What is a first party crash vs. a third party crash?

A first party crash is a crash that originated in a source file that is a part of your website while a third party crash is a crash that originated in a source file from a different domain than your websites’.

For instance, if your website exists at mysite.com, and the error came from the source file js.mysite.com/my/site, then the crash is considered first party.

If the source file was hosted on a different domain entirely, for example, mysocialmediasite.com/widget.js, it would be considered third party.

Whether a domain belongs to your website or not depends on the URLs you enter in the configuration for your website in Matomo.