Flagship Configuration

Wrangler Binding Setup

Add a Flagship binding to your Wrangler config to access flags via env.FLAGS.

Single App

// wrangler.jsonc
{
  "flagship": {
    "binding": "FLAGS",
    "app_id": "<APP_ID>"
  }
}

# wrangler.toml
[flagship]
binding = "FLAGS"
app_id = "<APP_ID>"

Multiple Apps

// wrangler.jsonc
{
  "flagship": [
    {
      "binding": "FLAGS",
      "app_id": "<APP_ID_1>"
    },
    {
      "binding": "EXPERIMENT_FLAGS",
      "app_id": "<APP_ID_2>"
    }
  ]
}

# wrangler.toml
[[flagship]]
binding = "FLAGS"
app_id = "<APP_ID_1>"

[[flagship]]
binding = "EXPERIMENT_FLAGS"
app_id = "<APP_ID_2>"

Generate Types

After adding the binding, generate TypeScript types:

npx wrangler types

This creates the Env interface with each binding typed as Flagship:

interface Env {
  FLAGS: Flagship;
  EXPERIMENT_FLAGS: Flagship; // if multiple
}

The Flagship type comes from @cloudflare/workers-types.

OpenFeature SDK Installation

Server-Side (Workers, Node.js)

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

Browser

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

SDK Provider Setup

Server Provider — With Binding (Workers)

Recommended approach inside Workers. No HTTP overhead, auth handled automatically.

import { OpenFeature } from "@openfeature/server-sdk";
import { FlagshipServerProvider } from "@cloudflare/flagship";

export default {
  async fetch(request: Request, env: Env): Promise<Response> {
    await OpenFeature.setProviderAndWait(
      new FlagshipServerProvider({ binding: env.FLAGS }),
    );
    const client = OpenFeature.getClient();
    // ... evaluate flags
  },
};

Server Provider — With App ID (Node.js)

For non-Worker runtimes. Requires an API token with Flagship read permissions.

import { OpenFeature } from "@openfeature/server-sdk";
import { FlagshipServerProvider } from "@cloudflare/flagship";

await OpenFeature.setProviderAndWait(
  new FlagshipServerProvider({
    appId: "<APP_ID>",
    accountId: "<ACCOUNT_ID>",
    authToken: "<API_TOKEN>",
  }),
);
const client = OpenFeature.getClient();

Client Provider (Browser)

Pre-fetches flags on init, then evaluates synchronously. Only prefetchFlags are available.

import { OpenFeature } from "@openfeature/web-sdk";
import { FlagshipClientProvider } from "@cloudflare/flagship";

await OpenFeature.setProviderAndWait(
  new FlagshipClientProvider({
    appId: "<APP_ID>",
    accountId: "<ACCOUNT_ID>",
    authToken: "<API_TOKEN>",
    prefetchFlags: ["promo-banner", "dark-mode", "max-uploads"],
  }),
);
await OpenFeature.setContext({ targetingKey: "user-42", plan: "enterprise" });
const client = OpenFeature.getClient();

Provider Options Reference

FlagshipServerProvider:

Provide either binding or all three of appId + accountId + authToken.

FlagshipClientProvider:

REST API Authentication

For managing flags via the REST API (create, update, delete), set these environment variables:

Base URL: https://api.cloudflare.com/client/v4/accounts/$CLOUDFLARE_ACCOUNT_ID/flagship

curl -s -H "Authorization: Bearer $CLOUDFLARE_API_TOKEN" \
  "https://api.cloudflare.com/client/v4/accounts/$CLOUDFLARE_ACCOUNT_ID/flagship/apps" | jq .

App IDs are shown in the Cloudflare dashboard under Compute > Flagship.

Local Development

Flagship bindings work in local dev with wrangler dev. Flag evaluation uses the live Flagship configuration — there is no local flag store. Ensure the app_id in your Wrangler config points to a valid app.

npx wrangler dev