I’ve run 800+ A/B tests across 50+ businesses. I’ve paid for — and cancelled — a lot of CRO tools in that time.
This is not a list of every tool that claims to be a “CRO tool.” It’s the tools I actually use, recommend to clients, and trust to give reliable data. For each one I’ll tell you what it’s genuinely good at, where it falls short, and who should use it.
The CRO Tool Stack You Actually Need
Before reviewing individual tools, here’s the minimum viable CRO stack:
- Analytics — Understand what’s happening (traffic, conversions, funnel drop-off)
- Qualitative research — Understand why it’s happening (heatmaps, session recordings, surveys)
- A/B testing — Test your hypotheses rigorously
- Feedback/voice of customer — Hear directly from users
You don’t need every tool in every category. You need one good tool per category. Start with analytics and qualitative research. Add A/B testing once you have a hypothesis backlog.
Analytics Tools
Google Analytics 4
Best for: Every website, full stop.
GA4 is free, powerful, and the industry standard. Its event-based model gives you flexibility that Universal Analytics never had. The funnel exploration reports are especially valuable for CRO — you can build a custom funnel, see drop-off at each step, and segment by device, source, or any dimension.
Where it falls short: The learning curve is steep. The default interface buries the most useful reports. You need to spend real time setting it up properly — custom conversions, funnel explorations, audience segments.
My setup: Custom conversion events for every meaningful action (not just the final purchase), funnel explorations for the top 5 user paths, weekly automated reports on key segments.
Cost: Free. No excuse not to use it.
Verdict: Use it. Full stop.
Microsoft Clarity
Best for: Heatmaps, session recordings, and Microsoft’s surprisingly powerful rage-click and dead-click analysis.
Clarity is free and has gotten remarkably good. It automatically flags sessions with rage clicks (users repeatedly clicking the same element in frustration), dead clicks (clicking non-interactive elements), and excessive scrolling. These automated insights surface problems without you having to manually dig through hundreds of sessions.
Where it falls short: Privacy concerns for some audiences (it’s Microsoft), and the session replay quality is occasionally choppy on complex single-page apps.
My setup: Installed on every client site by default. The free tier is sufficient for most businesses.
Cost: Free.
Verdict: Install it immediately. There’s no downside to having it running.
Hotjar
Best for: Teams that want a polished, integrated heatmap + session recording + survey tool.
Hotjar is the premium alternative to Clarity. The interface is cleaner, the session replay quality is better, and the built-in survey and feedback tools are excellent. The ability to trigger a user survey on exit intent, after a certain scroll depth, or after X seconds is genuinely useful — I’ve pulled some of my best conversion insights from exactly this setup.
Where it falls short: Expensive at scale. The free tier is severely limited on session recordings (35/day). For meaningful qualitative research on a high-traffic site, you’ll need a paid plan.
Cost: Free tier available. Paid plans from ~£30/month. Business plans from ~£80/month.
Verdict: Excellent tool. Use Clarity for free if budget is tight; upgrade to Hotjar when you’re ready to invest in qualitative research seriously.
A/B Testing Tools
VWO (Visual Website Optimizer)
Best for: Mid-market and enterprise businesses running a serious A/B testing program.
VWO is my go-to recommendation for clients who are serious about testing. It handles A/B tests, multivariate tests, split URL tests, and personalization campaigns all in one platform. The visual editor is solid. The stats engine uses Bayesian statistics, which is better than frequentist for most business use cases. And the heatmap and session recording features are included, which cuts down on tool sprawl.
Where it falls short: The pricing is significant — starts around $200/month and climbs quickly with traffic. The visual editor can struggle with complex JavaScript-heavy pages.
Cost: From ~$200/month (Basic). Plan pricing scales with monthly tracked users.
Verdict: Best-in-class for serious testing programs. Not worth the cost if you’re running fewer than 2–3 tests per month.
Optimizely (Web Experimentation)
Best for: Enterprise teams with developer resources and a sophisticated testing program.
Optimizely is the enterprise standard in A/B testing. It’s extremely powerful — server-side testing, feature flags, multi-page experiments, personalization at scale. Used by Google, Adobe, Microsoft, and most large-scale ecommerce brands.
Where it falls short: Very expensive. Requires technical implementation. It’s not built for small or mid-market businesses, and the pricing reflects that.
Cost: Custom pricing. Expect £20K+/year at enterprise scale.
Verdict: Best enterprise testing platform. Overkill for most businesses.
Google Optimize (Defunct — Know Your Options)
Google Optimize was shut down in September 2023. If you’re still seeing recommendations to use it, the source is outdated.
The best free alternatives:
- Optimizely’s Free plan: Very limited but genuinely free
- AB Tasty Starter: Limited free tier
- VWO’s Rollout plan: Free for feature flags, not full A/B testing
For businesses who want a genuinely good free A/B testing solution: honestly, none of the current options are fully satisfying. Budget for a paid tool or accept significant limitations.
Convert.com
Best for: Privacy-focused businesses and agencies running tests for multiple clients.
Convert is built with GDPR compliance front and centre — it’s cookie-less tracking capable and runs on first-party data. The platform is technically solid with good segment targeting and a reliable stats engine.
Where it falls short: Less polished UI than VWO. Smaller community and fewer integrations.
Cost: From ~$700/month. Primarily pitched at agencies.
Verdict: Strong choice for agencies or privacy-first use cases.
Voice of Customer / Survey Tools
Typeform
Best for: On-site surveys, exit surveys, and NPS collection.
Typeform’s conversational, one-question-at-a-time format gets dramatically higher completion rates than traditional multi-question forms. For CRO research — understanding why users aren’t converting, what’s confusing, what almost stopped them — exit surveys with Typeform are invaluable.
My most effective CRO survey question: “What was the one thing that almost stopped you from completing your purchase today?” — asked on the post-purchase confirmation page. The answers reveal objections you didn’t know existed.
Cost: Free tier available. Paid plans from £21/month.
Verdict: The best option for qualitative research surveys.
Hotjar Surveys / Feedback
Best for: Teams already using Hotjar who want surveys and heatmaps in one platform.
If you’re already on Hotjar for session recordings, their built-in survey tool is convenient and covers most use cases. The integration with session recordings — seeing the session from a user who also completed a survey — is uniquely valuable. I’ve used this combination to connect stated friction with observed behaviour.
Cost: Included in Hotjar paid plans.
Verdict: Use if you’re already on Hotjar. Use Typeform if you’re not.
Specialized Tools Worth Knowing
Lucky Orange
Best for: Small businesses wanting heatmaps + session recordings at low cost.
Lucky Orange includes dynamic heatmaps, session recordings, live visitor tracking, and form analytics at a significantly lower price point than Hotjar. The interface is less polished, but the feature set is solid for the price.
Cost: From $18/month for up to 5,000 sessions.
Verdict: Great value for small businesses. High-traffic sites will outgrow it quickly.
Crazy Egg
Best for: Scroll maps and click maps on content-heavy pages.
Crazy Egg invented the heatmap category and remains excellent at its core functionality. The scroll map reports — showing how far users scroll on each page — are useful for CRO research on landing pages and blog posts. Simple, reliable, does what it says.
Cost: From $29/month.
Verdict: Solid, but Microsoft Clarity is free and comparable for most use cases.
FullStory
Best for: Product teams and enterprise companies analyzing complex user journeys.
FullStory records every user interaction with pixel-perfect accuracy and lets you query those interactions like a database (“show me all sessions where users rage-clicked on the checkout button”). Extremely powerful for tracking down bugs and UX friction points.
Cost: Custom enterprise pricing. Not affordable for most businesses.
Verdict: Excellent for product teams. Overkill for CRO on most marketing sites.
How to Build Your CRO Stack by Budget
Under £100/month (Starting Out)
- Google Analytics 4 — Free
- Microsoft Clarity — Free
- Hotjar Observe — Free tier (limited)
- Google Forms / Typeform Free — Exit surveys
This stack gives you everything you need to do real CRO research: funnel analysis, heatmaps, session recordings, and user feedback. You won’t have proper A/B testing, but you can run sequential tests (before/after with statistical adjustment) until you can invest in proper A/B tools.
£100–500/month (Serious Testing)
- Google Analytics 4 — Free
- Microsoft Clarity or Hotjar Observe — Free–£80/month
- VWO Growth or AB Tasty — £100–300/month
- Typeform Basic — £21/month
This stack enables proper A/B testing with qualitative research to support hypothesis generation.
£500+/month (Full Program)
- Google Analytics 4 — Free
- Hotjar Business — £80/month
- VWO Growth or Enterprise — £300–600/month
- Typeform Plus — £50/month
- Looker Studio dashboards — Free
At this investment level, you have everything needed to run a full CRO program: rigorous A/B testing, deep qualitative research, and proper reporting infrastructure.
The Tool That Matters Most: None of Them
Here’s the honest truth: the CRO tool that makes the biggest difference is the one between your ears.
Every tool above is a means to an end. The end is a better understanding of your users — why they do or don’t convert, what stops them, what would help them. Tools provide data. Expertise turns that data into hypotheses, tests, and actual improvements.
A mediocre team with VWO and Hotjar will be outperformed by an expert running thoughtful tests with basic free tools. I’ve seen it happen more than once.
Invest in tools. Invest more in expertise.
Further reading:
- A/B Testing Best Practices: How to Run Tests That Mean Something — how to use these tools correctly
- CRO Audit Checklist: 37 Questions — what to look for with your new tools
- What Is Conversion Rate Optimization? — the full process these tools support
Working on your CRO stack and want a second opinion on your setup? Our CRO audit includes a full analysis of your research methodology, tool configuration, and conversion gaps. Book a free consultation →