--- title: Get started description: Create your first Flagship feature flag and evaluate it inside a Cloudflare Worker using the binding API. image: https://developers.cloudflare.com/dev-products-preview.png --- > Documentation Index > Fetch the complete documentation index at: https://developers.cloudflare.com/flagship/llms.txt > Use this file to discover all available pages before exploring further. [Skip to content](#%5Ftop) # Get started In this guide, you will create a feature flag in Flagship and evaluate it inside a Cloudflare Worker. ## Create an app and a flag In this example, you will create a boolean flag called `new-checkout` that controls whether users see a new checkout experience. 1. Log in to the [Cloudflare dashboard ↗](https://dash.cloudflare.com/) and select your account. 2. Go to **Compute** \> **Flagship**. 3. Select **Create app**. Give the app a name that matches your project or service (for example, `checkout-service`). 4. Inside the app, select **Create flag**. 5. Create a boolean flag with the key `new-checkout`. Optionally, add [targeting rules](https://developers.cloudflare.com/flagship/targeting/) to control who sees the flag. 6. Turn on the flag and select **Save**. ## Add the Flagship binding to your Worker Add the Flagship binding in your Wrangler configuration file so your Worker can evaluate flags through a binding. * [ wrangler.jsonc ](#tab-panel-8890) * [ wrangler.toml ](#tab-panel-8891) JSONC ``` { "flagship": [ { "binding": "FLAGS", "app_id": "", }, ],} ``` TOML ``` [[flagship]]binding = "FLAGS"app_id = "" ``` Replace `` with the app ID shown in the [Cloudflare dashboard ↗](https://dash.cloudflare.com/?to=/:account/flagship). The `binding` field sets the name you use to access Flagship in your Worker code. In this example, the binding is available as `env.FLAGS`. After updating the Wrangler configuration, run `npx wrangler types` to generate TypeScript types for the binding. ## Evaluate the flag in your Worker Use the `env.FLAGS` binding to evaluate the flag. The binding provides type-safe methods that return the flag value and fall back to the default you provide if evaluation fails. * [ JavaScript ](#tab-panel-8892) * [ TypeScript ](#tab-panel-8893) JavaScript ``` export default { async fetch(request, env) { const url = new URL(request.url); const userId = url.searchParams.get("userId") ?? "anonymous"; const showNewCheckout = await env.FLAGS.getBooleanValue( "new-checkout", false, { userId }, ); if (showNewCheckout) { return new Response("Welcome to the new checkout experience!"); } return new Response("Standard checkout."); },}; ``` TypeScript ``` export default { async fetch(request: Request, env: Env): Promise { const url = new URL(request.url); const userId = url.searchParams.get("userId") ?? "anonymous"; const showNewCheckout = await env.FLAGS.getBooleanValue( "new-checkout", false, { userId }, ); if (showNewCheckout) { return new Response("Welcome to the new checkout experience!"); } return new Response("Standard checkout."); },}; ``` The third argument to `getBooleanValue` is the [evaluation context](https://developers.cloudflare.com/flagship/concepts/#evaluation-context). Flagship uses the context attributes to match targeting rules. In this example, the `userId` attribute is passed so that percentage rollouts and user-specific targeting work correctly. ## Deploy and test Deploy your Worker: Terminal window ``` npx wrangler deploy ``` Test flag evaluation by sending a request: Terminal window ``` curl "https://..workers.dev/?userId=user-42" ``` Change the flag value or targeting rules in the dashboard and observe the updated response. Flag changes propagate globally within seconds. ## (Optional) Use the OpenFeature SDK If you prefer the [OpenFeature ↗](https://openfeature.dev/) standard interface, or if you are running outside of a Cloudflare Worker, you can use the [@cloudflare/flagship ↗](https://www.npmjs.com/package/@cloudflare/flagship) SDK instead of the binding. Install the SDK: 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 ``` Evaluate flags using the OpenFeature client: * [ With binding ](#tab-panel-8898) * [ With app ID ](#tab-panel-8899) Pass the Flagship binding directly to the provider. This avoids additional HTTP overhead and is the recommended approach inside a Worker. The binding handles authentication automatically. * [ JavaScript ](#tab-panel-8896) * [ TypeScript ](#tab-panel-8897) JavaScript ``` import { OpenFeature } from "@openfeature/server-sdk";import { FlagshipServerProvider } from "@cloudflare/flagship/server"; export default { async fetch(request, env) { await OpenFeature.setProviderAndWait( new FlagshipServerProvider({ binding: env.FLAGS }), ); const client = OpenFeature.getClient(); const showNewCheckout = await client.getBooleanValue( "new-checkout", false, { targetingKey: "user-42" }, ); return new Response( showNewCheckout ? "New checkout!" : "Standard checkout.", ); },}; ``` TypeScript ``` import { OpenFeature } from "@openfeature/server-sdk";import { FlagshipServerProvider } from "@cloudflare/flagship/server"; export default { async fetch(request: Request, env: Env): Promise { await OpenFeature.setProviderAndWait( new FlagshipServerProvider({ binding: env.FLAGS }), ); const client = OpenFeature.getClient(); const showNewCheckout = await client.getBooleanValue( "new-checkout", false, { targetingKey: "user-42" }, ); return new Response( showNewCheckout ? "New checkout!" : "Standard checkout.", ); },}; ``` Use an app ID, account ID, and an API token when running outside of a Worker (for example, in Node.js). Generate an [API token](https://developers.cloudflare.com/fundamentals/api/get-started/create-token/) from your Cloudflare account with Flagship Evaluate permission. * [ JavaScript ](#tab-panel-8894) * [ TypeScript ](#tab-panel-8895) JavaScript ``` import { OpenFeature } from "@openfeature/server-sdk";import { FlagshipServerProvider } from "@cloudflare/flagship/server"; await OpenFeature.setProviderAndWait( new FlagshipServerProvider({ appId: "", accountId: "", authToken: "", }),); const client = OpenFeature.getClient(); const showNewCheckout = await client.getBooleanValue("new-checkout", false, { targetingKey: "user-42",}); ``` TypeScript ``` import { OpenFeature } from "@openfeature/server-sdk";import { FlagshipServerProvider } from "@cloudflare/flagship/server"; await OpenFeature.setProviderAndWait( new FlagshipServerProvider({ appId: "", accountId: "", authToken: "", }),); const client = OpenFeature.getClient(); const showNewCheckout = await client.getBooleanValue("new-checkout", false, { targetingKey: "user-42",}); ``` Refer to the [SDK documentation](https://developers.cloudflare.com/flagship/sdk/) for detailed setup instructions. ## Next steps * Learn about [targeting rules](https://developers.cloudflare.com/flagship/targeting/) to serve different values based on user attributes. * Explore the full [binding API reference](https://developers.cloudflare.com/flagship/binding/) for all evaluation methods. * Read about [percentage rollouts](https://developers.cloudflare.com/flagship/targeting/percentage-rollouts/) for gradual feature releases. * Refer to the [Flagship API reference](https://developers.cloudflare.com/flagship/reference/api-reference/) to manage Flagship programmatically. ```json {"@context":"https://schema.org","@type":"TechArticle","@id":"https://developers.cloudflare.com/flagship/get-started/#page","headline":"Get started · Cloudflare Flagship docs","description":"Create your first Flagship feature flag and evaluate it inside a Cloudflare Worker using the binding API.","url":"https://developers.cloudflare.com/flagship/get-started/","inLanguage":"en","image":"https://developers.cloudflare.com/dev-products-preview.png","dateModified":"2026-06-24","publisher":{"@type":"Organization","name":"Cloudflare","url":"https://www.cloudflare.com/"},"isPartOf":{"@type":"WebSite","@id":"https://developers.cloudflare.com/#website","name":"Cloudflare Docs","url":"https://developers.cloudflare.com/"}} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/directory/","name":"Directory"}},{"@type":"ListItem","position":2,"item":{"@id":"/flagship/","name":"Flagship"}},{"@type":"ListItem","position":3,"item":{"@id":"/flagship/get-started/","name":"Get started"}}]} ```