Flipt

Flipt is a self‑hosted, Git‑native feature toggle platform that treats flags as first‑class code. Every flag definition lives in a Git repository, enabling developers to version control, review, and merge changes exactly like application code. The platform exposes a RESTful API for flag evaluation, a lightweight SDK for common languages, and a real‑time Server‑Sent Events (SSE) stream that pushes flag updates to clients instantly. This design removes the need for polling and guarantees that a change in the UI or a merge to main propagates across services within milliseconds.

Architecture & Technical Stack

Flipt is written in Go and follows a micro‑service‑style monolith. The core service uses the standard library net/http and the popular chi router for request handling. Persistence is optional: by default, Flipt stores all data in a local SQLite database, but it also supports PostgreSQL and MySQL for larger deployments. The Git integration layer is built on top of go-git, allowing the service to read and write flag files directly in a Git repository. Configuration is driven entirely by environment variables, making it a true one‑binary deployment without external dependencies.

Core Capabilities

• Git‑Native Workflow – Every flag change is a commit; branches map to environments, enabling feature‑flag testing in feature branches before promotion.
• Namespaces & Environments – Flags are scoped to namespaces, which can represent teams or micro‑services. Environments (dev, staging, prod) are isolated at the namespace level, ensuring no accidental leakage.
• Evaluation API – A REST endpoint (/v1/evaluate) accepts a user context and returns the flag value. The API supports segment targeting, rollout percentages, and rule evaluation.
• SDKs & Streaming – Go, JavaScript/TS, Python, and Ruby SDKs expose a simple IsEnabled call. Each SDK can subscribe to an SSE stream (/v1/events) for real‑time updates, eliminating the 30‑second polling window common in other solutions.
• Webhooks & Extensions – Flipt can emit webhooks on flag changes, and its plugin system allows custom validation logic or integration with external services (e.g., Slack notifications).

Deployment & Infrastructure

Flipt ships as a single static binary, so no container orchestration is required. It runs natively on any Linux host and can be wrapped in Docker for CI/CD pipelines. For production, the recommended pattern is to run Flipt behind a reverse proxy (NGINX/Traefik) with TLS termination and to store the Git repository on a shared volume or network file system. Horizontal scaling is achieved by running multiple replicas behind a load balancer; the underlying database must be shared, or each replica can operate in a read‑only mode with a central PostgreSQL instance.

Integration & Extensibility

The platform’s REST API is fully documented in OpenAPI format, allowing developers to auto‑generate client libraries or integrate with existing monitoring tools. The plugin architecture exposes hooks for authentication, authorization, and rule validation, making it straightforward to plug in corporate SSO solutions or custom compliance checks. Flipt also supports environment variables for secrets, enabling integration with Vault or AWS Secrets Manager without code changes.

Developer Experience

Flipt’s documentation is concise and focuses on API usage, Git workflows, and deployment patterns. The UI is intentionally lightweight, offering a dark‑mode dashboard that mirrors the Git history of flags. Community support is active on Discord, and the project follows semantic versioning with a transparent release process. Because Flipt is open source under an Apache 2.0 license, developers can audit the codebase and contribute without vendor lock‑in.

Use Cases

1. Feature Rollouts – Deploy a new feature to staging, test with a subset of users via percentage rollouts, then merge the flag into main and promote to production.
2. Canary Releases – Use branch‑based environments to expose a flag only to a small internal group before full rollout.
3. Compliance & Security – Store sensitive feature flags in a private Git repo, ensuring that only authorized personnel can modify them.
4. A/B Testing – Define flags per namespace and use segment targeting to deliver experiments without code changes.

Advantages

• Performance – SSE delivers flag updates in milliseconds, avoiding the latency of polling.
• Flexibility – Git‑native workflow fits seamlessly into existing CI/CD pipelines; no separate feature‑flag service is required.
• Cost‑Effectiveness – Self‑hosted with a single binary; no per‑seat licensing or usage fees.
• Security & Compliance – All data remains on your infrastructure; no vendor‑managed database.

Flipt provides developers with a robust, Git‑centric feature toggle system that integrates cleanly into modern workflows while offering the scalability and security required for enterprise deployments.