Open Source

See every log.
In real time.

Lightweight local log diagnostics for Node.js, Express, and NestJS. Real-time web UI, error tracing, breadcrumbs, and zero dependencies.

Get Started See it in action
dev-log-monitor - Real-time log monitor with zero setup for Node.js | Product Hunt
$ npm install dev-log-monitor click to copy
Copied!
app.ts
// One line. That's it.
import 'dev-log-monitor/auto';

// Every console.log is now captured with:
// • Source location • Timing deltas
// • Breadcrumbs • Stack traces
// • Data masking • Live web UI at :3333

console.log('It just works');
Features

Everything you need.
Nothing you don't.

Zero dependencies. Zero config required. Drop it in and get instant visibility into what your app is doing.

⚡
One-Line Integration
Just import 'dev-log-monitor/auto' — intercepts all console methods, starts the UI server, and enables masking. No setup.
📡
Real-Time Web UI
Beautiful log viewer at localhost:3333 with live WebSocket updates, filtering, search, dark/light themes, and keyboard shortcuts.
🔎
Source Location
Every log shows exactly where it was called — file, line, column, and function name. No more guessing which console.log fired.
🍞
Breadcrumbs
When an error occurs, see the last 10 logs that led to it. Understand the full context of what happened before the crash.
🔒
Sensitive Data Masking
Auto-redacts passwords, tokens, API keys, credit cards, SSNs, and 72+ sensitive fields. Add your own patterns too.
⏱
Timing & Metrics
See timing deltas between logs, measure operations with timers, and track error rates, log frequency, and slow operations.
🚧
Parsed Stack Traces
Stack traces are parsed into clickable frames. Your app code is highlighted, node_modules are collapsed.
🔌
Works With Any Logger
Console, Winston, Pino, Bunyan — all captured automatically. Or use the built-in scoped logger for structured logging.
🚨
Alerts & Webhooks
Get notified when error rates spike, patterns match, or operations are slow. Send alerts to webhooks, desktop, or custom handlers.
Quick Start

Up and running in 30 seconds

Three steps. No config files. No build plugins. Just install, import, and open the browser.

1

Install

Add the package to your project. Zero dependencies means nothing else to install.

$ npm install dev-log-monitor
2

Import

Add one line at the top of your entry file. That's it — everything is automatic.

// app.ts (or server.ts, index.ts, main.ts)
import 'dev-log-monitor/auto';

// your existing code below...
3

Open the UI

Start your app and open the log viewer in your browser. Logs stream in real time.

$ npm run dev

// Open http://localhost:3333
Live Preview

Your logs, visualized

Every log entry is enriched with source info, timing, context, and more — all searchable and filterable.

http://localhost:3333
Filters
Metrics
Total Logs
0
Error Rate
0.4/min
Avg Response
42ms
09:41:02 info Server started on port 4000 +0ms
09:41:02 debug Database connection pool created (min:2, max:10) +12ms
09:41:03 info GET /api/users 200 — 45ms +1.2s
09:41:03 debug Cache hit: users_list (150 keys) +3ms
09:41:04 warn Deprecated API called: /v1/users → use /v2/users +890ms
09:41:05 info POST /api/orders 201 — 230ms +1.1s
09:41:05 error Payment failed: Card expired (****4242) +340ms
09:41:06 info Notification sent: order_confirmation (user@***) +520ms
Configuration

Configure with env vars

No config files needed. Everything is configurable via environment variables — perfect for Docker, CI, and .env files.

Variable Default Description
DEV_LOG_PORT 3333 Port for the web UI
DEV_LOG_DIR .dev-log Log storage directory
DEV_LOG_RETENTION 3 Days to keep log files
DEV_LOG_CONSOLE true Also print logs to console
DEV_LOG_INTERCEPT true Intercept console.log/warn/error
DEV_LOG_MASKING true Auto-mask sensitive data
DEV_LOG_STORAGE_LEVEL debug Minimum level to persist (debug | info | warn | error)
DEV_LOG_MAX_FILE_SIZE 52428800 Max per-file size in bytes (50MB)
DEV_LOG_MAX_TOTAL_SIZE 104857600 Max total storage in bytes (100MB)
DEV_LOG_DISABLE false Disable dev-log entirely
NODE_ENV — Set to production to auto-disable

Start seeing your logs

Install in seconds. Remove in seconds. Zero lock-in.

Install Package View on GitHub