API integration architecture is the design discipline for connecting enterprise systems through structured interfaces. REST APIs provide standard HTTP-based communication. GraphQL enables flexible data querying. Event-driven architecture (Kafka, Event Hubs) handles asynchronous, high-volume data flows. API gateways (Azure APIM, AWS API Gateway) provide rate limiting, authentication, and monitoring.
Enterprise integration architecture requires: API design standards (OpenAPI specification, versioning strategy, error handling), security (OAuth 2.0, mTLS, API key management), gateway patterns (rate limiting, caching, circuit breaking), and monitoring (latency tracking, error rates, usage analytics).