OpenFeature SDK

Evaluate Flagship feature flags from any JavaScript runtime using OpenFeature.

OpenFeature ↗ is the CNCF standard for feature flag interfaces. It provides a vendor-neutral API so you can switch between flag providers without changing evaluation code.

The @cloudflare/flagship ↗ package is an OpenFeature-compatible SDK for evaluating Flagship feature flags. The source code is available on GitHub ↗.

The SDK includes two providers:

• FlagshipServerProvider — For server-side runtimes such as Cloudflare Workers, Node.js, and other server-side JavaScript environments. Each evaluation call makes an asynchronous request to the Flagship evaluation endpoint.
• FlagshipClientProvider — For browser applications. Pre-fetches all flag values on initialization and evaluates synchronously from an in-memory cache.

Note

If you are running inside a Cloudflare Worker, the binding is the recommended approach because it avoids HTTP overhead. You can also pass the binding to the OpenFeature SDK to get the best of both. Use the SDK without a binding when running in non-Worker runtimes like Node.js or the browser.

Installation

For server-side usage:

npm yarn pnpm bun

npm i @cloudflare/flagship @openfeature/server-sdk

yarn add @cloudflare/flagship @openfeature/server-sdk

pnpm add @cloudflare/flagship @openfeature/server-sdk

bun add @cloudflare/flagship @openfeature/server-sdk

For browser usage:

npm yarn pnpm bun

npm i @cloudflare/flagship @openfeature/web-sdk

yarn add @cloudflare/flagship @openfeature/web-sdk

pnpm add @cloudflare/flagship @openfeature/web-sdk

bun add @cloudflare/flagship @openfeature/web-sdk

Next steps

• Set up the server provider for Workers, Node.js, or other server-side runtimes.
• Set up the client provider for browser applications.