Working with routes for HTTP APIs - Amazon API Gateway

Working with routes for HTTP APIs

Routes direct incoming API requests to backend resources. Routes consist of two parts: an HTTP method and a resource path—for example, GET /pets. You can define specific HTTP methods for your route. Or, you can use the ANY method to match all methods that you haven't defined for a resource. You can create a $default route that acts as a catch-all for requests that don’t match any other routes.

Working with path variables

You can use path variables in HTTP API routes.

For example, the GET /pets/{petID} route catches a GET request that a client submits to https://api-id.execute-api.us-east-2.amazonaws.com/pets/6.

A greedy path variable catches all child resources of a route. To create a greedy path variable, add + to the variable name—for example, {proxy+}. The greedy path variable must be at the end of the resource path.

Working with query string parameters

By default, API Gateway sends query string parameters to your backend integration if they are included in a request to an HTTP API.

For example, when a client sends a request to https://api-id.execute-api.us-east-2.amazonaws.com/pets?id=4&type=dog, the query string parameters ?id=4&type=dog are sent to your integration.

Working with the $default route

The $default route catches requests that don't explicitly match other routes in your API.

When the $default route receives a request, API Gateway sends the full request path to the integration. For example, you can create an API with only a $default route and integrate it on the ANY method with the https://petstore-demo-endpoint.execute-api.com HTTP endpoint. When you send a request to https://api-id.execute-api.us-east-2.amazonaws.com/store/checkout, API Gateway sends a request to https://petstore-demo-endpoint.execute-api.com/store/checkout.

To learn more about HTTP integrations, see Working with HTTP proxy integrations for HTTP APIs.

Routing API requests

When a client sends an API request, API Gateway first determines which stage to route the request to. If the request explicitly matches a stage, API Gateway sends the request to that stage. If no stage fully matches the request, API Gateway sends the request to the $default stage. If there's no $default stage, then the API returns {"message":"Not Found"}.

After selecting a stage, API Gateway selects a route. API Gateway selects the route with the most-specific match, using the following priorities:

  1. Full match for a route and method.

  2. Match for a route and method with a greedy path variable ({proxy+}).

  3. The $default route.

If no routes match a request, API Gateway returns {"message":"Not Found"} to the client.

For example, consider an API with a $default stage and the following example routes:

  1. GET /pets/dog/{id}

  2. GET /pets/{proxy+}

  3. ANY /{proxy+}

  4. $default

    The following table summarizes how API Gateway routes requests to the example routes.

Request Selected route Explanation

GET https://api-id.execute-api.region.amazonaws.com/pets/dog/1

GET /pets/dog/{id}

The request fully matches this route.

GET https://api-id.execute-api.region.amazonaws.com/pets/cat/1

GET /pets/{proxy+}

The request doesn't fully match a route. The route with a GET method and a greedy path variable catches this request.

POST https://api-id.execute-api.region.amazonaws.com/test/5

ANY /{proxy+}

The ANY method matches all methods that you haven't defined for a route. Routes with greedy path variables have higher priority than the $default route.