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concept#Architecture#Integration#Platform#Software engineering

API Architecture

A foundational concept for the structured design of interfaces, communication patterns, and integration boundaries between systems.

API architecture defines the structured design of interfaces, communication patterns, and integration boundaries between systems.
Established
Medium

Classification

  • Medium
  • Technical
  • Architectural
  • Intermediate

Technical context

API gateway (e.g. Kong, AWS API Gateway)Identity providers (OAuth2, OpenID Connect)Observability stack (Prometheus, Grafana, ELK)

Principles & goals

Clear API contracts and versioningConsistency in naming, error handling, and authenticationDesign APIs according to SLA, security, and scaling requirements
Build
Enterprise, Domain, Team

Use cases & scenarios

Compromises

  • Inconsistent implementations lead to integration issues
  • Insufficient security measures expose attack surfaces
  • Monolithic API gateways as single points of failure
  • Standardize error formats and status codes
  • Automate documentation and contract tests
  • Use canary releases and backward-compatible changes

I/O & resources

  • Domain and business requirements
  • Existing interface specifications
  • Security and compliance policies
  • API contracts and specifications
  • Deployment patterns and runbooks
  • Monitoring and SLA metrics

Description

API architecture defines the structured design of interfaces, communication patterns, and integration boundaries between systems. It prescribes principles for interface definition, versioning, security, error handling, and scalability. Design choices affect consistency, security, performance, and developer productivity and require clear governance to maintain a coherent API ecosystem.

✔

  • Improved reusability and decoupling of systems
  • Unified integration points reduce integration effort
  • Increased developer productivity through clear contracts and documentation

✖

  • Overhead from governance and documentation maintenance
  • Not all use cases fit a single interface pattern
  • Versioning and compatibility require process effort

  • Latency (p95)

    95th percentile response time to monitor performance SLAs.

  • Error rate

    Share of failed responses to detect stability issues.

  • Requests per second

    Measure of throughput for capacity planning.

RESTful service with OpenAPI

A service defines its interface using an OpenAPI specification and uses consistent error codes.

GraphQL gateway for composite queries

A gateway aggregates data from multiple microservices and exposes a unified query API.

Published partner API with OAuth2

Public API with OAuth2 flow, rate limits and detailed usage documentation for partners.

1

Inventory existing interfaces and requirements

2

Define conventions, security standards and versioning rules

3

Create sample specifications and SDK generation pipelines

4

Introduce governance, tests and observability

⚠️ Technical debt & bottlenecks

  • Unclear API contracts without tests
  • No automated documentation and SDKs
  • Monolithic gateway logic without modularization
LatencyThroughputAuth performance
  • Exposing internal data structures as API contract
  • Binding clients directly to non-stabilized endpoints
  • Bypassing authentication for development purposes in production
  • Underestimating effort for governance and training
  • Too fine-grained endpoints without performance strategy
  • Delayed deprecation communication to customers
API design and specification skills (OpenAPI, JSON Schema)Networking and security fundamentals (TLS, OAuth)Experience with observability and performance testing
Scalability under loadSecurity and access controlDeveloper productivity and reusability
  • • Legacy systems with limited modifiability
  • • Regulatory data protection requirements
  • • Budget and staffing limits for governance