Unleash Documentation

What is Unleash?

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.

Try Unleash Enterprise for free

About this repository

This repository contains the source code for the official Unleash documentation, powered by Fern.

Quickstart

Prerequisites

• Node.js 20+

To get the documentation environment running locally, follow these steps:

Clone the repository

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

Install dependencies

npm install

Install the Fern CLI

npm install -g fern-api

Start the development server

npm run dev

Once the server starts, you can view the documentation at http://localhost:3000.

Command reference

Command	Action
npm run dev	Fetches latest specs and starts the dev server.
fern docs dev	Starts the dev server directly (does not fetch specs).
npm run fetch	Updates the local openapi.json files from the hosted instance.
fern check --strict-broken-links	Validates the documentation and fails on broken links.

Architecture and tooling

Our docs stack has the following components:

• Engine: Fern.
• API specs: OpenAPI spec fetched dynamically from the Unleash instance.
• Custom footer: A React component (fern/components/CustomFooter.tsx) server-side rendered by Fern via the footer: property in docs.yml.
• Custom styling: CSS overrides in fern/styles.css.

API structure

To keep our API reference navigable, we split the main Unleash OpenAPI spec into three distinct domains:

• Client API (fern/apis/client-api/): Contains only endpoints with the "Client" tag.
• Frontend API (fern/apis/frontend-api/): Contains only endpoints with the "Frontend API" tag.
• Admin API (fern/apis/admin-api/): Contains all remaining endpoints (excludes Client and Frontend API tags).

Custom styling

We apply custom CSS on top of Fern's defaults to achieve our branded look (floating content containers, mountain backdrop, custom navbar styling, academy section, footer). The main stylesheet is fern/styles.css.

Key design elements:

• Floating container: Guide and reference pages render inside a white rounded card over a gray background.
• Mountain backdrop: A decorative mountain texture fixed to the bottom-right corner via body::after, layered behind content with z-index management.
• Custom footer: A React component at fern/components/CustomFooter.tsx, server-side rendered by Fern. Styled via CSS classes in styles.css.

For detailed architecture notes, gotchas, and instructions for working on the CSS, see CLAUDE.md.

Contributing

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

To contribute:

1. Fork and clone this repository.
2. Create a new branch for your changes.
3. Run the dev server locally to preview your changes using npm run dev.
4. Submit a pull request to this repository.

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

Migration history

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.