Go Feature Flag

GO Feature Flag is a feature flag system for teams that want rollouts and targeting without running a database or paying per seat. Flags live in a file you already control, and a single relay proxy on your infrastructure serves them to your apps. It's MIT licensed.

Apps read flags through OpenFeature SDKs, so you aren't tied to one vendor's client library. Changing a percentage, a targeting rule or adding a flag needs no redeploy.

• Rollout controls: targeting rules, canary releases, progressive rollouts over a time frame, and scheduled changes.
• A/B testing: split audiences into groups and export who saw which variation.
• Retrievers: load configuration from S3, Google Cloud Storage, Azure Blob Storage, GitHub, GitLab, Kubernetes ConfigMaps, HTTP and more.
• Exporters: send flag usage data to places like BigQuery, Kafka, Kinesis, Redis, PostgreSQL, MongoDB or OpenTelemetry.
• Notifiers: get alerted in Slack, Discord, Microsoft Teams or through a webhook when a flag changes.
• Language support: providers cover JavaScript, TypeScript, React, Angular, Swift, Kotlin, Go, Java, .NET, Python, PHP, Ruby, Rust and NestJS.

It suits engineering teams that want to separate deploy from release, test in production with a limited audience, and switch a feature off fast when a bug appears. Non-developers can adjust rollouts too, since changes happen in configuration rather than code.

Compared with SaaS platforms, it runs entirely in your own infrastructure. Compared with database-backed open source tools like Unleash or Flagsmith, it needs no database at all. You can also browse other feature flag tools to compare approaches.