Datadog vs Prometheus

const tracer = require('dd-trace').init({
  service: 'my-service',
  env: process.env.NODE_ENV,
  version: process.env.APP_VERSION,
});

// Auto-instrumentation — just init at startup
// Traces, spans, and logs flow automatically

# prometheus.yml
global:
  scrape_interval: 15s

scrape_configs:
  - job_name: 'my-app'
    static_configs:
      - targets: ['localhost:3000']

# Expose metrics from Node.js
const client = require('prom-client');
const httpRequests = new client.Counter({
  name: 'http_requests_total',
  help: 'Total HTTP requests',
  labelNames: ['method', 'status'],
});