API Contracts that Stay Predictable

Working on the data integration system taught me the importance of predictable API contracts. ## The Problem Multiple clients expected different response formats. Inconsistent error handling made debugging difficult. ## The Solution 1. **Define Schemas**: Use JSON Schema for request/response validation 2. **Standardize Errors**: Consistent error format across all endpoints 3. **Version APIs**: Support multiple versions for backward compatibility 4. **Document Everything**: Clear examples for each endpoint ## Key Principles - Always return the same structure - Use HTTP status codes correctly - Provide helpful error messages - Include request IDs for tracing This approach reduced integration time by 30% and improved client satisfaction significantly.