Environment Variables & Secrets

When integrating with external services you typically store your credentials in environment variables. This is done to avoid hardcoding secrets into your codebase.

There are several environments that require different credentials, for example:

• On your local machine: Development
• Secrets on deployed Workers: Staging & Production

We follow Cloudflare’s recommended approach for workers.

Development

Create a .dev.vars file in the root of your project.

.dev.vars

SECRET_KEY = "value";
API_TOKEN = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";

This file will be used when you run the development server.

Updating Types

After you add our environment variable, run:

npx wrangler types

This adds the environment variable and associated type to worker-configuration.d.ts and avoids unknown types when accessing env.

worker-configuration.d.ts

// Generated by Wrangler by running `wrangler types`
// Runtime types generated with ....
declare namespace Cloudflare {
  interface Env {
    SECRET_KEY: string
    API_TOKEN: string
  }
}

Note: Simply running pnpm dev will not generate these runtime types.

Secrets on deployed Workers

npx wrangler secret put <KEY>

These can also be added via the Cloudflare dashboard.