GrowthBook vs Optimizely

Side-by-side from the Top 11 ranking of The 11 Best A/B Testing Tools (2026). Last verified June 13, 2026.

The short answer

Optimizely ranks higher on Top 11 (#1 vs #11) for Growth teams running experiments. The enterprise standard for its powerful stats engine and full-stack experimentation features.

At a glance

GrowthBookOptimizely
Top 11 rank#11 / The 11 Best A/B Testing Tools (2026)#1 / The 11 Best A/B Testing Tools (2026)
Score (out of 9.4)7.49.2
Best forOpen-source testing on your data warehouseEnterprise-scale experimentation
Pricing$ (Free to custom)$$$$$ (Custom enterprise plans)
HQSan Francisco, USANew York, USA
Founded20202009

GrowthBook

An open-source tool that runs on your data warehouse, giving you full data ownership.

www.growthbook.io

See full entry in The 11 Best A/B Testing Tools (2026)

Optimizely

The enterprise standard for its powerful stats engine and full-stack experimentation features.

www.optimizely.com

See full entry in The 11 Best A/B Testing Tools (2026)

Methodology and scoring weights live at /methodology. No vendor pays for placement — see about.