Sentry
Sentry turns noisy stack traces into actionable bugs — see errors, latency spikes, and slow renders in one debugger-first dashboard.
Sentry is the de-facto standard for error monitoring and application performance monitoring, pairing debugger-first stack traces with tracing, session replay, and its Seer AI debugger. A genuinely usable free tier and the founder deal make it an easy Buy; usage-based quotas are the only thing to watch as you scale.