Node.js Logging with Pino and Winston

What is Logging with Pino and Winston in Node.js?

Structured logging writes machine-readable JSON with consistent fields instead of free-text strings, so logs can be searched, filtered and alerted on. Pino is the fast default; Winston is more configurable.

Logging with Pino and Winston example

import pino from 'pino';

export const logger = pino({
  level: process.env.LOG_LEVEL ?? 'info',
  redact: ['req.headers.authorization', 'password', '*.token'],
});

// one line per request, with a correlation id
app.use((req, res, next) => {
  req.id = crypto.randomUUID();
  req.log = logger.child({ reqId: req.id });
  next();
});

req.log.info({ jobId, userId }, 'application submitted');
req.log.error({ err }, 'failed to save application');

Key points to remember

• Log objects, not interpolated strings — the fields become searchable.
• Redact tokens, passwords and personal data before they reach the log.
• A correlation id per request lets you trace one user journey across many lines.
• Write to stdout and let the platform collect it; do not manage log files in the app.

Common mistakes with Logging with Pino and Winston

• console.log in production — no levels, no structure, no redaction.
• Logging entire request bodies, which leaks credentials into log storage.