If you’ve ever been asked, “Conversions for XYZ are down. Did something break on the site?” this might resonate.

Fault Sense is the library I wish existed to answer the kinds of questions product analytics and tracing tools can’t: when something should happen, but doesn’t. Tracing tools get close, but they’re heavy and invasive to instrument.

Fault Sense stays lightweight. It’s language and framework agnostic — drop in a script tag, annotate your HTML, and you’re done. It lives at the edge of your application and can be turned off just by removing the script tag.

It’s still a work in progress, but I’d love feedback if you’ve faced similar “is it broken?” moments.