Environment variables

vars are public, non-secret values. Structured-clone-compatible JSON enters env.

{
  "name": "hello-typescript",
  "main": "src/index.ts",
  "vars": {
    "GREETING": "Hello from TypeScript"
  }
}

export default {
  fetch(_request: Request, env: Env): Response {
    return new Response(env.GREETING);
  },
} satisfies ExportedHandler<Env>;

Regenerate types after changing vars:

npm

npm exec -- wrangler types

pnpm

pnpm exec wrangler types

bun

bun run wrangler types

Wrangler writes literals into worker-configuration.d.ts (for example GREETING: "Hello from TypeScript"). Bundles do not contain vars; development and deployment inject them.

Compatibility

Topic	Cloudflare	open-compute
Public strings/JSON on env, not secrets	Yes — Environment variables	Yes
Wrangler [vars] TOML	Yes	Not provided
Dashboard editor / Wrangler environments product	Yes	Not provided
Unknown top-level keys	May be ignored	Fail the whole project config
Where secrets live	Secrets product	secrets, not vars