Skip to main content

Crashless Documentation

Welcome to Crashless—production-ready observability for Node.js with zero npm dependencies.

🚀 Quick Start​

npm install crashless
import express from 'express';
import crashless from 'crashless';

const app = express();
app.use(crashless()); // That's it!

app.listen(3000);
// Dashboard: http://localhost:3000/_crashless

▶️ Try Interactive Examples

✨ Key Features​

🛡️ Automatic Error Handling​

Catch all errors automatically—no try-catch needed. Prevents server crashes from unhandled errors.

app.use(crashless());

// Async errors - automatically caught
app.get('/data', async (req, res) => {
  const data = await fetchData(); // 🛡️ Safe
  res.json(data);
});

📊 Built-in Dashboard​

Real-time observability dashboard with three powerful views:

  • System Dashboard - Request metrics, throughput, latency, route performance
  • Errors Dashboard - Error frequency, top failing routes, live error stream
  • Traces Dashboard - Request traces with waterfall visualization

Access: http://localhost:3000/_crashless

🔍 Distributed Tracing​

Automatic tracing for HTTP requests, fetch() calls, and fs.readFile() operations.

app.use(crashless({
  telemetry: {
    traces: {
      enabled: true,
      samplingRate: 0.2 // Sample 20% of requests
    }
  }
}));

Export traces: GET /traces.json?format=otlp - OpenTelemetry OTLP format

📈 OpenTelemetry Support​

Full OpenTelemetry compatibility for metrics and traces.

app.use(crashless({
  telemetry: {
    engine: 'otel' // OpenTelemetry format
  }
}));

Endpoints:

  • GET /metrics/otel - OpenTelemetry metrics
  • GET /traces.json?format=otlp - OTLP trace export

📊 Prometheus Metrics​

Prometheus-compatible metrics export for Grafana integration.

app.use(crashless({
  telemetry: {
    engine: 'prometheus'
  }
}));

Endpoint: GET /metrics - Prometheus format

🔌 Custom Exporters​

Integrate with Sentry, Datadog, or any monitoring service.

app.use(crashless({
  exporters: [
    {
      name: 'sentry',
      onError: (error, metadata) => {
        Sentry.captureException(error, { extra: metadata });
      }
    }
  ]
}));

⚡ Zero Dependencies​

Uses only Node.js built-ins. No external npm dependencies.

🔐 Production-Safe​

  • Sensitive data masked automatically
  • IP whitelist & token authentication
  • Dashboard disabled in production by default
  • Configurable overhead (2-30%)

🎮 Try It Live​

Interactive Examples:

📚 Documentation​

Getting Started​

Features & Integrations​

Advanced Topics​

🎯 Common Use Cases​

Minimal Setup (Error Handling Only)​

app.use(crashless({
  telemetry: { engine: 'none' }
}));

Overhead: ~3% | Use case: High-traffic apps needing only error handling

Standard Production​

app.use(crashless({
  telemetry: { engine: 'builtin' }
}));

Overhead: ~20% | Use case: Standard production with metrics

Production + Observability​

app.use(crashless({
  telemetry: {
    engine: 'builtin',
    traces: { enabled: true, samplingRate: 0.2 }
  }
}));

Overhead: ~27% | Use case: Full observability with distributed tracing

OpenTelemetry Integration​

app.use(crashless({
  telemetry: {
    engine: 'otel',
    traces: { enabled: true }
  }
}));

Use case: Integration with OTel collectors (Jaeger, Tempo, etc.)

Prometheus + Grafana​

app.use(crashless({
  telemetry: {
    engine: 'prometheus'
  }
}));

Use case: Prometheus scraping for Grafana dashboards

📊 Performance​

Crashless is designed for performance:

  • Minimal config: ~3% overhead vs plain Express
  • With metrics: ~20% overhead
  • Full observability: ~27% overhead (with 20% sampling)
  • 2.2x faster than express-async-errors

See Performance Guide for detailed benchmarks and optimization strategies.

🔗 Resources​

Next Steps​