APIBackends

APIBackends refer to the collection of backend services that implement the logic, data access, and integrations required to fulfill API requests issued by clients. They are distinct from API clients or front-end components and form the server-side core of an API-driven architecture. In a typical setup, APIBackends can include microservices, serverless functions, legacy systems, and database layers that expose programmatic interfaces to external or internal consumers.

An API gateway or edge router sits in front of APIBackends, handling authentication, rate limiting, request shaping, protocol translation, and routing. The gateway may aggregate results from multiple backends, enforce security policies, and provide a stable interface to clients.

Key design principles include statelessness, clear service contracts with versioning, idempotent operations, and robust error handling. Observability through metrics, logs, and distributed tracing is essential, and strategies such as retries, timeouts, and circuit breakers help tolerate downstream failures.

Security and data consistency considerations also shape APIBackends. Authentication and authorization controls, encryption in transit, least-privilege access, and audit logging are common requirements. Depending on the domain, backends may implement strong consistency with transactions or employ eventual consistency with compensating actions.

Examples include user-profile services, payment processing, search indexes, and inventory trackers. Related concepts include API gateways, service meshes, and backend-as-a-service offerings.