Error Tracking Node Agent Skill

PostHog error tracking for Node.js

This skill helps you add PostHog error tracking to Node.js applications.

Reference files

• references/node.md - Node.js error tracking installation - docs
• references/fingerprints.md - Fingerprints - docs
• references/alerts.md - Send error tracking alerts - docs
• references/monitoring.md - Monitor and search issues - docs
• references/assigning-issues.md - Assign issues to teammates - docs
• references/upload-source-maps.md - Upload source maps - docs

Consult the documentation for API details and framework-specific patterns.

Key principles

• Environment variables: Always use environment variables for PostHog keys and host URLs. Never hardcode them.
• Minimal changes: Add error tracking alongside existing error handling. Don't replace or restructure existing error handling code.
• Autocapture first: Enable exception autocapture in the SDK initialization before adding manual captures.
• Source maps: Upload source maps so stack traces resolve to original source code, not minified bundles.
• Manual capture for boundaries: Use captureException() at error boundaries and catch blocks for errors that don't propagate to the global handler.

Framework guidelines

• posthog-node is the Node.js server-side SDK package name – do NOT use posthog-js on the server
• Include enableExceptionAutocapture: true in the PostHog constructor options
• Add posthog.capture() calls in route handlers for meaningful user actions – every route that creates, updates, or deletes data should track an event with contextual properties
• Add posthog.captureException(err, distinctId) in the application's error handler (e.g., Express error middleware, Fastify setErrorHandler, Koa app.on('error'))
• In long-running servers, the SDK batches events automatically – do NOT set flushAt or flushInterval unless you have a specific reason to
• For short-lived processes (scripts, CLIs, serverless), set flushAt to 1 and flushInterval to 0 to send events immediately
• Reverse proxy is NOT needed for server-side Node.js – only client-side JavaScript needs a proxy to avoid ad blockers
• Remember that source code is available in the node_modules directory
• Check package.json for type checking or build scripts to validate changes