Gateway Workers

Read the current Forward guide before implementing a Worker. It defines how Gateway invokes Workers on permitted HTTP traffic. Retrieve the relevant page below rather than copying setup, API payloads, or limits into the project from memory.

Workflow

1. Inspect the existing Worker and choose a Worker template for the required transformation, synthetic response, or background task.
2. Export a named GatewayMiddleware class extending WorkerEntrypoint from cloudflare:workers. Implement handle(request, context, next) and return a Response. Gateway calls this method through RPC. A default fetch() handler alone does not implement the Forward contract.
3. For TypeScript, follow the chosen template's current package installation and type-import instructions.
4. Use the second argument for Gateway context. It describes the original request and stays unchanged when the Worker modifies the request. Keep it distinct from this.ctx (Workers execution context) and this.env (bindings).
5. Continue the user's request with next(request) at most once, or return a synthetic response without calling it. next() always targets the original destination. Changes to the destination URL or host are ignored, and it cannot redirect, retry, or fan out. Use fetch() to send a request to a different destination. It creates an independent subrequest that does not inherit the user's Gateway policies or egress configuration.

Context

Use the published types and context reference for field names and availability. Treat a falsy identity (!identity) as anonymous and guard optional posture values. Call await context.identity() or await context.devicePosture() only when needed. Both getters can reject. Catch lookup failures separately from missing values and decide how to handle each when the Worker depends on them. Use Gateway-provided identity rather than client-supplied identity headers.

Gateway behavior

• Only the first matching Forward policy invokes a Worker. Worker invocation does not confirm successful body inspection. Follow the Forward guide's inspection order.
• Gateway inspects the final response, including synthetic responses. Modified request bytes are not inspected again before reaching the origin.
• Review the Forward guide's limitations before choosing traffic: HTTPS requires decryption, WebSockets bypass the Worker, and matching Workers VPC traffic is dropped. Worker invocation failures fail closed.

Validation

Type-check against the installed Gateway types and test the named RPC entrypoint, including zero or one continuation call and the context values the Worker uses. Then test a permitted request through a scoped Gateway Forward policy. A direct request to a default fetch() handler does not validate the Gateway path. Follow the chosen template's test procedure and the Forward guide's troubleshooting steps.

Check the response and streaming rules: return a final status from 200 to 599, return no body for HEAD requests or statuses 204, 205, and 304, and stream bodies rather than buffering them.

Related skills

• cloudflare-one: Gateway policy design, traffic paths, identity, TLS, and rollout.
• workers-best-practices: streaming, bindings, generated environment types, background work, observability, and runtime tests.
• CLI selection: choose the existing cf-cli or wrangler skill for project setup and deployment.