Google Optimize was switched off on 30 September 2023, and with more than a million websites having used it as their free testing tool, its retirement pushed a whole generation of marketers into the wider experimentation market. Three years on, that market has matured considerably: the leading platforms now pair A/B testing with AI-driven personalisation, server-side and feature-flag testing have moved from developer niche to mainstream, and a strong group of free and open source tools has filled the gap Optimize left behind.
This updated guide covers the alternatives we recommend in 2026, from enterprise experimentation suites to tools you can run on a startup budget, and finishes with a practical way to choose between them. All of the paid platforms below integrate with Google Analytics 4 (GA4), so you can run experiments in the third-party tool and interpret results alongside your analytics data.
AB Tasty builds end-to-end experience optimisation across digital channels, letting you test your website, apps and features with a low-code and no-code approach. Its standout strength is personalisation: you can create tailored experiences for different audience segments, and its EmotionAI capability profiles visitor behaviour to inform targeting. The interface is straightforward for marketing teams, reporting is thorough, and it integrates with GA4.
AB Tasty supports A/B, multivariate, multipage, split and server-side testing, plus mobile app experimentation, and provides a library of blogs, case studies and webinars to support your optimisation programme. Pricing is by custom quote, and it is best suited to mid-market and enterprise teams with meaningful traffic.
Optimizely remains the reference point for enterprise experimentation. It allows you to run omnichannel experiments, generate insights and continually optimise experiences across web, mobile apps, email and other digital touchpoints, and its marketer-friendly visual editor means many tests need no developer time. In recent years Optimizely has folded its experimentation tools into a wider digital experience platform with AI assistance (branded Opal) threaded through content, testing and personalisation workflows.
It covers A/B, multipage, multivariate, server-side and app testing, backed by a mature stats engine. Its optimisation glossary is still one of the best free references in the industry. Pricing is quote-based depending on the products you need; this is an enterprise-grade investment.
VWO is arguably the most natural home for former Google Optimize users: it offers a genuinely useful free starter plan for web testing, an intuitive visual editor, and a smooth upgrade path as your programme scales. Beyond A/B, multivariate, multipage, split, server-side and mobile app testing, VWO bundles behaviour analytics (heatmaps, session recordings, funnels and surveys) into the same platform, which makes it strong value for teams that want research and testing in one place.
Pricing differs by product and scales with monthly tracked users, with the free web testing tier a sensible starting point for smaller sites.
Kameleoon has grown into one of the strongest European experimentation platforms, popular with e-commerce, media and financial services teams. It combines web experimentation, feature experimentation and AI-driven personalisation in a single platform, with an AI copilot that helps non-technical users build and analyse tests. It is also notable for strict European data residency and privacy compliance, which matters if your legal team scrutinises where experiment data lives. Pricing is by custom quote.
GrowthBook is an open source experimentation platform built around feature flags and warehouse-native analysis: rather than collecting its own analytics, it reads experiment results directly from your existing data warehouse or GA4 data. That makes it a favourite of product and engineering teams who want full control of their data and statistics. You can self-host it free of charge, and the hosted cloud version has a free tier with paid plans as you scale. The trade-off is that it is developer-led: there is no visual editor aimed at marketers, so it suits teams with engineering support.
PostHog bundles product analytics, session replay, feature flags and A/B testing into one open source platform with generous usage-based free allowances. For startups and product-led teams it is often the most cost-effective way to get experimentation running, because the analytics you need to interpret results live in the same tool. Like GrowthBook, it is aimed more at product and engineering workflows than at marketers wanting a point-and-click editor.
In a rapidly evolving digital landscape, staying competitive requires continuous adaptation. Experimentation is the discipline that stops website changes being a matter of opinion: with a deeper understanding of your audience's preferences and behaviour, you can tailor experiences to their needs, and systematic A/B testing and personalisation feed directly through to conversion rate, sales, sign-ups and other valuable actions. It also protects you from expensive mistakes, since a losing variation quietly retired in a test is far cheaper than a losing redesign rolled out to everyone.
Start from your team's shape rather than from feature lists. If marketers will run the programme with limited developer time, prioritise a visual editor and ease of use: VWO, AB Tasty, Kameleoon and Optimizely all fit. If your experimentation is product-led and engineering-driven, the open source, feature-flag-first tools GrowthBook and PostHog will fit your workflow better and cost dramatically less. Then weigh traffic volume (statistical power decides how many tests you can realistically run), integration with GA4 and your data stack, privacy and data residency requirements, the role you want AI to play in generating and analysing tests, and total cost as your tracked-user numbers grow. Most paid platforms offer trials or free tiers, so shortlist two, run the same simple test in both, and let your team's experience decide.
A testing tool is only as good as the hypotheses you feed it. Target Internet's e-learning platform includes structured courses on conversion rate optimisation, analytics and data-driven decision making, with skills benchmarking to show you exactly where your team needs to develop. Explore our membership options and build an experimentation capability, not just a tool subscription.
Google's announcement of the Optimize sunset: support.google.com/optimize. Tool documentation and pricing: AB Tasty, Optimizely, VWO, Kameleoon, GrowthBook and PostHog.
In this episode Ciaran speaks to Pacey AI, about avoiding AI slop and getting back to the work that matters: understanding customers, developing ideas and building a distinctive brand.