Most "best A/B testing tools" lists miss the question that decides which tool you should actually pick: does it work with the site you already have?
A platform that's great for a React app is often painful on WordPress. A Webflow-native tool is useless if you're on Elementor. "Enterprise-grade" often means "you'll need a developer."
We built Optibase because we kept running into this gap ourselves, and we spent the last year running tests on every major CMS and page builder to see how the rest of the market actually performs. This is the result: 13 platforms compared on pricing, setup, statistical rigor, and fit for real marketing teams.
If you're short on time:
We didn't pull this list from a category page. We installed each tool on real sites and ran tests on them.
Our criteria:
Every platform on this list was evaluated against those seven criteria. We also read recent G2 and Capterra reviews and compared them to our own hands-on findings.
Starting price: $79/mo, or $66/mo billed annually · Free plan: Yes · Best for: Marketers on WordPress, Webflow, Elementor, Divi, Bricks, Oxygen, Breakdance, and Gutenberg who want to run tests without pulling a developer into every change.
Optibase is the A/B testing platform we built because nothing on the market worked the way page builders actually work. Install it from the Webflow App Marketplace or drop the WordPress plugin in — and you're running tests in minutes. Variants are built in your existing design tool (the Webflow Designer, the WordPress editor, Elementor, Divi, whichever you're on), not in a clunky third-party visual editor that breaks on every CMS update.
What stands out:
Tradeoffs: If you're building a mobile app or a purely server-side experiment stack, Optibase isn't for you. It's purpose-built for marketing teams running tests on real websites.
See how it works on your stack: WordPress · Webflow · Elementor · Divi · Bricks · Oxygen · Breakdance · Gutenberg
G2 rating: 4.6 / 5 from 19 reviews
Starting price: from ~$314/mo · Free plan: No · Best for: Mid-market teams that want testing, heatmaps, session recordings, and surveys in one account.
VWO has been in the A/B testing market for over a decade and it shows. The platform covers almost every CRO need — testing, heatmaps, funnels, surveys, personalization — in one interface. It was one of the biggest beneficiaries of Google Optimize shutting down in 2023.
Where it shines: teams with real traffic and a dedicated CRO lead who'll use the full suite. The Bayesian stats engine is solid, and the feature set runs deep.
Where it struggles: pricing and speed. Published pricing now starts around $314/mo and scales with monthly tracked users, so most B2B sites land meaningfully higher than the entry number suggests. Setup involves pasting a script and wiring up integrations, which is not the 10-minute install Optibase offers. WordPress and page-builder support exists but feels bolted on.
Read the full Optibase vs. VWO comparison →
Starting price: Custom, typically around $36K+/yr · Free plan: No · Best for: Enterprise product and growth teams with dedicated experimentation engineers.
Optimizely is the most recognizable name in A/B testing. If you work at a public company with a team of optimizers and engineers, it's a defensible choice — the stats engine is best-in-class and the platform scales to billions of events.
Where it shines: omnichannel experimentation (web, mobile, server-side, feature flags), enterprise compliance, and deep analytics. Their AI assistant helps with variant ideas.
Where it struggles: price and complexity. Optimizely does not publish prices. Quotes vary with traffic and which products you take, and the commonly cited starting point is around $36,000/year on an annual commitment. The platform assumes a dedicated team, so marketers without engineering support will feel lost. For anyone outside the Fortune 1000, it is almost always overkill.
Read the full Optibase vs. Optimizely comparison →
Starting price: Custom · Free plan: No · Best for: Mid-market and enterprise marketing teams that want personalization on top of A/B testing.
AB Tasty blends experimentation with a strong personalization engine. If your goal is "show different content to different segments and test what works," it's a legitimate contender.
Where it shines: segmentation, personalization rules, and emotional intelligence targeting (yes, that's a real feature — it infers intent from behavior). Good visual editor, good support.
Where it struggles: pricing is opaque. You can't get a number without a call, and once you do, expect mid-four figures per month minimum. Teams on WordPress or page builders won't find native integrations — everything runs through their JS snippet.
Read the full Optibase vs. AB Tasty comparison →
Starting price: $399/mo · Free plan: No · Best for: Agencies and teams with strict GDPR or data-ownership requirements.
Convert is the go-to choice for teams that care deeply about privacy. It has first-party tracking, EU data hosting, and an agency-friendly billing model.
Where it shines: GDPR compliance, honest support, and a stats engine respected by CRO consultants. The community around it is small but loyal.
Where it struggles: price to value. At $399/mo starting, it sits in premium territory without the full CRO suite that VWO offers at a similar price. No built-in heatmaps — you'll integrate with Hotjar or another tool. Setup takes longer than the faster no-code options.
Read the full Optibase vs. Convert comparison →
Starting price: Custom · Free plan: No · Best for: Mid-market to enterprise teams that want AI-generated variants and predictive targeting.
Kameleoon has invested heavily in AI. Their platform can generate variant copy, predict which visitor will convert, and auto-allocate traffic to the winning version.
Where it shines: AI variant generation, predictive personalization, and a genuinely polished visual editor. Solid in both web and full-stack testing.
Where it struggles: custom pricing (expect enterprise quotes), and the AI features only matter if you have enough traffic to feed them. Teams under 100,000 monthly visitors won't get the full value.
Read the full Optibase vs. Kameleoon comparison →
Starting price: Free up to 1M requests/mo, then pay-as-you-go · Free plan: Yes · Best for: Product engineers who want analytics, feature flags, session replay, and testing in one open-source stack.
PostHog bundles product analytics, session replay, feature flags, and A/B testing in a single platform. For product-led startups and scaleups, it's one of the best deals on the market.
Where it shines: generous free tier (1M feature flag requests/mo), both Bayesian and frequentist stats, and the open-source ethos. Everything talks to everything else.
Where it struggles: this is a developer tool. There's no drag-and-drop visual editor for marketers. Setting up a web A/B test requires writing code to gate variants behind a feature flag. If your team is non-technical, expect friction.
Read the full Optibase vs. PostHog comparison →
Starting price: Free self-hosted (MIT) · Free plan: Yes (3 users cloud) · Best for: Data and engineering teams that already have a data warehouse.
GrowthBook is built around the idea that your warehouse is the source of truth. Instead of sending user data to a third-party tool, GrowthBook queries your BigQuery, Snowflake, or Redshift directly.
Where it shines: open-source (MIT license), warehouse-native architecture, both Bayesian and frequentist stats with CUPED variance reduction, multi-arm bandits on the Pro plan ($40/user/mo).
Where it struggles: not a marketer tool. If you don't have a warehouse or a data engineer, it's the wrong choice. The visual editor exists on the Pro plan but lags behind dedicated web testing tools.
Starting price: Free tier + usage-based pricing · Free plan: Yes · Best for: Product and engineering teams that need feature flags and experimentation in the same platform.
Statsig was founded by ex-Facebook experimentation engineers. It's the closest thing to a "Facebook-style" experimentation platform available to everyone else.
Where it shines: feature flag + experimentation integration, fast evaluation, strong stats including sequential testing. Free tier is generous.
Where it struggles: same issue as PostHog — this is engineering software. Marketing teams running tests on WordPress or Webflow pages will find it heavy-handed.
Starting price: $99/mo for Plus, the cheapest tier that includes A/B testing · Free plan: No · Best for: Early-stage teams that want light A/B testing and heatmaps in one tool.
Crazy Egg pioneered heatmaps and has since bolted on A/B testing. The $29/mo Starter plan covers heatmaps and recordings only, so A/B testing starts at $99/mo on Plus. All plans are billed annually.
Where it shines: price, simplicity, and the heatmap-to-test workflow — you see where people click, then test a fix.
Where it struggles: the testing engine is shallow. Frequentist-only stats, no server-side, limited segmentation, no Bayesian "call it" guidance. Fine for one or two tests a quarter; painful at scale.
Starting price: $149/mo, or $112/mo billed annually · Free plan: No · Best for: Paid-ads teams running dedicated landing pages outside their main CMS.
Unbounce isn't really an A/B testing platform — it's a landing page builder with A/B testing built in. For teams running Google or Facebook ads to dedicated landing pages, it covers the full workflow.
Where it shines: fast landing page creation, Smart Traffic (their AI sends visitors to the best-performing variant automatically), and AMP templates for mobile speed.
Where it struggles: it only tests Unbounce pages. You can't use it to A/B test your WordPress homepage, your Webflow pricing page, or your app's signup flow. Single-purpose.
Starting price: from €249/mo (€199/mo billed annually) · Free plan: Yes · Best for: European marketing teams who want a clean no-code editor and GDPR compliance without an enterprise contract.
Varify is a German tool built for marketers. The visual editor is clean, setup is quick, and GDPR compliance is handled out of the box rather than bolted on.
Where it shines: straightforward no-code editing, EU data handling, and flat pricing that does not scale with your traffic.
Where it struggles: no heatmaps, no session recordings, and fewer integrations than the bigger suites. It used to be the budget pick, but at €249/mo it now sits above tools that include behaviour analytics at the same price.
Read the full Optibase vs. Varify comparison →
Starting price: $379/mo, or $299/mo billed annually, for 25,000 page views · Free plan: No · Best for: Webflow teams who want testing from Webflow itself and are comfortable paying per page view.
Webflow Optimize is Webflow's native A/B testing feature. It's built into the Designer and integrates cleanly with Webflow's hosting stack.
Where it shines: no third-party script, tight Webflow integration, decent visual editor (it is the Designer).
Where it struggles: price and scope. Pricing is per page view, so cost climbs with traffic, and the self-serve plan caps you at five concurrent optimizations. There are no heatmaps or session recordings, and it only works on Webflow. If you run WordPress or a page builder anywhere in your stack, it cannot help you there.
Read the full Optibase vs. Webflow Optimize comparison →
Short answer: No, GA4 cannot run A/B tests · What it can do: Report on a test another tool is running · Free routes instead: PostHog's free tier, GrowthBook self-hosted, or the Optibase free plan.
This is the question we get asked most often, so it is worth answering plainly. Google Optimize, the free tool most teams used, shut down on 30 September 2023, and Google did not replace it. GA4 has no built-in way to split traffic, assign visitors to variants, or build a variant. There is no "GA4 Experiments" feature to turn on.
What GA4 is good for: measurement. If your testing tool sends experiment data into Analytics, GA4 is a solid place to analyse the outcome against the rest of your funnel. Google also publishes APIs that testing platforms use for exactly this.
What you still need: a real testing tool to run the test. If "free" is the requirement, PostHog's free tier and GrowthBook self-hosted both work but need a developer, and the Optibase free plan covers 10,000 tested users a month without one. Read the limits on any free plan before you build a programme on it. Firebase A/B Testing is a separate product for mobile apps, not a GA4 feature for websites.
Pick the tool that matches your setup, not the one with the biggest name. Five questions will get you to the right answer:
If it's WordPress, Webflow, or a page builder, pick a tool that's native to that stack. Enterprise tools work eventually on WordPress, but the setup will frustrate you for weeks. See our platform-specific guides for WordPress, Webflow, Elementor, Divi, Bricks, Oxygen, Breakdance, and Gutenberg.
If no, rule out Optimizely, PostHog, Statsig, and GrowthBook. They're powerful but assume engineering support. Go with Optibase, VWO, or Convert.
Under 50,000 visitors/month, enterprise tools are overkill. Stick to the $79 to $200/mo tier. Over 500,000, your stats will be stronger and enterprise tools start to pay off.
If yes, you're looking at Statsig, PostHog, GrowthBook, or Optimizely Full Stack. If no (most marketing teams), don't pay for them.
If you hate "contact sales," skip Optimizely, AB Tasty, and Kameleoon. Optibase, VWO, Convert, and the open-source tools all publish prices.
Still unsure? The safe default for most marketing teams on WordPress, Webflow, or a page builder is Optibase. It's what we built the product for.
Even the best platform won't save a poorly designed test. Five traps we see constantly:
If you stop a test the moment one variant looks like a winner, you're often reading noise. Use a duration calculator before you launch to know how long you need to run.
You need a minimum number of visitors and conversions to trust the result. Our sample size calculator tells you what you need before you start.
If you change the headline, button, and image in one variant, you can't tell which change moved the needle. Either isolate one change per variant, or use real multivariate testing with a tool that can handle it.
If visitors see the original content for a split second before the variant loads, two bad things happen — they notice it (bad UX) and your result is biased toward the variant they saw longest. Pick a platform with zero-flicker rendering.
"Clicks on the hero button" is not a goal — it's a metric. Tie every test to an outcome that matters: paid signups, demo requests, revenue.
The landscape looks different than it did three years ago. Five things worth knowing:
The free incumbent shut down September 30, 2023, and Google never shipped a replacement. GA4 cannot run tests on its own, so most teams migrated to VWO, Optibase, or Convert.
Kameleoon, Optimizely, and VWO all ship AI features that generate variant copy, predict winners, or auto-allocate traffic. Treat these as helpful shortcuts, not magic — the quality of the underlying test still depends on your hypothesis.
Product teams want to test code changes, not just CSS. Tools like PostHog, Statsig, and GrowthBook have made server-side experimentation accessible. For marketing tests on websites, client-side is still the right choice.
In the EU, consent mode v2 changed how you can collect data for experiments. Tools with first-party tracking (Convert, Optibase) handle this more cleanly than those relying on third-party cookies.
Frequentist stats (p-values, "95% significance") still dominate but Bayesian approaches are more intuitive for marketers — "there's an 87% probability variant B beats A" is easier to act on. Most modern platforms now offer both.
An A/B testing platform lets you show two or more versions of a page or element to different visitors and measure which version drives more conversions. A good platform handles traffic splitting, statistical analysis, and reporting so you can run tests without building the infrastructure yourself.
For most WordPress sites, Optibase is the fastest to set up and the cheapest full-featured option. It installs as a plugin, doesn't require code, and works across all major page builders. See our WordPress A/B testing guide for the full setup.
Optibase is the only A/B testing tool that lives inside Webflow's App Marketplace. One-click install, variants built in the Designer, zero flicker. Webflow Optimize is the first-party alternative: it is a paid add-on on any paid Site plan, priced per page view from $299/mo billed annually. See our Webflow guide for the full breakdown.
No. Google Optimize shut down on September 30, 2023 and Google did not ship a replacement inside GA4. GA4 can report on a test that another tool runs, but it cannot split traffic or build variants itself. Teams that relied on Optimize mostly migrated to VWO, Optibase, or Convert.
Not with a tool built for marketers. Optibase, VWO, Crazy Egg, Varify, and Unbounce all let you build tests without writing code. Optimizely, PostHog, Statsig, and GrowthBook all assume some developer involvement.
Pricing ranges widely. Marketer-focused tools start at $79/mo (Optibase) to $99/mo (Crazy Egg Plus). Mid-market platforms run $300 to $400/mo (VWO, Convert, Varify). Webflow Optimize is priced per page view from $299/mo. Enterprise platforms are custom-quoted and usually land in the tens of thousands per year (Optimizely, AB Tasty, Kameleoon).
A/B testing compares two versions with one change between them. Multivariate testing compares multiple changes at once and tells you which combination wins. Use A/B for clear, single-hypothesis tests. Use multivariate when you have enough traffic to test combinations.
Yes, though fewer than you would hope. PostHog has a free tier, GrowthBook is free if you self-host, and Optibase has a free plan covering 10,000 tested users a month. Google Optimize was the free standard until it shut down in September 2023, and GA4 does not replace it: it has no native way to run or split a test. Read the limits on any free plan before you commit.
Bayesian tells you "the probability B beats A is X%." Frequentist tells you "this result is statistically significant at the 95% level." Bayesian is easier to interpret mid-test. The best platforms (Optibase, PostHog, GrowthBook, Optimizely) support both.
Flicker happens when visitors see the original content for a moment before the variant loads. It hurts UX and biases your results. Pick a platform with first-render variant injection. Optibase, VWO, and Convert all render flicker-free by default. Most cheaper tools don't.
Optibase is built for the way modern marketing teams actually work — on WordPress, Webflow, and every page builder that matters. Install in minutes. Launch your first test today. No credit card needed.
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