Routing: Multiple Upstreams Behind One Domain

Split one public API domain across several backends while keeping routing rules readable. Define multiple server aliases in the `servers` array and reference

Split one public API domain across several backends while keeping routing rules readable. Define multiple server aliases in the servers array and reference each one from the appropriate path entry. This pattern is common when migrating from a monolith to microservices behind a single gateway.

Last reviewed: 2026-03-06

When to use this

Use the routing guides when you need to understand how the gateway matches incoming requests to configured paths. Routing is the core behavior of the gateway -- every request passes through the path matcher before reaching an integration, auth check, or static response.

Key concepts

• The gateway supports three route shapes: exact paths (/health), parameterized paths (/users/:id), and wildcard paths (/proxy/{.+}). Exact matches take highest priority.

• When multiple routes could match a request, the gateway uses a fixed priority order: exact > parameterized > wildcard. This is not configurable.

• The method field accepts standard HTTP methods (GET, POST, etc.) as well as ANY, which matches all methods on that path.

• Prefix add/remove rules transform the path before forwarding to the upstream, letting you decouple public API structure from backend path layout.

• Static response routes skip integration entirely and return the response field directly, which is useful for health checks and feature flags.

Repo-grounded example

{
  "servers": [
    { "alias": "upstream", "url": "https://api.example.com/base" }
  ],
  "paths": [
    {
      "method": "GET",
      "path": "/proxy/{.+}",
      "integration": {
        "type": "http_proxy",
        "server": "upstream"
      }
    }
  ]
}

This snippet shows a single upstream server definition. To route different paths to different backends, add more entries to the servers array with distinct aliases and reference them in each path's integration.server field.

Troubleshooting

• If a request hits the wrong route, check whether a wildcard pattern is matching before your intended exact or parameterized route -- exact always wins over wildcard.

• If an OPTIONS request returns unexpected results, verify whether you have an explicit OPTIONS handler for that path or are relying on the default CORS 204 behavior.

• If prefix removal produces a double-slash in the upstream URL, confirm that both the remove_prefix and the upstream url do not include trailing/leading slashes that conflict.

• Use wrangler tail and look at the matched path in the log output to confirm which route config entry the gateway selected.

Related docs

• README

• add and remove prefix

• gateway troubleshooting matrix