Cascra

The hero is a working trace, not a screenshot. A checkout request is traced across 13 spans on a millisecond ruler. Visitors hover any span to read its timing, click the slow one to open the root cause (23 database queries drawn as a staircase, with the diff that fixes it), then ship the fix: every later span moves left, the request drops from 1,284 ms to 428 ms, and the p95 chart falls back under its SLO.