ThumbLoop automatically A/B-tests your thumbnails inside YouTube Studio, keeps the winner, then loops in the next challenger — so your videos always run the best-performing thumbnail without you lifting a finger.
Works with YouTube's built-in Test & Compare. No channel access handed to anyone — it runs in your own browser.
Add a stack of candidate thumbnails to any video.
ThumbLoop starts YouTube's A/B test — your current thumbnail is never touched.
It checks every 6 hours and promotes a thumbnail that leads by more than 5%. No clear winner in 24 hours? It picks the leader so things keep moving.
The next challengers from your queue start a fresh test — automatically, until your queue runs out.
No. ThumbLoop runs as a Chrome extension in your own browser using your existing Studio session — we never receive your YouTube login or channel access. Your videos, queues and settings stay in your browser. The only data that ever leaves your machine is your Pro license key (sent to Lemon Squeezy to verify your subscription) and, only if you set it up yourself, swap alerts sent to your own Telegram. See our Privacy Policy.
Public videos longer than 6 minutes that have at least one queued thumbnail. Shorts, members-only, scheduled, and private videos are skipped automatically.
No — it checks every 6 hours and makes at most 8 changes a day, well within YouTube's limits.
Buy a Pro license and paste the key into the extension's Settings — Pro unlocks instantly, no reinstall. Cancel and it returns to Free automatically.