Logs, Metrics & Traces

Make production behavior measurable so engineers can answer what happened, where and why.

Lesson overview

Logs, metrics and traces answer different questions. Structured logs explain events, metrics reveal trends and traces connect work across services. Avoid sensitive data and uncontrolled metric cardinality.

Learning path

Theory → Example → Code → Practice → Quiz → Challenge → Completion

0/6 done

Step 1

Theory

Step 2

Example

A checkout trace can show whether latency comes from the API, database or payment provider instead of relying on guesswork.

Step 3

Code

typescript
logger.info({
event: "payment.authorized",
orderId,
requestId,
providerLatencyMs,
});

Step 4

Practice

Review your current application and apply Logs, Metrics & Traces. Document the current behavior, one production risk, the change you would make, and how you would verify it.

Step 5

Quiz

1. What is the central production concern in "Logs, Metrics & Traces"?

Step 6

Challenge

Design a production-ready implementation for Logs, Metrics & Traces. Include failure handling, security considerations, observability, testing and a rollback or recovery path where applicable.

Complete every stage

Work through every step in order, then the lesson will be marked complete.

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Each chapter and subtopic has its own public URL under /full-stack-to-production.