ChatGPT answers, unedited

The best choice depends on whether you mainly need lead capture, advanced popup targeting, or a full email automation platform. These are the strongest options:

My picks by scenario

If you already have an email platform:

• Klaviyo user → use Klaviyo Forms first; add OptinMonster/Privy if you need more advanced onsite targeting.
• Mailchimp user → Mailchimp forms may be enough; upgrade to OptinMonster if conversions matter.
• ActiveCampaign user → use a popup tool that passes tags/custom fields into ActiveCampaign.

If you sell products online:

1. Klaviyo + its forms (best overall ecommerce stack)
2. Privy (Shopify-focused)
3. OptiMonk (personalized ecommerce popups) getpopupforge.com

If you run a service business or B2B site:

1. OptinMonster
2. HubSpot forms/popups
3. ConvertKit or Mailchimp for simpler newsletters

If you want the easiest setup:

• Mailchimp or Omnisend
• If you want maximum conversion optimization: OptinMonster
• If you want the best long-term automation engine: Klaviyo

Features I would prioritize:

• Native integration with your email provider
• Tags/custom fields passed from forms
• Double opt-in support
• Exit-intent and mobile targeting
• A/B testing
• Analytics tied to signup source
• Ability to trigger automations immediately after signup

If you tell me your email platform (Klaviyo, Mailchimp, ActiveCampaign, HubSpot, ConvertKit, etc.), website platform (WordPress, Shopify, Webflow, Squarespace, custom), and whether this is for ecommerce or lead generation, I can narrow it to the best 2–3 choices.

If your goal is popup + embedded signup forms that feed directly into your email lists and trigger automations, I’d narrow it to these:

My top picks

1. Klaviyo — best if you're selling products

Klaviyo can create popup, flyout, full-page, and embedded forms directly inside the platform, with targeting and list/segment integration. That means a signup can immediately enter the appropriate welcome flow or other automation. Klaviyo Help Center Klaviyo Help Center

klaviyo.com

I'd choose it if you have Shopify/e-commerce, need sophisticated segmentation, or expect to build increasingly complex customer journeys.

2. Kit — best if you're a creator/newsletter business

kit.com

Kit is particularly clean if your workflow is essentially:

Form → tag/segment → welcome sequence → lead magnet → ongoing newsletter/sales automation.

Its forms support popup, inline and slide-in formats, and forms can directly trigger Visual Automations. Kit Kit Help

3. Mailchimp — best if you want something straightforward

mailchimp.com

Mailchimp supports both embedded and popup forms and has a large ecosystem of integrations. Mailchimp Mailchimp

I'd pick it if you don't need especially sophisticated segmentation/automation.

One important distinction

If you already have an email platform and are looking specifically for a better popup/form builder, I'd look at a dedicated tool such as OptinMonster, Wisepops, or Typeform rather than replacing your email system. Klaviyo itself lists Typeform and Wisepops among form tools that can sync data into Klaviyo. Klaviyo

So my recommendation depends heavily on your existing stack:

• Shopify/e-commerce → Klaviyo
• Newsletter/creator/course business → Kit
• Already using Mailchimp → probably stay with Mailchimp initially
• B2B + CRM → HubSpot
• Already happy with your email provider but hate its forms → OptinMonster/Wisepops

If you tell me what email platform you're currently using (and what website platform—WordPress, Shopify, Squarespace, Webflow, etc.), I can give you the 2–3 best choices for your exact setup, including pricing and which has the best popup targeting/automation.

1. Klaviyo — best if you're selling products

Klaviyo can create popup, flyout, full-page, and embedded forms directly inside the platform, with targeting and list/segment integration. That means a signup can immediately enter the appropriate welcome flow or other automation. Klaviyo Help Center Klaviyo Help Center

klaviyo.com

I'd choose it if you have Shopify/e-commerce, need sophisticated segmentation, or expect to build increasingly complex customer journeys.

2. Kit — best if you're a creator/newsletter business

kit.com

Kit is particularly clean if your workflow is essentially:

Form → tag/segment → welcome sequence → lead magnet → ongoing newsletter/sales automation.

Its forms support popup, inline and slide-in formats, and forms can directly trigger Visual Automations. kit.com help.kit.com

3. Mailchimp — best if you want something straightforward

mailchimp.com

Mailchimp supports both embedded and popup forms and has a large ecosystem of integrations. mailchimp.com mailchimp.com

I'd pick it if you don't need especially sophisticated segmentation/automation.

One important distinction

If your goal is popup + embedded signup forms that feed directly into email lists and trigger automations, I’d narrow the field to these:

1. OptinMonster — best dedicated popup/form software

optinmonster.com

This would be my #1 if you're keeping your existing email platform and want a better front-end signup system.

It has sophisticated targeting/display rules, including things like exit intent, scroll behavior, page targeting, device, referral source, and visitor behavior. It also has native integrations with a large number of email/CRM platforms. OptinMonster OptinMonster

The particularly useful part is that it can also embed a form from an email provider that doesn't have a native integration, using HTML/JavaScript. OptinMonster OptinMonster

Choose it if:
You already use something like Mailchimp, Kit, ActiveCampaign, HubSpot, etc., and want really good conversion-oriented popups without replacing your email system.

2. Kit — best all-in-one for creators

kit.com

If you haven't committed to an email provider yet, Kit is probably the cleanest overall setup.

Its forms support:

• Inline embedded forms
• Modal/popups
• Slide-ins
• Sticky bars
• Tags and segmentation
• Visual automations
• Email sequences
• Landing pages

Kit's current form builder explicitly supports modal, slide-in, sticky-bar, and inline forms, and provides JavaScript/HTML embeds. Kit Help Center Kit Help Center

And because the forms, subscriber database, tagging, sequences, and visual automations live in the same platform, there's less integration plumbing to maintain. Kit

Choose it if:
Your business is primarily content, newsletters, courses, coaching, digital products, or a personal brand.

3. Klaviyo — best for ecommerce

If you're selling physical products, I'd strongly consider Klaviyo rather than adding a separate popup platform.

The advantage is that signup behavior can become part of your broader customer automation system—welcome sequences, abandoned-cart flows, post-purchase flows, segmentation, etc.

Choose it if:
You're running Shopify or another ecommerce operation and email/SMS revenue is a major channel.

4. HubSpot — best for lead generation + CRM

HubSpot makes more sense when a signup isn't simply "join my newsletter," but rather:

Someone downloads something → becomes a lead → gets segmented → enters an automated sequence → potentially gets contacted by sales.

In that scenario, the CRM becomes more important than having the world's fanciest popup.

Choose it if:
You're doing B2B, consulting, agencies, professional services, or anything with a sales pipeline.

5. Mailchimp — easiest mainstream option

Mailchimp can certainly handle embedded forms, signup forms, lists/segments, and automations. And OptinMonster has a direct Mailchimp integration if you want better popups while retaining Mailchimp as the email backend. OptinMonster

I'd choose it primarily if simplicity and familiarity matter more than advanced conversion optimization.

My recommendation

I'd make the decision based on your existing stack:

Already have an email platform you like?
→ OptinMonster

Starting from scratch and primarily building an audience/newsletter?
→ Kit

Selling products online?
→ Klaviyo

Generating B2B/service leads?
→ HubSpot

Already deeply invested in Mailchimp?
→ Mailchimp + OptinMonster if you need much better popup targeting.

The biggest distinction is that OptinMonster is primarily the acquisition layer, whereas Kit/Klaviyo/HubSpot can be the form + list + segmentation + automation + email layer. That makes OptinMonster particularly attractive if you don't want to migrate your existing email database.

If you tell me which email platform you're currently using (e.g. Mailchimp, Kit, ActiveCampaign, Klaviyo, HubSpot, Constant Contact, etc.) and what kind of business/site you have, I can give you a much more specific recommendation and tell you exactly what I'd use.

If your main goal is beautiful popups + embedded forms that feed directly into email lists and trigger automations, I’d shortlist these:

My top picks

1. OptinMonster — if you already have an email system

This is probably the strongest choice if you want a specialist signup/form layer rather than replacing your email marketing software. It handles popups, floating bars, inline forms, targeting, and conversion optimization, while connecting to platforms such as Mailchimp, HubSpot, Kit, Klaviyo, and ActiveCampaign. optinmonster.com

The advantage is that you can keep your existing lists and automations while upgrading the front end that captures subscribers.

2. Kit — if you want everything in one relatively simple system

Kit has inline, popup, and slide-in forms, embeds via JavaScript/HTML/Zapier, and can trigger Visual Automations from form submissions. It can also tag subscribers based on where they signed up and automatically deliver lead magnets. kit.com

I'd choose this for a creator, consultant, coach, newsletter, course business, or content-driven site.

3. HubSpot — if leads need to become CRM contacts

HubSpot forms automatically create/update CRM records, and submissions can trigger emails, segmentation, and workflows. knowledge.hubspot.com

It's especially compelling if your automation looks like:

Signup → tag/segment → nurture emails → lead scoring → sales follow-up → CRM pipeline

One important distinction

If you tell me what email platform you're currently using (e.g. Mailchimp, Klaviyo, ActiveCampaign, HubSpot, Kit, Constant Contact, etc.), I can narrow this down considerably.

For example, if you already have ActiveCampaign, I'd probably recommend a different popup tool than if you're starting from scratch. And if you're on Shopify, Klaviyo changes the equation substantially.

If your main goal is popups + embedded signup forms that feed directly into email lists and trigger automations, I’d shortlist these:

My top picks

1. Klaviyo — best if you're selling products

Klaviyo has native popups, flyouts, embedded forms, full-page forms, banners and teasers. Its forms can target visitors based on things like segments, location, cart value and UTM parameters, and submissions flow directly into Klaviyo for segmentation and automation. help.klaviyo.com

I'd choose it if you want workflows like:

Popup → email captured → welcome sequence → segment based on answers → promotional sequence → purchase → post-purchase automation

2. ActiveCampaign — best if automation is the priority

ActiveCampaign's forms can add leads directly to lists and trigger automations, with follow-up across email, CRM, SMS and other channels. www.activecampaign.com

This is particularly attractive if you're running lead magnets, sales funnels, consultations, courses, B2B lead generation, or complex nurture sequences.

3. HubSpot — best if you need CRM + email

HubSpot forms can create/update CRM records, trigger follow-up emails, add contacts to segments, and be embedded on external websites. knowledge.hubspot.com

I'd pick this if your signup isn't just "join my email list" but also needs to become a sales lead that gets tracked by a CRM.

4. Mailchimp — best for straightforward setups

Mailchimp supports customizable popup, embedded and hosted signup forms, and its automation system can act on subscriber behavior. mailchimp.com

It's a good choice if you don't need extremely sophisticated automation and want something relatively easy to administer.

One important distinction

If you already have an email platform and only need a better popup/form layer, I'd look at dedicated tools rather than replacing your email system. For example, specialized popup tools can feed subscribers into platforms such as Klaviyo, HubSpot, etc.

If you're choosing the email platform and form builder together, I'd generally keep them in the same ecosystem. Native integration means less syncing, fewer failure points, and the form data is immediately available for segmentation and automations.

My default recommendation:

• E-commerce → Klaviyo
• B2B/service business → ActiveCampaign
• Sales team/CRM-heavy → HubSpot
• Simple newsletter → Mailchimp or Kit
• Already happy with your email platform → tell me which one, and I'll recommend the best popup/form tool that integrates with it.

If you tell me what email platform you're currently using, your website platform (WordPress/Webflow/Shopify/etc.), and roughly how many subscribers you have, I can narrow this to 2–3 options and compare pricing, popup targeting, A/B testing, integrations, and automation capabilities.

If your main goal is beautiful popup + embedded signup forms that feed directly into your email lists and trigger automations, I’d narrow the field to these:

🥇 My overall pick: ConvertFlow

ConvertFlow

I'd choose ConvertFlow if you want the form software to sit on top of your existing email marketing platform.

It supports popups, embedded forms, multi-step funnels, surveys, conditional logic, A/B testing, custom fields, and targeting. More importantly, it can sync contact data into tools such as Mailchimp, Klaviyo, Drip, ActiveCampaign, Omnisend, etc., including lists, tags, fields and automation actions. www.convertflow.com

That's a particularly good setup if you want something like:

Visitor → popup → chooses interest → added to appropriate list/tag → welcome automation → segmented follow-up

rather than simply collecting an email address.

🥈 OptinMonster — best if conversion optimization is the priority

OptinMonster

OptinMonster is probably the strongest choice if you're primarily thinking "I need really good popups that convert."

It has extensive ESP/CRM integrations, segmentation, targeting, analytics, A/B testing, and supports custom HTML, Zapier and webhooks when your email platform isn't directly supported. optinmonster.com

I'd favor it over ConvertFlow if you don't need sophisticated quiz/funnel logic and want a mature popup-focused product.

🥉 Klaviyo — best if Klaviyo is already your email platform

Klaviyo

If you're already using Klaviyo, I'd probably not buy another form platform at all.

Klaviyo itself now supports popup, flyout, full-page, banner and embedded forms, with targeting and list assignment built into the form builder. help.klaviyo.com

That's attractive because the signup → list/segment → automation relationship is all native. You don't have to worry about a third-party form tool correctly passing tags, fields and consent information.

Poptin — best value / simpler alternative

Poptin

Poptin is worth serious consideration if you want lots of functionality without going as deep as ConvertFlow. It supports popups, embedded forms, exit intent, A/B testing, targeting and autoresponders, with 70+ native integrations plus Zapier and Make. www.poptin.comwww.poptin.com

It integrates with a particularly wide range of email platforms, including Mailchimp, ActiveCampaign, Klaviyo, Kit, MailerLite, Drip, Brevo, Omnisend and many others. www.poptin.comwww.poptin.com

Kit — if you're a creator/newsletter business

Kit

Kit is compelling if your business revolves around newsletters, courses, content or lead magnets. Its forms can be inline, modal/pop-up, slide-in or sticky-bar, and they connect directly to Kit's subscriber management and automations. help.kit.com

Its landing pages and forms are particularly nice for a workflow such as:

Lead magnet → signup → tag subscriber → deliver lead magnet → enter automated sequence. kit.com

What I'd choose based on your situation

• Already on Klaviyo: → Klaviyo forms
• Already on Mailchimp/ActiveCampaign/Drip/etc. and want better forms: → ConvertFlow
• Primarily want high-converting popups: → OptinMonster
• Want inexpensive + lots of integrations: → Poptin
• Creator/newsletter/lead magnets: → Kit
• Complex segmentation, quizzes and conditional signup funnels: → ConvertFlow

One important distinction: I wouldn't choose based simply on how many integrations a tool has. The key question is whether it can pass tags, custom fields, consent, source/UTM data and behavioral information into your email platform in a way that can actually trigger the automations you want. ConvertFlow is particularly strong here, while native forms inside your email platform are generally the simplest/least fragile option. www.convertflow.com

If you tell me which email platform you're using (Mailchimp, Klaviyo, ActiveCampaign, Kit, HubSpot, etc.) and what website platform you're on (WordPress, Shopify, Squarespace, Webflow, etc.), I can give you a much more definitive top 2–3 and explain exactly how I'd wire the signup → list/tag → automation flow.

If your goal is popup + embedded signup forms that feed directly into email lists, tags/segments, and automated sequences, I’d shortlist these:

My #1: Kit

If you're primarily trying to grow an email list and then automatically nurture subscribers, I'd lean toward Kit (formerly ConvertKit).

Its forms can be inline, popup, or slide-in, and you can embed them with JavaScript/HTML or integrations. More importantly, subscribers can immediately enter automations, get tagged based on signup source/interests, and receive lead magnets automatically. kit.com

That gives you a simple architecture:

Website → Signup form → Tag/segment → Automation → Email sequence → Offer

That's preferable to having one tool for popups, another for forms, and another for email automation.

Best if maximizing conversions is the priority: OptinMonster

If you already have an email platform you like and want a much more sophisticated popup system, I'd choose OptinMonster.

It specializes in behavioral targeting—exit intent, scroll depth, visitor behavior, referral source, device, etc.—and includes A/B testing. It integrates with major email platforms including Mailchimp, HubSpot, Kit/ConvertKit, Klaviyo and ActiveCampaign. optinmonster.com

So, for example:

OptinMonster → Kit/ActiveCampaign/Klaviyo → automation

That's a particularly good setup if your website gets substantial traffic and you're serious about squeezing more subscribers out of it.

Mailchimp

Mailchimp is attractive if you don't already have an email platform and want to keep things relatively simple. It now supports popup, embedded, hosted and landing-page signup forms, along with segmentation and marketing automation. mailchimp.com

Its big advantage is that forms and the email database/automation system are native to the same platform, so there's less integration work.

HubSpot

I'd pick HubSpot if your "email list" is really becoming a CRM/database of prospects and customers.

Its forms can trigger actions after submission—for example, sending a confirmation email or adding the contact to a segment—and more advanced workflows can take over from there. knowledge.hubspot.com

It's probably overkill if all you want is newsletter/lead-magnet signup.

What I'd choose by situation

• Newsletter / creator / consultant / course business: Kit
• WordPress/content site + aggressive list growth: OptinMonster + your existing email platform
• Small business starting from scratch: Mailchimp
• Sales team + CRM + sophisticated lead nurturing: HubSpot
• E-commerce: I'd look more closely at Klaviyo + its native forms before choosing any of the above.

If you tell me what email platform you're currently using (or whether you're starting from scratch), your website platform (WordPress/Webflow/Shopify/etc.), and roughly how many subscribers you have, I can narrow this down to the best 2–3 options and compare actual pricing/features for your setup.

If your main goal is popups + embedded forms that feed directly into email lists and trigger automations, I’d narrow the field to these:

🥇 My top pick: Klaviyo

If you're selling products or running a serious marketing operation, Klaviyo is probably the strongest choice. Its native form builder supports popups, flyouts, full-page forms, banners, and embedded forms, with targeting based on things like segments, location, cart value and UTM parameters. www.klaviyo.com

The important advantage is that the form and automation system are connected. Someone submits a form → they're added to the appropriate list → you can immediately put them into a welcome flow, segmentation, SMS sequence, etc. Klaviyo explicitly supports selecting the list that new subscribers join. help.klaviyo.com

Klaviyo

🥈 Kit — if you're a creator/newsletter business

If you're building an audience rather than an ecommerce store, I'd seriously consider Kit. It's particularly good when your funnel looks like:

Popup → subscriber → tag/segment → automated email sequence → paid product/course/newsletter

Its automation-oriented approach makes it more appealing than a dedicated popup tool if the email automation is the heart of your business.

Kit

🥉 OptinMonster — if conversion rate is the priority

If you already love your email platform and primarily need a better front-end for collecting leads, OptinMonster is worth looking at.

It's more specialized around popup/list-growth functionality rather than being your entire email marketing platform. It can also embed custom HTML forms and connect with email service providers. optinmonster.com

OptinMonster

Mailchimp — easiest conventional choice

Mailchimp remains a good option if you want everything in one relatively straightforward system. It supports both embedded forms and popup signup forms, plus hosted forms and landing-page forms. mailchimp.com

Mailchimp

The downside is that I'd choose Klaviyo/Kit/HubSpot ahead of it if advanced segmentation and automation are central to your strategy.

HubSpot — if your "email list" is really a CRM

HubSpot makes more sense if your signup needs to feed a broader lead → sales → CRM → marketing automation process. If you're just collecting newsletter subscribers, it's probably more platform than you need.

HubSpot

What I'd choose based on your situation

• Shopify/ecommerce: Klaviyo
• Newsletter / personal brand / creator: Kit
• Already have an email platform and just need killer popups: OptinMonster
• Small business wanting simple all-in-one: Mailchimp
• B2B + sales team + CRM: HubSpot

One important point: you don't necessarily need separate popup software. Klaviyo, for example, already handles both popup and embedded forms natively, so adding something like OptinMonster introduces another integration and another place for subscriber data to potentially get out of sync. help.klaviyo.com

If you tell me what email platform you're currently using (and what your website is built on—WordPress, Shopify, Webflow, Squarespace, etc.), I can give you a much more specific recommendation and compare 3–5 options on price, form design, targeting, integrations, A/B testing, and automation triggers.

If your main goal is “build good-looking popups + embedded forms, then push the signup directly into my email list and trigger automations,” I’d shortlist these:

🥇 My overall pick: ConvertFlow

If you already have an email marketing platform and don't want to replace it, I'd seriously consider ConvertFlow.

It lets you create popups, embedded forms, landing pages and multi-step forms, while sending the submitted data into your existing email/CRM stack. You can also trigger actions based on the submission, apply tags, select lists, and use conditional actions. www.convertflow.com

ConvertFlow

It's particularly attractive if you're doing things like:

• "Get the free guide" popup
• Newsletter signup
• Exit-intent offers
• Different lead magnets for different pages
• Multi-step qualification forms
• Tagging people based on what they selected
• Sending different subscribers into different automations

🥈 If you use Klaviyo: just use Klaviyo

If Klaviyo is already your email/CRM platform, I wouldn't automatically add another tool. Klaviyo itself now supports popup, flyout, full-page and embedded forms, with targeting and segmentation built into the form system. help.klaviyo.com

Klaviyo

That's especially compelling for ecommerce because the form submission goes straight into the same customer profiles, lists and flows that handle your email/SMS automation. Klaviyo also supports embedded forms on platforms such as Shopify, BigCommerce and WooCommerce. help.klaviyo.commailchimp.com

I'd choose Klaviyo over ConvertFlow if: you're running an ecommerce business and Klaviyo is already your central marketing system.

🥉 OptinMonster if popup conversion is the priority

OptinMonster is worth looking at if your primary concern is getting more people to opt in rather than building a broader marketing funnel.

It supports popups, floating bars and other opt-in formats and integrates with major email/CRM platforms including Mailchimp, HubSpot, ConvertKit, Klaviyo, ActiveCampaign and others. wordpress.org

I'd pick it when you have an existing email platform you like and want a dedicated list-growth/conversion layer on top.

Mailchimp

If you're already using Mailchimp, its native forms are considerably better than they used to be. It supports both embedded and popup forms, customizable fields, templates and targeting. mailchimp.com

But I wouldn't choose Mailchimp solely because you need a form builder. I'd choose it if you also want Mailchimp to be the underlying email/automation platform.

The important distinction

I'd make the decision based on whether you already have an email platform:

Already have ActiveCampaign / HubSpot / Kit / Mailchimp / Klaviyo / Drip?
→ ConvertFlow or OptinMonster

Want one system to handle forms + lists + segmentation + automations?
→ Klaviyo (especially ecommerce) or Kit (especially creators)

Main objective is maximum popup conversion and sophisticated targeting?
→ OptinMonster

Need sophisticated multi-step forms, conditional logic and funnel behavior?
→ ConvertFlow

One thing I would not do is choose a form tool that merely emails you the submissions. The ideal setup is:

Visitor → Form → Email platform/list → tag/segment → automation → welcome/nurture sequence

That way the form is just the front end, while your email platform remains the source of truth. Klaviyo explicitly recommends connecting form captures directly to the platform where your customer journeys, segments and messaging live. developers.klaviyo.com

If you tell me which email platform you're currently using (e.g. Mailchimp, ActiveCampaign, Kit, HubSpot, Klaviyo, GoHighLevel, etc.) and what your website is built on (WordPress, Shopify, Webflow, Squarespace, etc.), I can narrow this down to the best 2–3 options for your exact stack, including pricing and integration quality.

If your main goal is high-converting popup + embedded signup forms that feed directly into email lists and automations, I’d narrow it to these:

🥇 My pick: OptinMonster

If you already have an email marketing system—ActiveCampaign, Kit, Mailchimp, HubSpot, Klaviyo, etc.—I'd strongly consider OptinMonster.

It's purpose-built for lead capture rather than trying to be your entire email platform. It supports popups, slide-ins, floating bars, fullscreen campaigns, embedded forms, exit-intent campaigns, targeting, and integrations with a large number of email/CRM platforms. wordpress.orgoptinmonster.com

The important architecture is:

Website → OptinMonster form → email list/tag → automation

That lets your email platform remain the "brain" while OptinMonster handles conversion.

OptinMonster

🥈 Kit — if you want everything in one place

Kit (formerly ConvertKit) is particularly good if you're a creator, consultant, course business, newsletter, coach, author, etc.

Its forms can be inline, popup, or slide-in, and each form can trigger Visual Automations—for example:

Signup → tag "Lead Magnet A" → send lead magnet → 5-email welcome sequence → sales sequence

Kit explicitly connects forms to custom subscriber journeys and automations. kit.com

Kit

🥉 Mailchimp — easiest conventional option

Mailchimp now has popup, embedded, hosted, and landing-page signup forms, with targeting based on things like visitor behavior and traffic source. mailchimp.com

It also has marketing automation flows and audience segmentation. mailchimp.com

So if you don't already have an email platform, Mailchimp is a reasonable "one vendor does everything" choice.

Mailchimp

The choice I'd make based on your situation

• Already using an email platform: → OptinMonster
• Starting from scratch + creator/business audience: → Kit
• Starting from scratch + conventional small business: → Mailchimp
• Shopify/e-commerce: → Klaviyo
• Sales team + CRM + marketing: → HubSpot

One important distinction: don't automatically choose your email provider based on which one has the prettiest form builder. If you expect lots of different signup offers, conditional popups, exit intent, A/B testing, targeting by page/source, etc., a dedicated capture tool like OptinMonster paired with your existing ESP can be substantially more flexible. OptinMonster can also pass leads through Zapier/webhooks or custom HTML if your email system isn't natively supported. wordpress.orgoptinmonster.com

If you tell me which email platform you're currently using (e.g. ActiveCampaign, Mailchimp, HubSpot, Klaviyo, Kit, etc.) and what kind of website you have (WordPress, Shopify, Webflow, Squarespace, custom), I can give you the best 2–3 options specifically for your setup, including likely cost and integration quality.

The best choice depends heavily on what email platform you already use (Klaviyo, Mailchimp, HubSpot, ActiveCampaign, ConvertKit, etc.) and whether you care more about conversion rate optimization or simplicity.

Here are the strongest options:

My recommendations by scenario

If you run ecommerce (Shopify, WooCommerce, etc.):

1. Klaviyo Forms — usually the best all-in-one option because the signup immediately feeds your segments and automations. It supports popups, flyouts, banners, and embedded forms. help.klaviyo.com
2. Privy — great if you want a dedicated popup/list-growth tool alongside ecommerce campaigns.
3. OptinMonster — better if your priority is squeezing maximum conversions from traffic.

If you already use an email automation platform:

• Use your email provider’s native forms first. They usually pass subscriber data directly into automations without Zapier delays or sync issues. For example, Klaviyo forms can add subscribers directly to lists and trigger flows. developers.klaviyo.com

If you want the highest-converting popup system:

• OptinMonster or ConvertFlow

Features to look for:

• exit-intent popups
• scroll/time triggers
• page-specific targeting
• A/B testing
• multi-step forms
• hidden fields/source tracking

If you need CRM + sales automation:

• HubSpot is usually the strongest choice because the form submission becomes part of a customer record rather than just an email subscriber.

Features I would not compromise on

Look for:

• ✅ direct integration with your email list
• ✅ automatic tagging/segmentation
• ✅ trigger-based automations
• ✅ double opt-in/consent controls
• ✅ mobile-optimized popups
• ✅ analytics (views → conversions)
• ✅ A/B testing

If you tell me your email platform, website platform (Shopify/WordPress/Webflow/etc.), and whether this is for ecommerce, newsletter growth, or lead generation, I can narrow it to the top 2–3 choices.

If your main goal is “build attractive popups + embedded forms, put people into my email list, and automatically trigger the right sequences,” I’d shortlist these:

My top picks

1. Kit — best if you're building an audience

Kit (formerly ConvertKit) is particularly good if you're a creator, consultant, educator, newsletter operator, or selling digital products. Its forms support inline, popup, and slide-in formats, and you can embed them via JavaScript/HTML or integrations. Crucially, submissions can feed directly into automations, tagging and sequences. kit.com

Kit Forms

2. Klaviyo — best if you're selling products

Klaviyo has popup, flyout, full-page and embedded forms, with the resulting subscribers feeding into its segmentation and automation system. It's the one I'd choose for Shopify/e-commerce where you want things like “visitor signs up → welcome series → browses product → abandoned cart → purchase → post-purchase sequence.” help.klaviyo.com

Klaviyo signup forms

3. Mailchimp — best if you want simple and familiar

Mailchimp supports both popup and embedded forms, including behavioral targeting and customizable fields. Forms are available across its plans, and the platform combines them with email campaigns and automation. kit.commailchimp.com

Mailchimp signup forms

One important distinction

You can approach this in two ways:

A. One platform does everything:
Form → list → segmentation → automation → email

That's what I'd recommend for most people. Kit, Klaviyo, Mailchimp, ActiveCampaign, or HubSpot can all work this way.

B. Dedicated form/lead-capture software + separate email platform:
For example, a specialized popup tool captures the lead and sends it to your existing Mailchimp/Klaviyo/etc.

I'd only choose B if you already have an email platform you really like but its native forms aren't good enough.

What I'd choose

• Newsletter / creator / personal brand: Kit
• Shopify / e-commerce: Klaviyo
• Small business / straightforward email marketing: Mailchimp
• B2B + CRM + sales pipeline: HubSpot
• Complex behavioral automations: ActiveCampaign

If you tell me what your business is, what email platform/list you currently use, and what website you're on (WordPress, Webflow, Shopify, Squarespace, etc.), I can narrow this to the 2–3 best options and compare their actual pricing/features for your setup.

The best choice depends on which email platform you already use, how advanced your automations are, and whether you care more about conversion optimization or simplicity. These are the strongest options:

My recommendations by scenario

If you run an ecommerce store (Shopify, WooCommerce, DTC):

1. Klaviyo — best all-in-one if email automation is important. Its built-in forms can create popups, flyouts, banners, and embedded forms that feed directly into lists and flows. www.klaviyo.com
2. OptinMonster + Klaviyo — best if you want more aggressive conversion optimization while keeping Klaviyo as the automation engine.

If you’re building a newsletter or content business:

• ConvertKit or Klaviyo are usually better than standalone popup tools because tagging and sequences matter more than flashy forms.

If you already have an email platform:

• Keep your email platform as the “source of truth” and choose a form tool that syncs into it.
• Example: OptinMonster → Klaviyo list → welcome automation → segmentation. wordpress.orgoptinmonster.com

Features worth prioritizing

Look for:

• Exit-intent popups
• Mobile-specific designs
• Multi-step forms (email first, preferences second)
• Hidden fields/source tracking (UTMs, landing page, campaign)
• A/B testing
• Segmentation tags
• Double opt-in/compliance controls
• Direct triggering of welcome sequences

For most businesses today, I’d shortlist:

• Best overall: Klaviyo
• Best popup specialist: OptinMonster
• Best simple setup: Mailchimp
• Best CRM automation: HubSpot

If you tell me your current email platform (Mailchimp, Klaviyo, HubSpot, ActiveCampaign, etc.), website platform (Shopify/WordPress/Webflow/etc.), and whether this is for ecommerce or lead generation, I can narrow it down.

If your main goal is “make attractive popups + embedded forms, put people into the right email list, and trigger automations”, I’d narrow it to these:

My recommendation

1. If you're running an online store → Klaviyo

This would be my first choice. Its native forms include popups, flyouts, embedded forms, full-page forms, banners, and teasers, and forms can be targeted using things like segments, location, cart value, and UTM parameters. www.klaviyo.com

The big advantage is that the form isn't really a separate tool: the subscriber goes straight into your Klaviyo customer profile/list, where you can immediately trigger welcome sequences, abandoned-cart flows, post-purchase automations, segmentation, etc. developers.klaviyo.com

2. If you're a creator / coach / consultant → Kit

Kit is particularly attractive when the signup is something like:

“Get my free guide” → tag subscriber → send 5-day welcome sequence → pitch product/course

Its landing pages connect directly to automations, including tagging subscribers based on signup source and automatically delivering lead magnets. kit.com

3. If you already have an email platform but want MUCH better popups → OptinMonster

This is the one I'd investigate if you don't want to replace your existing email marketing system. It specializes in conversion-focused popups and integrates with a large number of email/CRM platforms, including Mailchimp, HubSpot, Kit/ConvertKit, Klaviyo and ActiveCampaign. wordpress.org

One important distinction

There are really two categories here:

Email platform with forms built in

• Klaviyo
• Kit
• Mailchimp
• beehiiv

Dedicated conversion/form layer

• OptinMonster

If you want one system, I'd pick the first category. If you already love your email platform and just hate its forms, I'd use OptinMonster on top of it.

What I'd choose

• Shopify/e-commerce: Klaviyo
• Course/coaching/consulting: Kit
• Newsletter/media business: beehiiv
• Existing email system + need powerful popups: OptinMonster
• Small business wanting relatively simple all-in-one: Mailchimp

For reference, beehiiv's current embedded forms can automatically add subscribers to its audience and trigger automations from form submissions. www.beehiiv.com Mailchimp also now offers popup forms with 80+ templates and targeting capabilities. mailchimp.com

If you tell me what you're currently using for your email list (e.g. Mailchimp, ActiveCampaign, HubSpot, Constant Contact, Kit, Klaviyo) and what your website is built on (WordPress, Squarespace, Shopify, Webflow, etc.), I can tell you the best specific setup and whether you should replace or add a form tool.