'd generally choose Google Smart Bidding first, and use Optmyzr on top of it when you need cross-account monitoring, rules, reporting, keyword-level interventions, and more control. Optmyzr specifically supports layering optimization tools around Smart Bidding rather than requiring you to replace it. www.optmyzr.com

If you tell me whether you're looking for (a) a tool to use for your clients or (b) software/API to build your own keyword-level predictive bidding model, I can narrow this down to the 3–5 best choices and compare pricing, API access, and how their bidding actually works.

If by “predicted conversion probability at the keyword level” you mean software that models how likely a click/search is to convert and then uses that prediction to adjust PPC bids, there are a few categories worth looking at.

The important distinction: Google Ads itself is now very strong here. Smart Bidding predicts conversion likelihood at the auction/query level, rather than simply assigning one conversion probability to each keyword, and uses contextual signals such as device, location, time, browser, query, etc. support.google.comsupport.google.com

Best options for a PPC freelancer

1. Google Ads Smart Bidding — best default

• Target CPA
• Target ROAS
• Maximize conversions
• Maximize conversion value
• Uses ML predictions and auction-time signals.
• Particularly useful when you have enough conversion data.
• Can operate across multiple campaigns via portfolio strategies. support.google.com

For most freelance accounts, I'd start here rather than adding another bidding platform.

2. Google Ads + your own prediction layer — best if you specifically want keyword-level modeling

If you want something more like:

Keyword → predicted CVR → expected CPA/value → recommended CPC

you can build a lightweight system using Google Ads data exported into Python/BigQuery/Sheets, train a model on historical clicks/conversions, and then use the predictions to recommend or automate bid changes.

This is particularly interesting for freelancers managing many smaller accounts where Google's automated bidding may not have much account-specific data.

3. Third-party PPC bid-management platforms

These can make sense when you're managing many accounts and need centralized automation, rules, reporting, and cross-platform bidding. However, I'd distinguish them from a true keyword-level predicted-CVR model: many modern platforms ultimately leverage the underlying ad platforms' auction-time bidding rather than independently predicting every keyword's conversion probability.

One important correction

If you're specifically looking for “keyword-level predicted conversion probability,” Google actually argues that query-level modeling is better than keyword-level modeling. A single keyword can match many different search queries, each with different conversion likelihoods. Google's Smart Bidding therefore learns from query-level data and uses it across the account. support.google.comsupport.google.com

So for a freelancer, I'd think about the stack like this:

If you're asking because you want a tool specifically for freelancers that takes historical keyword data and outputs a predicted CVR + optimal bid for each keyword, that's a narrower category—and I can identify the actual software products that do that rather than just general Google Smart Bidding.