I consume a lot of public JSON APIs, and the worst failure mode is the one that never throws: the feed still returns HTTP 200 but the shape has quietly changed. A field gets renamed. The item count drops from 800 to 12 overnight. A salary key disappears. An endpoint starts returning an empty array. None of it is an error — your HTTP client is happy — so a plain status-code health check says "all good" while your data is already broken. That is the gap jobfeed-watchdog (JFW) fills: a s...