Flagr vs Unleash
Flagr and Unleash are both feature flags software. Flagr is open source under Apache-2.0, with 2.6k GitHub stars. Unleash is open source under AGPL-3.0, with 14k GitHub stars.
Which to pick
- Pick Flagr when
- You want a lightweight, self-hosted flag and experiment service called over HTTP from any language.
- Pick Unleash when
- Your engineering team wants a well-established self-hosted feature flag server.
Side by side
A Go microservice for feature flags, A/B tests and dynamic configuration that returns a variant per entity through an evaluation API, with a web UI.
A feature flag platform with activation strategies, gradual rollouts, variants for experiments and SDKs for many languages, self-hosted or as Unleash's cloud.
A small community-maintained fork after Checkr stepped back.
The open-source edition lacks features such as change requests and SSO that are in paid Enterprise, and the server is AGPL-3.0.
Usable
Production-ready
Self-hosted server
Self-hosted server and cloud service
Go, Vue and PostgreSQL
TypeScript, Node.js and PostgreSQL
Open source, Apache-2.0 (permissive)
Open source, AGPL-3.0 (network copyleft)
You can build it into a product you sell, as long as you keep its copyright notice.
Use inside your business is unrestricted. If you change it and let customers use it over the internet, you must publish your changes.
2.6k GitHub stars
14k GitHub stars
Established: started 9 years ago, latest release 1.2.4.
Established: started 12 years ago, latest release v8.3.1.
Other comparisons
More feature flag platforms
Both sides were judged on 2026-11-03 from each project's README and GitHub data. License, age and popularity lines are worked out directly.