Routing Policies

What are Routing Policies?

Routing policies in API Gateway determine the direction of incoming requests to different backend resources or endpoints based on specified conditions. These policies allow you to control the flow of traffic within API Gateway, enabling you to implement various routing strategies, such as load balancing, versioning, A/B testing, and canary deployments.

Straight Through Routing policy is applied by default when an API is created in API Gateway. This default behavior is suitable for APIs that route incoming requests to a single backend resource or native endpoint.

Let’s look at a sample scenario, where you are importing https://petstore.swagger.io/v2/swagger.json URL to create the Petstore REST API, and Straight Through Routing policy is applied by default.

Before you begin

Ensure that you have

To configure Straight Through Routing policy

  1. Click APIs in the title navigation bar.

  2. Click Create API.

  3. Select Import API from URL.

  4. Provide the following information:

  5. Click Create. The Petstore API is created, and the Straight Through Routing policy is applied by default. The Petstore API’s details page appears.

  6. Click Activate to activate the API.

  7. To check the Straight Through Routing policy that is applied by default, click Policies > Routing.

In this example, the default application of Straight Through Routing policy simplifies the API configuration process.

Once the Petstore API is configured and exposed, clients can interact with the API endpoints to perform various actions, such as retrieving a list of available pets, adding new pets to the store, updating pet details, placing orders, and more. API Gateway directly routes each API request made by the client to the backend service.

The following table lists the routing policies offered by API Gateway and outlines the specific use cases for each policy:

Use case Routing policy
Objective: Expose existing backend services through an API with minimal added complexity.

Scenario: Optimize traffic flow between network segments or zones without intermediate processing.

Example: In fast networks like data centers, straight-through routing minimizes latency and overhead. This approach ideally suits applications that require low latency and high throughput, such as real-time video streaming, online gaming, or financial trading.		 Utilize Straight Through Routing policy to ensure minimal latency and overhead.
Objective: Direct incoming requests to different backend resources based on specified conditions or criteria.

Scenario: Handling sensor data from various devices differently based on specific conditions.

Example: In a smart agriculture system, sensors monitor soil moisture levels across different fields. Conditional routing directs data from sensors detecting low moisture levels to irrigation systems for immediate action.		 Utilize Conditional Routing policy to handle data differently depending on predefined conditions.
Objective: Effectively distribute incoming network traffic evenly across multiple servers or resources to optimize resource utilization and improve system performance.

Scenario: Handling high volumes of incoming requests in a web hosting environment.

Example: During peak shopping seasons, an e-commerce platform utilizes load balancer routing to evenly distribute traffic across servers, preventing overload and enhancing performance for a seamless user experience.		 Utilize Load Balancer Routing policy to evenly distribute incoming requests across servers.
Objective: Ensure secure communication between API Gateway and backend systems by including authentication credentials within transport headers.

Scenario: Integration with legacy systems or third-party APIs requiring transport-level authentication.

Example: An enterprise application interacts with a legacy backend protected by Basic Authentication over HTTPS.

Configuring the Outbound Auth - Transport policy with the appropriate credentials enables API Gateway to seamlessly authenticate and authorize outgoing requests to the legacy system.		 Utilize Outbound Auth – Transport policy to authenticate outgoing requests.
Objective: Embed authentication credentials within the payload message of outgoing requests to satisfy requirements of the native API.

Scenario: In instances where APIs mandate authentication credentials within the message payload.

Example:An application needs to interact with a third-party service secured with SAML-based authentication.

By configuring the Outbound Auth - Message policy with the necessary SAML credentials, API Gateway seamlessly embeds these credentials within the outgoing request’s payload, ensuring secure communication without added complexity.		 Utilize Outbound Auth – Message policy to embed authentication credentials within the message payload for secure communication with APIs.
Objective: Facilitate seamless communication between a legacy system utilizing a JMS queue and a modern RESTful API.

Scenario: Modernizing service by offering a RESTful API for order placement while maintaining compatibility with legacy JMS-based communication.

Example: A legacy system communicates through a JMS queue for order processing. The company aims to modernize its service by providing a RESTful API for order placement.

JMS/AMQP routing policy acts as a bridge between the legacy system and the RESTful API, ensuring smooth transition and compatibility.		 Utilize JMS/AMQP Routing policy to seamlessly route requests between the two environments.