GrowthBook Version 3.0

New Edge SDKs, CUPED for Bayesian, Custom Roles, OpenFeature Support and more!

· 4 min read
Hero image listing a summary of features in GrowthBook version 3

We’re super excited to announce the release of GrowthBook 3.0! This is a huge release and includes brand new Edge SDKs (Cloudflare, Fastly, and Lambda), support for custom priors and CUPED in our Bayesian stats engine, and a lot more! Full details below.

A/B Testing on the Edge

We’re proud to announce dedicated SDKs for Cloudflare Workers, Lambda@Edge, and Fastly Compute! These new integrations allow you to easily run A/B tests on your website with zero compromises. Combine the crazy fast load times and reliability of a CDN with the power and flexibility of client-side A/B testing, all with zero flickering and a dead simple setup.

How does it work? Our Edge SDKs sit in front of your website and modify the HTML before it reaches your users. No blocking script tags, no flickering, no adblock issues, and no need to write any custom code.

Our Edge SDKs support Visual Editor experiments, URL Redirect tests, and Feature Flags.  Check out the docs for Cloudflare, Fastly, Lambda, and other Edge platforms.

Bayesian Priors and CUPED Support

For this 3.0 release, we completely overhauled our Bayesian stats engine, which resulted in some exciting new features and general accuracy and reliability improvements.

You can now configure informative priors on a per-metric and organization-wide basis. Instead of starting each test from zero, we can start with some prior beliefs - for example, the knowledge that most of your experiments only change revenue by at most +-5%. Picking good priors can help reduce your false positive rate and give you more confidence in your results.

CUPED is a powerful technique that analyzes user behavior in the weeks before an experiment to cancel out variance during the test. In some cases, this can cut the required running time in half! We’ve supported CUPED since version 2.0 in our Frequentist engine, and now in version 3.0, we’re excited to bring support to Bayesian.

Read more about these updates on our blog.

Custom Roles

Our long-awaited Enterprise feature - Custom Roles - is finally live!  Want an `engineer` role but without the ability to modify saved groups? Or an `admin` who can do everything except invite new team members? Both of these are now possible, along with whatever other crazy combos you can come up with. We’re starting with a “small” list of 35 permission policies to mix and match from, but we plan to add more fine-grained options in the future, so let us know what you’d like to see!

View the Custom Role docs for more details.

OpenFeature Support

We’re excited to join the OpenFeature ecosystem with an official GrowthBook Provider.  This initial release adds support for the Web and React SDKs, but we plan to add providers for all supported languages soon, so stay tuned!

Experiment Slack/Discord Alerts

We have big plans for alerting and webhooks and to kick us off, we’re launching a new `experiment.warning` event that is triggered when there’s a Sample Ratio Mismatch (SRM) error, results fail to update, or if we detect Multiple Exposures (users seeing multiple variations).

As with all of our events and webhooks, you can filter these alerts by project, environment and tag and route them to Slack, Discord, or any other custom destination.

Stay tuned for many more events and updates coming soon!

JSON Feature Flag Editor

Way back in version 2.2, we added Enterprise JSON Schema validation for feature flags. This was great for avoiding typos and ensuring consistency in your JSON feature values. However, there were two big drawbacks. First, you had to write JSON Schema from scratch, which can be very tedious and time-consuming. Second, users still had to type raw JSON when setting the feature value, which is not the most user-friendly.

In this release, we set out to solve both of these problems. There’s a brand new “Simple” validation option with an easy-to-use schema builder - no need to write JSON Schema from scratch. More excitingly, we now use this schema to generate a user-friendly UI throughout GrowthBook! With these changes, you now get JSON validation and a better UX, all without needing to write any code.

New Next.js Examples

We’ve updated our Next.js examples to include all the new rendering strategies available with the Next 14 App Router.  We show how to use GrowthBook inside of React Server Components, how to integrate with the built-in fetch cache (with webhook revalidation), plus a powerful hybrid strategy that lets you do client-side feature flagging without any client-side network requests!

Check out the new App Router examples, along with our updated Pages Router examples.

SDK Updates

The GrowthBook team and community have worked hard to create and improve our SDKs. We’ve added a new React Native SDK, completely refreshed the Elixir, GoLang, and C# SDKs, and improved the Java, Python, Ruby, JS, React, Flutter, Swift, and Kotlin SDKs.

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