The Best A/B Testing Tools for SaaS in 2026 (Compared)

Google Optimize shut down in 2023, and since then SaaS teams have had to choose a paid or open-source replacement. The choice is harder than it looks, because "A/B testing" now covers two different jobs: changing a landing page in a visual editor, and rolling out a product change to half your users behind a feature flag.

We compared the experimentation tools SaaS teams use most, by the kind of testing each does best. Pricing is usually based on traffic or tracked users and changes often, so check each vendor's current plans.

Website testing vs product testing

Website testing covers your marketing site: headlines, pricing page layouts, sign-up forms and calls to action. Marketers want a visual editor and fast set-up. Product testing covers your app: onboarding flows, feature changes and paywalls. Engineers want feature flags, SDKs and results tied to product metrics such as activation and retention. Know which job you are hiring the tool for.

What to look for

• Testing type: client-side visual editor, server-side and feature flags, or both.
• Statistics: a sound, transparent stats engine (frequentist, Bayesian or sequential) that protects you from calling tests too early.
• Metrics: can you measure beyond clicks, such as sign-ups, activation, trial-to-paid and revenue?
• Performance: does the script cause page flicker or slow your site?
• Data connection: can it read metrics from your product analytics or data warehouse?

Quick comparison

Tool	Best for	Strength
Optimizely	Enterprise experimentation programmes	Web and feature experimentation at scale
Wingify (VWO + AB Tasty)	Marketing and CRO teams	Visual testing plus behaviour insights
Statsig	Product and engineering teams	Feature flags with strong statistics
PostHog	Startups and engineering-led teams	Experiments built into product analytics
GrowthBook	Teams with a data warehouse	Open source and warehouse-native
Convert	Privacy-conscious CRO teams and agencies	Flicker-free testing and privacy focus
LaunchDarkly	Engineering teams shipping safely	Feature management with experimentation

1. Optimizely

Best for: larger SaaS companies running a formal experimentation programme.

Optimizely covers both web experimentation and feature experimentation, so marketing and product teams can test on the same platform. Its stats engine, targeting and governance features are built for teams running many tests at once. It is priced for the enterprise, so it makes most sense once experimentation is a core, staffed function.

2. Wingify (VWO and AB Tasty)

Best for: marketing and CRO teams testing landing pages, pricing pages and sign-up flows.

VWO and AB Tasty, two of the best-known CRO platforms, merged in 2026 and now operate under the Wingify brand. Both are known for visual editors that let marketers launch tests without engineering, plus heatmaps, session recordings and surveys to find out what to test in the first place. Existing VWO and AB Tasty customers continue to be served as the platforms come together. For SaaS teams focused on website conversion, this is one of the strongest options.

3. Statsig

Best for: product and engineering teams testing inside the app.

Statsig combines feature flags, experimentation and product analytics, with a statistics engine respected by data teams. OpenAI acquired Statsig in 2025, and the company said Statsig would continue to operate and serve its existing customers. It suits SaaS teams that want every product release to be measurable.

4. PostHog

Best for: startups that want experiments in the same tool as their analytics.

PostHog's experiments sit alongside its product analytics, feature flags and session replay, so you can launch a test and analyse its effect on activation or retention without moving data between tools. It has a generous free tier and usage-based pricing, which makes it an easy place to start testing in the product.

5. GrowthBook

Best for: teams with a data warehouse that want control and transparency.

GrowthBook is open source and warehouse-native: it reads metrics directly from Snowflake, BigQuery and similar warehouses, so your experiment results use the same data as the rest of your reporting. You can self-host it or use the cloud version. It suits data-mature SaaS teams that do not want their metrics locked inside a vendor.

6. Convert

Best for: CRO teams and agencies that care about speed and privacy.

Convert Experiences focuses on flicker-free website testing and a privacy-first approach, and it is popular with CRO specialists for its flexibility and support. It is a solid choice for testing marketing pages without enterprise pricing.

7. LaunchDarkly

Best for: engineering teams that want safe releases and the option to experiment.

LaunchDarkly is best known for feature flags: releasing to a small group first, rolling back instantly and targeting features by plan or account. It has added experimentation on top, so a team already using it for releases can test the impact of those releases without another tool.

How to choose

1. Testing your website and pricing page? Start with Wingify or Convert; consider Optimizely at enterprise scale.
2. Testing inside the product? Look at Statsig, PostHog or LaunchDarkly.
3. Data team with a warehouse? GrowthBook keeps results consistent with your other reporting.
4. Early-stage with little traffic? Use PostHog's free tier, and test bold changes rather than button colours.

A tool will not tell you what to test. The best test ideas come from research: analytics, session recordings and conversations with users. If you are not sure where to start, our list of 9 pricing page tests worth running is a good first backlog.

FAQ

What replaced Google Optimize?

There is no single official replacement. Most SaaS teams moved to a dedicated tool such as Wingify (VWO and AB Tasty), Optimizely, Convert or PostHog, depending on budget and whether they test the website or the product.

How much traffic do we need to A/B test?

It depends on your conversion rate and the size of change you want to detect, but low-traffic B2B sites often need weeks to reach a reliable result. Test larger changes, test fewer things at once and use a sample size calculator before you start.

Should marketing and product use the same testing tool?

Ideally they share metrics, even if they use different tools. Optimizely and PostHog can cover both jobs; many teams use a visual tool for the website and a feature-flag tool for the product.

Want a testing programme that lifts sign-ups and trial-to-paid conversion? See our CRO for SaaS service.

Tool details were gathered from vendor information and public reviews at the time of writing and change frequently. Rapid North has no commercial relationship with the vendors listed.