openflagr/flagr

Health v2 · maintenance only

Adoption not part of the score

2606 stars · 204 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-30, confidence not recorded

Flagr is an open-source Go microservice for feature flagging, A/B testing, and dynamic configuration, built around a single evaluation API that returns a variant and optional JSON attachment for a given entity. It supports SQLite, MySQL, and Postgres backends, an eval-only sidecar mode fed from JSON in Git, and a web UI for managing flags.

Use cases

• decouple deployment from release with feature flags and kill switches
• run A/B tests with sticky variant assignment per user
• change runtime configuration without redeploying the app
• self-host a feature flag service with a web UI and REST API
• run an eval-only sidecar with flags defined in a Git-tracked JSON file
• roll out features gradually to targeted audience segments

When to choose

• you want a self-hosted, open-source alternative to LaunchDarkly or similar SaaS flag platforms
• you need feature flags, A/B testing, and dynamic config from one service
• you want sticky per-entity variant assignment without a per-user state store
• your stack is Go or you prefer a lightweight Docker-deployable microservice

When to avoid

• you need a mature SDK ecosystem across many languages rather than a plain HTTP API
• you require advanced experimentation analytics and statistical significance reporting
• you want a fully managed hosted solution with no operational overhead

Facets

service · maturity active

feature-flags api-framework http-server configuration-management web-development backend developer-tools apis self-hosted windows self-hosted go ab-testing dynamic-configuration kill-switch feature-toggles experimentation microservice swagger gitops linux macos docker web-server

Member repositories

For agents

markdown · JSON · MCP: product_card(name="openflagr/flagr")