How to Fix A/B Test Flicker (The Complete Anti-Flicker Guide)
· 5 min read
If you've ever run an A/B test and noticed visitors briefly see the original page before your variant loads, you've experienced FOOC — Flash of Original Content.
It's the most common technical problem in client-side A/B testing, and most tools either ignore it or implement a solution that creates a different problem (CLS, layout shift).
This is the complete guide to fixing it correctly.