Mac storage basics · Developer tools
Can I keep my code projects and developer caches on an external drive?
Short answer: Yes — keep projects on a fast external SSD and point tools like Xcode's DerivedData location at it. Use APFS, and expect builds to stop if the drive disconnects.
Yes, and a fast external SSD works well for it. You can keep project folders there directly, and point some tools at it — Xcode's Settings → Locations lets you choose a custom DerivedData location.
Two cautions: some tools behave oddly on non-APFS formats or on case-sensitive volumes, and builds stop if the drive disconnects. Storage Studio moves big developer caches to an external drive with a link left behind so tools keep using their usual paths — one of the workflows in its manual. See moving folders.