OpenFeature SDK

Evaluate Flagship feature flags 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.

Flagship provides official OpenFeature-compatible SDKs for TypeScript, Python, and Go. The source code is available on GitHub ↗.

SDK	Package	Runtime	Evaluation modes
TypeScript	`@cloudflare/flagship` ↗	Workers, Node.js, browsers	Workers binding, HTTP, browser prefetch cache
Python	`cloudflare-flagship` ↗	Python server applications	HTTP
Go	`github.com/cloudflare/flagship/sdks/go` ↗	Go server applications	HTTP

SDKs

Flagship SDKs are organized by language. The TypeScript SDK has separate setup guides for server-side and browser usage because they use different OpenFeature packages and runtime behavior.

TypeScript Server SDK — For Workers, Node.js, and other server-side JavaScript runtimes.
TypeScript Client SDK — For browser applications that need synchronous OpenFeature web SDK evaluation.
Python SDK — For Python server applications.
Go SDK — For Go server applications.

Installation

For TypeScript server-side usage:

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

For TypeScript browser usage:

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

For Python:

uv add cloudflare-flagship

For Go:

go get github.com/cloudflare/flagship/sdks/go

Next steps

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