"The build failed": what it means

After the builder writes code, the platform compiles it. If the compile fails, the exact error goes straight back to the builder, which rewrites the affected files and tries again in the same turn. You do not need to do anything.

If it keeps failing

• Send a short message: the build is failing, please fix it. The builder reads the current error and the files it names.
• Restore the previous version from version history and ask for the change again in smaller steps. See Restoring an earlier version.
• If you edited code yourself in the Code tab, use Discard my changes to put the file back.

Visitors are not affected

A failed build never reaches your published app. Visitors keep seeing the version you last published.