A/B testing is where opinions go to die — if the statistics are sound. Since Google Optimize shut down in 2023, the category has split between developer-first experiment platforms and marketer-friendly CRO suites. Our top pick is PostHog, with an SR Score of 88, because it folds experiments and feature flags into an analytics platform with a large free tier, so the data and the test live together. For marketing teams who want a visual editor and mature CRO tooling, VWO (86) is the runner-up. Enterprises still default to Optimizely.
The ranking
| Rank | Tool | Best for | Entry price | SR Score |
|---|---|---|---|---|
| 1 | PostHog | Experiments + flags + analytics | Free to 1M events | 88 |
| 2 | VWO | Visual-editor CRO testing | ~$314/mo (10k MTUs, annual) | 86 |
| 3 | Optimizely | Enterprise experimentation | Custom ($25k–$150k+/yr) | 84 |
| 4 | AB Tasty | Testing + personalization | Custom ($35k–$70k+/yr) | 82 |
| 5 | Crazy Egg | Budget A/B + heatmaps | Standard $49/mo (annual) | 80 |
| 6 | Matomo | Privacy-first A/B testing | Plugin ~€249/yr (self-hosted) | 79 |
| 7 | Amplitude | Experimentation + analytics | Free / Growth custom | 78 |
Methodology
The Tool Score v2026 rubric weights five criteria summing to 100:
- Statistical rigor (30) — significance methods (frequentist/Bayesian/sequential), sample-size guidance, peeking protection.
- Capability & editor (25) — visual editor, server-side testing, multivariate, personalization, flags.
- Value for money (20) — cost at a realistic traffic/MTU level.
- Integrations & support (15) — analytics tie-in, CDP/data connectors, onboarding.
- Transparency (10) — published pricing, clear methodology.
Statistical rigor leads because an underpowered or peeked test produces confident nonsense. Re-weight toward Capability/editor and VWO and AB Tasty climb; toward Value and PostHog and Crazy Egg win.
PostHog
Experiments built into a full analytics platform with feature flags, so you test, flag, and measure in one place. Free to 1M events/month (and 1M flag requests), usage-based past that. Frequentist and Bayesian results, with experiments tied directly to product events. Best for engineering-led teams.
| Criterion | Score |
|---|---|
| Statistical rigor | 25/30 |
| Capability & editor | 23/25 |
| Value for money | 18/20 |
| Integrations & support | 12/15 |
| Transparency | 8/10 |
Trade-off: no polished visual editor for non-technical marketers; experiments lean developer-first.
VWO
The CRO suite with a strong visual editor. VWO publishes a starting price around $314/month (billed annually) for up to 10,000 MTUs on the Testing module; at 100,000 MTUs the Growth plan runs roughly $665/month annually. A/B, split-URL, and multivariate testing with Bayesian stats. Note VWO is discontinuing its free Starter plan in 2026 in favor of a 30-day trial.
| Criterion | Score |
|---|---|
| Statistical rigor | 26/30 |
| Capability & editor | 24/25 |
| Value for money | 16/20 |
| Integrations & support | 13/15 |
| Transparency | 7/10 |
Trade-off: pricing scales fast with MTUs, the public pricing page is vague, and the free tier is going away.
Optimizely
The enterprise experimentation standard. Pricing is custom and unpublished; Web Experimentation standalone is commonly cited at $25,000–$40,000/year for the entry tier, climbing well past $100,000 with traffic and bundles. Robust stats engine, server-side and feature experimentation, and strong governance.
| Criterion | Score |
|---|---|
| Statistical rigor | 27/30 |
| Capability & editor | 24/25 |
| Value for money | 9/20 |
| Integrations & support | 14/15 |
| Transparency | 6/10 |
Trade-off: enterprise pricing, and crossing MTU tiers can force costly upgrades for modest traffic growth.
AB Tasty
Testing plus personalization in one platform. Custom pricing, with mid-market deployments typically $35,000–$70,000/year and a 30-day free trial. Strong visual editor, personalization, and feature management; implementation support is often a paid add-on.
| Criterion | Score |
|---|---|
| Statistical rigor | 24/30 |
| Capability & editor | 24/25 |
| Value for money | 11/20 |
| Integrations & support | 13/15 |
| Transparency | 6/10 |
Trade-off: sales-led pricing with traffic caps and overage fees; setup fees can be steep.
Crazy Egg
The budget option. A/B testing is included from the Standard plan at $49/month (annual, 75,000 pageviews), bundled with heatmaps and recordings. Simple, affordable testing for small sites that also want behavior data.
| Criterion | Score |
|---|---|
| Statistical rigor | 21/30 |
| Capability & editor | 20/25 |
| Value for money | 18/20 |
| Integrations & support | 12/15 |
| Transparency | 9/10 |
Trade-off: lighter statistical tooling and no server-side testing; pageview caps limit high-traffic use.
Matomo
Privacy-first A/B testing via the A/B Testing plugin (~€249/year self-hosted, included on some Cloud tiers). Tests run inside your own Matomo with full data ownership and cookieless operation. Best for Matomo shops with compliance priorities.
| Criterion | Score |
|---|---|
| Statistical rigor | 22/30 |
| Capability & editor | 19/25 |
| Value for money | 16/20 |
| Integrations & support | 11/15 |
| Transparency | 8/10 |
Trade-off: only sensible inside a Matomo deployment; editor and stats trail the CRO specialists.
Amplitude
Experimentation tied to deep behavioral analytics. Free Starter (10k MTUs / 2M events) with web experimentation; Plus $49/month; Growth custom adds feature experimentation and a code editor. Best when you want experiments anchored to rich product analysis.
| Criterion | Score |
|---|---|
| Statistical rigor | 24/30 |
| Capability & editor | 21/25 |
| Value for money | 14/20 |
| Integrations & support | 13/15 |
| Transparency | 7/10 |
Trade-off: full experimentation features sit on the custom Growth tier; it is an analytics platform first.
Verification
- PostHog — experiments, flags, free-tier limits verified on posthog.com/pricing and docs.
- VWO — ~$314/mo starting price, MTU scaling, free-tier discontinuation verified on vwo.com/pricing and aggregators.
- Optimizely — custom pricing and Web Experimentation estimates verified on optimizely.com/plans and market data.
- AB Tasty — custom pricing and trial verified on abtasty.com/pricing and Vendr data.
- Crazy Egg — Standard $49/mo with A/B testing verified on crazyegg.com/pricing.
- Matomo — A/B Testing plugin pricing verified on matomo.org plugin marketplace.
- Amplitude — free/Plus pricing and experimentation tiers verified on amplitude.com/pricing.
Related rankings
- Best Product Analytics Tools 2026: 7 Scored
- Best Session Replay Tools 2026: 7 Scored
- Best Conversion Tracking Tools 2026: 7 Scored
- Best Cookieless Analytics Tools 2026: 7 Scored
Frequently asked questions
- What is the best A/B testing tool in 2026?
- For product teams, PostHog bundles experiments with analytics and feature flags on a generous free tier. For marketing/CRO teams who want a visual editor, VWO and AB Tasty lead, while Optimizely is the enterprise standard. Matomo is the privacy-first pick.
- Why did Google Optimize go away?
- Google sunset Optimize in September 2023, pushing users toward GA4 plus third-party tools. That left a gap the platforms on this list filled — there is no free Google A/B testing tool anymore.
- How much traffic do I need to A/B test?
- Enough to reach statistical significance in a reasonable window — typically thousands of conversions, not just visitors. Low-traffic sites should test big changes, run tests longer, or use sequential/Bayesian methods that some tools here offer.
- What is the difference between client-side and server-side testing?
- Client-side testing changes the page in the browser via a visual editor — fast to set up but can flicker. Server-side testing renders the variant on the server — no flicker, works for back-end logic, but needs developer involvement. Several tools here do both.