Experimentation & feature flags · Optimizely

Optimizely

One of the original A/B testing platforms, now the experimentation module of a broader digital-experience suite (CMS, commerce, personalization).

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Optimizely's experimentation product supports A/B, multi-page, feature-flag, and server-side testing, and remains the part of the company most analysts associate with the brand. Its Stats Engine, developed with Stanford researchers, uses a mixture Sequential Probability Ratio Test (mSPRT) to produce "always-valid" p-values, so results stay statistically sound even when checked repeatedly ("peeking") rather than only at a pre-computed sample size. Beyond experimentation, Optimizely now sells a much wider Agentic Experience suite — CMS, content marketing, commerce, asset management, a data platform, and feature management — sold as individually packaged bundles, so a buyer evaluating "Optimizely" today is often choosing among a multi-product platform rather than a standalone testing tool. Deployment is cloud-hosted, targeting product, growth, and marketing teams running structured experimentation programs.

At a glance

Vendor Optimizely
Pricing model Quote only
Free tier —
Deployment Cloud
Open source No
Best for Teams wanting mature statistical rigor for web/feature experiments, especially if also evaluating Optimizely's CMS or commerce products.

Pricing

Individually packaged custom quote; no public pricing figures.

Checked on the vendor's own page on September 21, 2026: no prices are published. Expect to be quoted.

Features

  • A/B, multivariate, and multi-page web testing
  • Feature-flag and server-side experimentation
  • Stats Engine: sequential testing via mixture SPRT for always-valid results
  • Real-time audience targeting and personalization
  • Warehouse-native analytics option
  • Part of a broader CMS/commerce/personalization suite

Integrations

Profile last reviewed September 21, 2026

Head to head

Alternatives

VWO Long-running web experimentation and personalization platform, using a Bayesian stats engine, now merging with AB Tasty under the Wingify brand. AB Tasty French web experimentation and personalization platform defaulting to Bayesian reporting, now merged with VWO under the Wingify brand. Kameleoon Web experimentation and feature-management platform supporting frequentist, sequential, and Bayesian analysis side by side.

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Terms to know

A/B testing A controlled experiment that compares two variants to measure which one produces a better outcome. Statistical significance A threshold judgment that an observed effect is unlikely to be due to chance alone, given the data and test used. P-value The probability of observing data at least as extreme as the result, if the null hypothesis were actually true. Sample size The number of observations in a study or test, which determines how precisely and reliably an effect can be measured. Sequential testing An analysis method that lets experiments be checked continuously without inflating the false-positive rate from repeated peeking.

Related guides

How to choose an experimentation and feature-flag platform Pick by where your experiment data comes from — flag telemetry or your own warehouse — and which statistical engine your team trusts, not feature count. How to set up an experimentation program From your first A/B test to a durable program — the plumbing, the statistics rules, the review ritual, and the tools that support each stage.