Congrats on the open-source move! It's always good to see more players in the OSS space.
We do track JS errors at OpenReplay and of course link them to recordings. Errors come with stacktraces, are also fully searchable and can be used as cards to build custom dashboards.
In terms of backend errors, we took a different approach at OpenReplay. We pull them from third-party systems (i.e. Sentry, Elastic, CloudWatch, Datadog, etc.) and sync them with the corresponding replays.
