# Connect spans with one trace ID and route label.

> Model TrafficWar traces across HTTP, database, Redis, and S3 tiers using trace_id, label, source, span_kind, and operation_type.

A trace is a group of ordinary TrafficWar events. Share one trace_id and label across the request and describe each tier with its normal event fields.

## Example multi-tier trace



```typescript
const trace_id = crypto.randomUUID();
const label = "/checkout";

trafficwar.capture([
  { event: "database", label, trace_id, source: "db-primary",
    operation_type: "postgres.select", span_kind: "client", latency_ms: 12.4 },
  { event: "s3", label, trace_id, source: "receipts.ovh-s3",
    operation_type: "s3.put_object", span_kind: "client", latency_ms: 18.3 },
  { event: "http", label, trace_id, source: "checkout-api",
    operation_type: "route.handler", span_kind: "server", latency_ms: 96.1 },
  { event: "http", label, trace_id, source: "web", http_method: "POST",
    operation_type: "http.request", span_kind: "client", latency_ms: 184.2,
    status_code: 200 },
]);
```

## Keep the hierarchy valid

Emit dependency spans before the backend and edge span when sending one array. Inclusive durations should nest: dependency time must not exceed backend time, and backend time must not exceed the edge request.

## S3 source convention

For S3, source is a provider alias such as ovh-s3, aws-s3, or minio. Use bucket.provider, such as receipts.ovh-s3, only when separate bucket stations are useful. The operation_type remains the operation dot.

## Related

- [Rebuild one request across edge, backend, and dependencies.](https://trafficwar.tech/features/distributed-tracing.md)
- [Watch requests move through every application tier.](https://trafficwar.tech/features/live-map.md)
- [Use stable event identities that stay useful at scale.](https://trafficwar.tech/docs/event-schema.md)