The Deployments tab is where an application's releases live: the one running now, and the history you can go back to.
Deploy
Select Deploy to build and release the current source and settings. From the deploy menu you can also deploy with a specific builder for one run without changing the app's default. A deploy is health-gated: the old release keeps serving until the new one is ready, so a failed deploy does not take the app down.
Roll back
Each release is numbered v1, v2, and so on, and shows its build, its commit,
and its status (Live, Superseded, Failed). To return to an earlier
one, select Roll back to that version. A rollback redeploys that release
exactly as it was, including the variables,
start command and port it was deployed with, because a release freezes its
configuration.
Restart
Restart replaces the running instance with a fresh one on the same release. It does not rebuild and does not change anything; use it to clear a stuck process or pick up something that only reads its environment at startup.
Cancel a build
While a build is still running, Cancel build stops it. The release that was already running is unaffected.
Deploys from a GitHub push
If the app deploys from GitHub with Deploy on push, a push to its branch deploys it the same way, and shows up here as a new release.