My 6-point QA before any test goes live

My 6-point QA before any test goes live

Shipped a broken variant once. Burned 4 days of traffic on a CTA that 404'd on mobile. Never again. Now I run this before I hit start:

— Load variant B in incognito. Hard refresh. Does it actually look different?
— Resize browser to 375px. The mobile users are 60% of my traffic and they break first.
— Click the CTA. Confirm it fires the conversion event in real-time analytics.
— Check both variants share the SAME goal definition. Mismatched goals = garbage data.
— Throttle network to Slow 3G in devtools. Flicker = original flash = ruined test.
— Screenshot both. Side by side. Eyeball it.

Takes 8 minutes. Saves a week.

Go run this checklist on the test you're about to launch. Don't skip step 5.