#Hydration Validation

Hydration validation proves that the built page works in a real browser, not only in static build output.

#What to Validate

A complete frontend production smoke should check:

• page returns HTML
• JS/CSS/assets return 2xx
• no browser console errors
• no page errors
• route-specific modulepreload exists
• hydration marker reaches done
• performance.measure("vext:hydration") exists
• size-report.json contains route metrics

#Browser Probe

The external consumer project provides a probe:

npm --prefix E:\Worker\vext-test run verify:frontend-performance

It builds the app, starts a production server for the test, opens pages with Playwright, records network failures, reads DOM markers, reads Performance API entries, and closes the server.

#Runtime Signals

Expected client-side signals:

data-vext-hydration="done"
performance.measure("vext:hydration")

These are intended for tests and diagnostics. They should stay quiet in production logs.

#Common Failures