error-tracking-nextjs

PostHog error tracking for Next.js

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

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

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.

For Next.js 15.3+, initialize PostHog in instrumentation-client.ts for the simplest setup
For feature flags, use useFeatureFlagEnabled() or useFeatureFlagPayload() hooks - they handle loading states and external sync automatically
Add analytics capture in event handlers where user actions occur, NOT in useEffect reacting to state changes
Do NOT use useEffect for data transformation - calculate derived values during render instead
Do NOT use useEffect to respond to user events - put that logic in the event handler itself
Do NOT use useEffect to chain state updates - calculate all related updates together in the event handler
Do NOT use useEffect to notify parent components - call the parent callback alongside setState in the event handler
To reset component state when a prop changes, pass the prop as the component's key instead of using useEffect
useEffect is ONLY for synchronizing with external systems (non-React widgets, browser APIs, network subscriptions)