Are there any on-premise alternatives to Sentry?

[_em6m]

What are HN users using as an on-premise alternative to Sentry? Why did you chose it? What problems did it solve that Sentry didn't?

[gjnoonan]

Sentry is open source, and you can run it on-prem https://sentry.io/_/open-source/

[bradknowles]

What is Sentry?