Express.js Logging Integration

LogTide’s Express SDK provides drop-in middleware for automatic request logging, per-request context scoping, and distributed tracing with W3C Trace Context.

Why use LogTide with Express?

• Zero-config request tracing: Every HTTP request recorded as a span automatically, 5xx responses logged as errors
• Per-request scoping: Attach user, tenant, and custom tags to all logs in a request
• Distributed tracing: W3C traceparent headers propagated automatically
• Error capture: Errors captured with request context via logtideErrorHandler()
• Non-blocking: Logging never slows down your request handling

Prerequisites

• Node.js 18+
• Express 4.x or 5.x
• LogTide instance with a DSN

Installation

npm install @logtide/express

This includes @logtide/core as a dependency.

Quick Start

import express from 'express';
import { hub } from '@logtide/core';
import { logtide, logtideErrorHandler } from '@logtide/express';

const app = express();

// Add LogTide middleware (initializes LogTide automatically)
app.use(logtide({
  dsn: process.env.LOGTIDE_DSN,
  service: 'api-server',
  environment: process.env.NODE_ENV,
}));

app.get('/users/:id', (req, res) => {
  req.logtideScope?.setTag('userId', req.params.id);
  res.json({ id: req.params.id });
});

app.listen(3000);

Middleware Configuration

app.use(logtide({
  dsn: process.env.LOGTIDE_DSN,
  service: 'api-server',
  environment: process.env.NODE_ENV,
  release: '1.0.0',
  tracesSampleRate: 1.0,
}));

Per-Request Context

Attach context to all logs within a request:

app.use((req, res, next) => {
  if (req.user) {
    req.logtideScope?.setExtra('userId', req.user.id);
    req.logtideScope?.setExtra('email', req.user.email);
  }
  req.logtideScope?.setTag('tenant', String(req.headers['x-tenant-id']));
  next();
});

Trace Propagation

The middleware extracts incoming traceparent headers and makes the trace ID available:

app.get('/api/data', async (req, res) => {
  // Include trace ID in responses for debugging
  res.set('X-Trace-Id', req.logtideTraceId);
  res.json({ data: [] });
});

Error Handling

// The middleware records 5xx responses as error logs. To capture the
// thrown error itself, register logtideErrorHandler() after your routes:
app.use(logtideErrorHandler());

// Then your own error response handler:
app.use((err, req, res, next) => {
  res.status(err.status || 500).json({
    error: err.message,
    traceId: req.logtideTraceId,
  });
});

Request Tracing Output

Each request produces a span (sent as a trace) named after the method and path, for example GET /users/123, with attributes such as:

{
  "http.method": "GET",
  "http.target": "/users/123",
  "http.route": "/users/:id",
  "http.status_code": 200,
  "duration_ms": 45,
  "net.peer.ip": "192.168.1.1",
  "http.user_agent": "Mozilla/5.0..."
}

Responses with a 5xx status additionally produce an error log entry (HTTP 500 GET /users/123).

Next Steps

• JavaScript SDK - Core SDK reference
• Express SDK Reference - Full API documentation
• Docker Integration - Container deployments