Faultsense

Error tracking is quiet. RUM looks normal. The funnel dipped but won't say why. So you click through on desktop, then on mobile, then ask the user for a screen recording. Faultsense answers from the assertions you wrote, validated in real user sessions, per release, per cohort. Not a chart you have to read. A structured fact: assertion, release, cohort, pass/fail. Add assertions to your HTML. Real user sessions validate them in production, so you see which feature broke, for which users, on which release.