Telemetry is the automated collection, transmission, and analysis of data from remote systems to monitor their performance, health, and behavior. In software engineering, telemetry encompasses the metrics, logs, traces, and events that applications and infrastructure emit during operation. This data provides visibility into how software behaves in production, enabling teams to detect issues, optimize performance, and make informed decisions about system improvements.
Modern telemetry typically includes three pillars of observability:
- Metrics: Numerical measurements over time, such as CPU usage, memory consumption, request latency, and error rates.
- Logs: Structured or unstructured text records of events that occur within an application.
- Traces: End-to-end records of requests as they propagate through distributed systems, showing timing and dependencies across services.
Telemetry is collected using instrumentation libraries and agents, then sent to platforms like Prometheus, Grafana, Datadog, New Relic, or OpenTelemetry-compatible backends for storage and visualization. OpenTelemetry has emerged as the industry standard for vendor-neutral telemetry instrumentation, providing consistent APIs and SDKs across languages and frameworks. Good telemetry enables alerting on anomalies, root cause analysis during incidents, capacity planning, and continuous performance optimization.
Building telemetry into applications from the start is worth the effort. It gives development and operations teams the visibility they need to maintain reliability, troubleshoot issues quickly, and make sure software meets its performance objectives in production.