The short answer
Yes. Rebuilt or re-downloaded automatically when needed.
What is it?
DerivedData is where Xcode keeps everything it produces while building: compiled object files, module caches, indexes for code completion and search, build logs and test results. Each project gets its own subfolder named after the project plus a random suffix, and folders for projects you deleted long ago are never cleaned up. On an active developer Mac it typically ranges from a few gigabytes to several tens of gigabytes.
Intermediate build products. Xcode rebuilds them on the next build.
What happens if you delete it?
Xcode recreates the folder the next time you open or build a project. The first build afterwards is a full, slower build and indexing restarts in the background; no source code or settings are lost.
How to remove it properly
Quit Xcode, then move ~/Library/Developer/Xcode/DerivedData (or only the subfolders of projects you no longer work on) to the Trash using Finder’s Go › Go to Folder…. Xcode › Settings › Locations shows the current DerivedData location and has an arrow button that opens it in Finder.
Quit the app that uses it, then move it to the Trash. Empty the Trash when you’re sure.
Before you delete it
Avoid deleting it in the middle of a build or test run, and expect the next build to take longer on large projects.
How MoreRoom helps
MoreRoom recognises this item, shows its real size and when it was last used, and labels it “Safe to remove”. In the free version you can move it to the Trash in one click, with Undo; Pro collects every safe item at once.
Frequently asked questions
Is it safe to delete Xcode DerivedData on Mac?
Yes. Rebuilt or re-downloaded automatically when needed. Xcode recreates the folder the next time you open or build a project. The first build afterwards is a full, slower build and indexing restarts in the background; no source code or settings are lost.
Will Xcode build data (DerivedData) come back after I delete it?
Yes. Xcode recreates the folder the next time you open or build a project. The first build afterwards is a full, slower build and indexing restarts in the background; no source code or settings are lost.
How do I remove Xcode build data (DerivedData) properly?
Quit Xcode, then move ~/Library/Developer/Xcode/DerivedData (or only the subfolders of projects you no longer work on) to the Trash using Finder’s Go › Go to Folder…. Xcode › Settings › Locations shows the current DerivedData location and has an arrow button that opens it in Finder.