An API gateway owns cross-service entry-point concerns#
As a product splits into services, public clients should not need every internal address or authentication convention. A gateway provides an application-aware entry point and routes requests to the responsible service.
Responsibilities can include routing, authentication and authorization integration, rate limiting, version handling, request transformation, aggregation, and entry-point observability. Business invariants should remain in the owning service rather than accumulating in the gateway.
Gateway and load balancer are conceptual roles#
| Role | Primary question |
|---|---|
| Load balancer | Which healthy instance of this target should receive traffic? |
| API gateway | Which API/service owns this request, and which cross-cutting policies apply? |
Real products may implement both roles together. Avoid presenting them as mutually exclusive product categories.
Related practice problems
Use the manifest-backed prompts below to apply this lesson in a complete design.
- Gateway Routing patternAzure Architecture Center
Reach this point to mark the lesson as read.