Unleash is a powerful open-source solution for feature management. It streamlines your development workflow, accelerates software delivery, and empowers teams to control how and when they roll out new features to end users. With Unleash, you can deploy code to production in smaller, more manageable releases at your own pace.

Feature flags in Unleash let you test your code with real production data, reducing the risk of negatively impacting your users' experience. It also enables your team to work on multiple features simultaneously without the need for separate feature branches.

Unleash is the most popular open-source solution for feature flagging on GitHub. It supports 15 official client and server SDKs and over 15 community SDKs. You can even create your own SDK if you wish. Unleash is compatible with any language and framework.

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This repository contains the source code for the official Unleash documentation. The site is built entirely by the Fern CLI.

API specs are committed to the repo and kept up to date by CI — you don't need to fetch them locally.

• Node.js 20+ (required to install and run the Fern CLI)
• Fern CLI: npm install -g fern-api

git clone https://github.com/Unleash/unleash-documentation.git
cd unleash-documentation
fern docs dev

That's it. The dev server starts at http://localhost:3000.

CI automatically fetches the latest OpenAPI spec from the hosted Unleash instance on every push to main and every PR. The spec is split into three domains to keep the API reference navigable:

• Admin API (fern/apis/admin-api/): All endpoints except Client and Frontend.
• Client API (fern/apis/client-api/): Client-tagged endpoints only.
• Frontend API (fern/apis/frontend-api/): Frontend API-tagged endpoints only.

You only need to run node scripts/fetch-openapi.mjs locally if you're working on API reference content and need a spec that's newer than the last CI run.

• Engine: Fern
• API specs: OpenAPI JSON files in fern/apis/, fetched by CI from a hosted Unleash instance
• Custom footer: React component (fern/components/CustomFooter.tsx), server-side rendered by Fern
• Custom styling: CSS overrides in fern/styles.css. For detailed architecture notes and conventions, see CLAUDE.md.

We welcome contributions. If you find something that's wrong, unclear, or missing, feel free to open an issue or submit a pull request.

1. Fork and clone this repository.
2. Create a new branch for your changes.
3. Run fern docs dev to preview locally.
4. Submit a pull request.

For contributions to the Unleash product itself, see the main Unleash repository.

This documentation was migrated to its own repository on 2 February 2026. It previously lived in the website folder of the main Unleash repository.

You can find the commit history prior to the migration date in the Unleash/unleash repository.