Node.js Structured Logging in Production: Pino, Correlation IDs, and Log Aggregation

console.log works until it doesn't. In production, you need to answer questions like: "Why did this request fail for user 4821 at 3:14am?" — and console.log('error:', err) gives you nothing to search, filter, or correlate. This guide covers structured logging with Pino — the fastest Node.js logger — including request correlation, child loggers, log level management, and shipping logs to your aggregation stack. Why Pino Node.js logging libraries range from the veteran ( winston ) to the minimal ( debug ). Pino wins for production on throughput: Library ops/sec Notes pino ~7,000,000 JSON, minimal overhead winston ~200,000 Flexible, popular bunyan ~300,000 JSON, older API console.log ~1,000,000 No structure, no levels Pino achieves speed by writing JSON synchronously to stdout and delegating all formatting, filtering, and transport to a separate worker process. Your application code never blocks on log I/O. Basic Setup npm install pino pino-pretty // lib/logger.js const pino = require ( '