Instrument API requests with spans and distributed tracing. Use when tracking request latency, correlating client-backend traces, or debugging API issues.
Measure API requests and correlate with backend traces.
| Attribute | OTel Name | Purpose |
|---|---|---|
| Method | http.request.method | GET, POST, etc. |
| Status | http.response.status_code | Success/failure |
| URL | url.path | Endpoint (sanitized) |
| Duration | http.request.duration | Request time (ms) |
| Size | http.response.body.size | Payload bytes |
Using OTel naming = easier migration when OTel mobile matures.
See references/otel-mobile.md for rationale.
Propagate trace context to backend:
Client Request
│
├── traceparent: 00-{trace_id}-{span_id}-01
├── X-Request-Id: {uuid}
└── X-Session-Id: {session}
│
▼
Backend (correlates logs with trace_id)
| Metric | Good | Acceptable | Poor |
|---|---|---|---|
| API p50 | <500ms | <1s | >1s |
| API p95 | <2s | <5s | >5s |
| Error rate | <1% | <3% | >3% |
Choose based on existing vendor:
| Vendor | iOS | Android | Approach |
|---|---|---|---|
| Sentry | Auto URLSession swizzling | OkHttp integration | Automatic |
| Datadog | URLSession delegate | OkHttp interceptor | Semi-auto |
| Embrace | Auto-instrumentation | Auto-instrumentation | Automatic |
| Custom | Manual interceptor | Manual interceptor | Manual |
Automatic (swizzling): Less code, may miss custom clients Manual (interceptors): More control, works with any HTTP client
| Platform | Manual Option | Works With |
|---|---|---|
| iOS | URLSession delegate | All URLSession-based clients |
| iOS | Alamofire EventMonitor | Alamofire |
| Android | OkHttp Interceptor | OkHttp, Retrofit |
| Android | Ktor HttpClientPlugin | Ktor |
| RN | fetch wrapper | Native fetch |
| RN | axios interceptor | axios |
See references/mobile-challenges.md (Client-Backend Correlation) for:
See references/performance.md (Network section) for latency budgets.