Growthbook Release Notes

GrowthBook 5.1 includes over 400 commits touching almost every part of the product. Below are some of the highlights.

Highlights

Contextual Bandits (beta) - One size doesn’t fit all. Contextual Bandits let you run personalization experiments to find the best performing variant for each group of users. The bandit continuously learns and updates weights as it runs and helps you pick out the signal from the noise.

Saved Learnings - Document deeper learnings about your users that you’ve discovered through experimentation. Let our agent automatically scan your past tests to get you started or use our new API endpoints and agent skills to build your own workflows around this invaluable data.

Funnel Metrics - Easily measure funnel completion in your experiments and see where users are dropping off. Perfect for testing marketing funnels, onboarding flows, and anything else where users progress through a series of steps.

Hosted MCP + OAuth - Users on GrowthBook Cloud can now connect to our hosted MCP server at mcp.growthbook.io and incorporate our 30+ agent skills into your workflows. Pull GrowthBook experiment results into Notion, create feature flags from Jira tickets, query product analytics data from Claude Desktop, and so much more. …

Security Patch Release

• Fixes critical auth vulnerability affecting self-hosted non-SSO deployments with publicly accessible /auth/* endpoints
• Switches to Docker Hardened base images to reduce exposure to 3rd party vulnerabilities
• Bump dependency versions to address various security vulnerabilities
• New Databricks OAuth M2M option for increased security
• New org setting to completely disable all Personal Access Tokens
• Various performance and bug fixes throughout the app

We recommend all self-hosted users update as soon as possible.

This is also a great time to read through our production hardening docs and ensure you are following all best practices for security.

Despite the major version bump, GrowthBook 5.0 does not have any breaking changes and can be upgraded to safely.

A year ago when we released version 4.0, the world of product development looked completely different. Claude Code had just launched, agent skills didn't exist yet, engineers were still writing code by hand. The world today is almost unrecognizable. GrowthBook too has changed rapidly in that time and we wanted to signify the massive improvements over the past year with a new major version.

Agentic Experience

Everything a human can do in the GrowthBook UI, an Agent should be able to do programatically. We aren’t 100% there yet, but this release pushes us much closer to that goal:

• Official Skills for common workflows like starting an experiment, summarizing results, or cleaning up stale flags. Use these in Claude, Cursor, Codex, or wherever else your agents live.
• In-App Assistant with access to the same set of Official Skills, plus context about what page you are currently viewing. Use this to quickly automate tasks in the UI or ask questions about your flags or experiments without leaving GrowthBook.
• GrowthBook CLI - Brand new, with 100% coverage of our public REST API endpoints and a much better agent (and developer) experience.

Feature Flag Governance …