Bindings (env)

env contains only names declared on the deployment. Version Metadata is a platform-injected read-only object: id, tag, timestamp.

export default {
  async fetch(request: Request, env: Env): Promise<Response> {
    const version = env.VERSION.id;
    return env.AUTH.fetch(request);
  },
} satisfies ExportedHandler<Env>;

{
  "name": "front",
  "main": "src/index.ts",
  "services": [{ "binding": "AUTH", "service": "auth-worker" }],
  "version_metadata": { "binding": "VERSION", "tag": "release-1" }
}

Service Bindings: default/named fetch and RPC. The target must be a uniquely resolvable Worker name in the same account; deploy time freezes a target ID. entrypoint is optional.

Member signatures for KV / R2 / D1 / DO / Queue / Workflow / Assets / Images belong on those product pages. Config grammar: configuration · bindings.

Compatibility

Topic	Cloudflare	open-compute
env.BINDING types	Yes — Bindings and Service bindings	Yes
Version Metadata fields	Yes — version metadata	id, tag, timestamp
Service Bindings	Cross-region placement / global service discovery	Same-platform only; default/named fetch and RPC; target admission, deployment pins, capability lifetime, and recovery are local and fail closed
Workers for Platforms dispatcher / Dynamic Worker Loaders	Yes	Not provided
mTLS / Rate Limit / Secrets Store / AI binding	Yes	Not provided