Structured logging in Next.js with pino: why the request ID is the whole point

Oliver White

4 May 2026 · 6 min read

// lib/logger.ts
import pino from 'pino';

export const logger = pino({
  level: process.env.LOG_LEVEL ?? 'info',
  // pino-pretty for human-readable dev output, raw JSON in production
  transport: process.env.NODE_ENV === 'development'
    ? { target: 'pino-pretty', options: { colorize: true } }
    : undefined,
});

export function generateRequestId(): string {
  return `req_${Date.now()}_${Math.random().toString(36).slice(2, 9)}`;
}

// app/api/v1/vote/route.ts — the full logging pattern
export async function POST(request: Request) {
  const requestId = generateRequestId();
  const start = Date.now();

  logger.info({ requestId }, 'vote request received');

  // ... validation, rate limiting ...

  const { data, error } = await supabase.rpc('submit_vote', { ... });

  if (error) {
    logger.error({ requestId, error: error.message, durationMs: Date.now() - start }, 'rpc failed');
    return NextResponse.json({ error: 'Internal server error' }, { status: 500 });
  }

  logger.info(
    { requestId, success: data[0].success, errorCode: data[0].error_code, durationMs: Date.now() - start },
    'vote request complete'
  );

  return NextResponse.json({ success: true, vote_count: data[0].vote_count });
}

Include requestId in the response as an X-Request-Id header. This lets you correlate a client-side error (the user screenshots the browser console) with the server-side log entry — no guessing which of 50 concurrent requests failed.

Built with this methodology

A Sentry stack trace tells you what broke. A structured pino log with a request ID tells you everything else: which request, what input, how long it ran, what preceded the failure. Here is how to build that in Next.js API routes.