Lesson 5 · Undo
Safety: Instant Rollback
You open: Vercel project overview → Instant Rollback
Every previous production deployment is kept. Putting yesterday’s site back in the window is one click. After a rollback, new pushes will not go live until you Undo Rollback. That catch is the rest of the lesson.
Instant Rollback points the production domain at an older Ready deployment. It does not rewrite GitHub history. The “bad” commit is still in the cabinet; the window just shows an earlier mold.
Vercel then turns off auto-assignment of the production domain, so a new push cannot immediately re-break the site you just restored. When the emergency is over, Undo Rollback (promote a deployment) so ordinary deploys resume.
Hobby plans can roll back to the immediately previous production deployment. That is enough. Practice on a harmless change, not during a real fire.
Practice
Run the drill below once: ship a bad number, roll back, notice auto-assign is off, then undo. On the real project, find the Instant Rollback control without clicking Confirm.
Production: correct number
The live slot shows the current Ready deployment.
Takeaway. Rollback is one click. Afterward, Undo Rollback or new pushes stay off the live domain.
From the experts
- Vercel: Instant Rollbackhomework
Opening this lesson counts as done.