Yes. ~/Library/Developer/Xcode/DerivedData holds build output: compiled files, indexes and
intermediate products. Xcode recreates everything in it the next time you build or open a
project.
What you lose
Time, not data. The first build of each project after deleting DerivedData is a clean build, and Xcode re-indexes the project, so search and autocomplete are slower for a few minutes.
When it is worth it
- When it has grown large, which is common after months of work on several projects.
- When a project builds with strange errors that a clean build fixes.
- For projects you no longer work on, whose build output is pure waste.
How
Quit Xcode, then move the DerivedData folder, or just the folders of old projects inside it,
to the Trash. Empty the Trash when you are sure your projects still build.
