Connecting systems with precision

API-first design means defining the API contract, what requests it accepts, what it returns, what errors it produces, before writing any implementation code. This forces clarity about what the system needs to do, enables parallel development and produces consistent, intentional APIs.

In event-driven architecture, systems publish events when something happens, and other systems subscribe and react, without the publisher knowing who is listening. It's better when multiple systems need to react to the same event or when the system needs to handle high throughput asynchronously.

Synchronous means System A waits for System B's response before continuing. Asynchronous means System A continues without waiting. Synchronous is simpler but creates tight coupling. Asynchronous is more resilient and scales better but requires more infrastructure.

An API gateway sits in front of backend services and handles cross-cutting concerns, authentication, rate limiting, routing, logging and protocol translation, enforcing consistent security policies across all APIs.

API lifecycle management covers the full lifespan of an API: design, documentation, versioning, monitoring, deprecation and retirement. Without it, APIs accumulate breaking changes that silently fail consumers.