What is API Design?
API design is the practice of defining the interface through which software components communicate.
API design is the practice of defining the interface through which software components communicate. Good API design creates clear, consistent, well-documented contracts that are easy to use correctly and hard to use incorrectly.
Key principles: consistency (similar operations work similarly), simplicity (minimal surface area), versioning (backward compatibility), error handling (clear, actionable error messages), and documentation (complete, accurate, with examples).
Common patterns: REST (resource-oriented), GraphQL (query-based), gRPC (performance-oriented), WebSocket (real-time). Each has trade-offs for different use cases.
Why It Matters
Poor API design creates integration debt — every consumer of a bad API builds workarounds that compound maintenance burden. APIs are contracts; changing them is expensive and risky.
How to Measure
Track API adoption rate, time-to-first-successful-call, error rate by endpoint, breaking change frequency, and developer satisfaction scores.
Frequently Asked Questions
REST vs GraphQL vs gRPC?
REST for most web APIs (simple, well-understood). GraphQL for complex data needs (mobile apps, multiple consumers). gRPC for high-performance internal services. Most organizations use multiple patterns.
Related Terms
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