Versioning REST APIs with API Gateways

In this tutorial, you will learn about Versioning REST APIs with API Gateways. We cover key concepts, practical examples, and best practices to help you master this topic.

API gateways handle versioning at the infrastructure layer, routing requests to different backend services based on version, without changing application code.

Gateway Routing

API gateways can route based on URL prefix (/v1/, /v2/), header values (X-API-Version), or Accept header content types. This allows different versions to run on different infrastructure.

Kong Configuration

# Kong route for v1
routes:
  - name: users-v1
    paths: ["/v1/users"]
    service: users-service-v1

# Kong route for v2
routes:
  - name: users-v2
    paths: ["/v2/users"]
    service: users-service-v2

Common Mistakes

1. Gateway as single point of version logic — Application should still understand versioning.
2. No version preservation — Gateway strips version before forwarding.
3. Complex routing rules — Keep routing simple and predictable.

Practice Questions

1. How does an API Gateway help with versioning?
2. What versioning strategies work with gateways?
3. Why should the application still understand versions?

Challenge

Configure an API gateway to route /v1/ requests to a legacy service and /v2/ requests to a new service. Add header-based versioning as a fallback.

What's Next

In the next lesson, you will learn versioning Graphql APIs.