# Service Execution

Choose the right integration type based on whether you need a local module import or a bound Worker method call. The `service` type bundles handler code with the gateway worker, while `service_binding` calls a separately deployed Worker. This page compares both patterns to help you pick the right one for your use case.

**Last reviewed:** 2026-03-06

## When to use this

Use the service execution recipes when your routes need to call Worker code directly instead of proxying to an external HTTP endpoint. The gateway supports two patterns: local service modules bundled with the worker, and service bindings that call separately deployed Workers via Cloudflare bindings.

## Key concepts

* The `service` integration type imports a local JavaScript module from the worker project and calls its default export. The module ships in the same worker bundle.
* The `service_binding` integration type calls a separately deployed Worker through a Cloudflare service binding. The target Worker must be deployed independently and bound in `wrangler.toml`.
* Pre-process hooks run before the main integration and can short-circuit the request by returning a response. Use them for custom authorization, input validation, or request enrichment.
* Post-process hooks run after the main integration returns and can modify the response. The Auth0 callback post-process hook is the most common use case.
* When choosing between proxy and service execution, consider latency (service bindings avoid an external HTTP round-trip) and coupling (proxy keeps the backend independently deployable).

## Repo-grounded example

```json
{
  "serviceBindings": [
    { "alias": "hooks", "binding": "HOOKS" },
    { "alias": "target", "binding": "TARGET" }
  ],
  "paths": [
    {
      "method": "POST",
      "path": "/orders",
      "pre_process": { "binding": "hooks", "function": "before" },
      "integration": {
        "type": "service_binding",
        "binding": "target",
        "function": "run"
      }
    }
  ]
}
```

This snippet uses the `service_binding` integration type with Cloudflare bindings. The `serviceBindings` array maps aliases to binding names declared in `wrangler.toml`. The `pre_process` hook runs before the main integration, and the `integration.function` field specifies which method to call on the bound Worker.

## Troubleshooting

* If a `service` integration returns 500, confirm that the entrypoint path in the `services` array matches the actual file location relative to the worker root and that the module exports a default function.
* If a `service_binding` integration returns a binding error, verify that the binding name in config matches the binding declared in `wrangler.toml` and that the target Worker is deployed.
* If a pre-process hook does not short-circuit as expected, check that the hook function returns a `Response` object -- returning `undefined` or `null` lets the request continue to the main integration.
* If post-process hooks are not running, confirm the hook config uses the correct `binding` and `function` field names and that the hook Worker is deployed and bound.

## Related docs

* [service binding](/configuration/service-binding.md)
* [servers](/configuration/servers.md)
* [gateway troubleshooting matrix](/troubleshooting/wrangler-deploy-guide/gateway-troubleshooting-matrix.md)


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