Best Open-source Feature Flags tools

GrowthBook

Open Source Feature Flagging and A/B Testing Platform

FeatureHub

Cloud Native feature flags, A/B testing, and remote configuration platform

GO Feature Flag

Lightweight, multi-language feature flag service with relay proxy

Flipt

Git-native feature management platform for modern development teams

Flagsmith

Open-Source Feature Flagging and Remote Config Platform

Featurevisor

Git-based feature flags and experimentation for developers

Unleash

Feature flag platform enabling safe, incremental releases

FeatBit

Self-hosted feature flag platform for safe deployments

Bucketeer

Feature flag management and A/B testing platform

Togglz

Dynamic runtime feature toggles for Java applications

Flagger

Progressive delivery automation for Kubernetes with canary deployments

Flagr

Deliver targeted experiences with feature flags and A/B testing

Flipper

Beautiful, performant feature flags for Ruby and Rails

Split

Rack‑based A/B testing framework for Rails, Sinatra, and more

Rollout

Redis-backed feature flags for Ruby with granular rollout control

FeatureProbe

Open source feature management for confident, low-risk deployments