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How do you implement structured logging with pino or winston, and why avoid console.log in production?

Q: How do you implement structured logging with pino or winston, and why avoid console.log in production?

**TL;DR.** Structured loggers like **pino** emit **JSON** with levels, timestamps, and context — so logs are **machine-parseable** and queryable in aggregators. console.log is **synchronous**, unstructured, and can **block** under load; pino is asynchronous and far faster, and pairs with AsyncLocalStorage for per-request fields. console.log('user', id) ❌ unstructured, sync log.info({{ userId }}, 'login') ✅ JSON, async, leveled <path class=

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JSON logs, levels, and async transport performance.

nodejsloggingpinoobservability

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Pino with per-request context

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

app.use((req, res, next) => {
  req.log = logger.child({ reqId: crypto.randomUUID(), path: req.path });
  next();
});
app.get('/x', (req, res) => { req.log.info({ userId: 42 }, 'handled'); res.end(); });
// → {"level":"info","reqId":"...","path":"/x","userId":42,"msg":"handled"}

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