Sentry

Sentry is the error tracking platform that most startups set up on day one and never replace. Stack traces, breadcrumbs, release tracking, performance monitoring, and session replay — it catches bugs before your users report them. The commercial SaaS is mature and genuinely useful.

GlitchTip is the open-source, Sentry-compatible drop-in replacement — runs on a $5/month VPS with 30x less RAM than self-hosted Sentry. Highlight.io combines error tracking with session replay beautifully. But neither matches Sentry's breadth: integrations, alerting rules, and issue management are years ahead.

Use Sentry's free tier (5k errors/month) for any project. It's genuinely generous for indie hackers and small teams.

The catch: Sentry's "Other" license is BSL-derived — you can self-host but can't build a competing product. Self-hosted Sentry requires Kafka, ClickHouse, PostgreSQL, Redis, and a dozen worker processes — it's not a simple Docker Compose deploy. And pricing scales fast once you exceed the free tier. If all you need is "catch errors and alert me," GlitchTip at 1/30th the resources is the better self-hosted choice.