highlight.io

highlight.io is an open-source full-stack monitoring platform. Instead of stitching together separate tools for errors, logs, and traces, it puts session replay, error monitoring, log recording, and tracing into one view of the application stack. Session replay is the centerpiece: it captures console and network activity, so when a user encounters a bug you can watch exactly what happened rather than guessing from a stack trace. Error monitoring alerts you before an exception becomes a visible outage, with custom error grouping and configurable alert rules. Logs are searchable across the stack, and tracing shows performance for requests and transactions.

- Replay sessions with console and network detail

- Monitor errors with grouping and alert rules

- Search and alert on logs across the stack

- Trace request and transaction performance

- Build custom dashboards for observability data

- Developers debugging errors that only appear in production

- Product designers who need to understand real user behavior

- CTOs and engineering managers watching application health

A free trial is offered, but at scale you will need a paid plan or to self-host, so plan for cost and operations. Session replay captures user interactions by design, which means sensitive data like typed input can end up in recordings, so mask private fields and follow privacy rules. Integrating the SDK across the stack is real setup work, not a five-minute job, and incomplete integration produces incomplete data. Alerts need tuning, or noise will drown the useful indicator among thousands of events. Finally, replay and logs can grow large, so check retention and storage costs before traffic scales.