API Error Handling Best Practices

Good error handling is the difference between a flaky integration and a production-ready one. This guide covers patterns for handling every type of API error gracefully.

Step 1: Understand Error Categories

API errors fall into three categories:

• Client errors (4xx) — Your request is wrong. Fix the request.
• Rate limits (429) — Slow down. Retry with backoff.
• Server errors (5xx) — Temporary. Retry automatically.

Step 2: Implement Retry Logic

async function withRetry(fn, maxRetries = 3) {\n for (let i = 0; i <= maxRetries; i++) {\n try {\n return await fn();\n } catch (err) {\n if (i === maxRetries || err.status < 500) throw err;\n const delay = Math.pow(2, i) * 1000 + Math.random() * 1000;\n await new Promise(r => setTimeout(r, delay));\n }\n }\n}

Step 3: Add Circuit Breaker

Prevent cascading failures by stopping requests when error rate is too high.

Step 4: Map Errors to User Messages

Never show raw API errors to users. Map error codes to friendly messages.

Step 5: Log and Monitor

Log all API errors with request context (endpoint, params, response time). Set up alerts for elevated error rates.