Xcode, Docker, node_modules: cleaning developer files on Mac

Measure before you delete

Open Terminal and check the usual suspects. Each line prints a size, or nothing if the folder doesn't exist:

du -sh ~/Library/Developer/Xcode/DerivedData
du -sh ~/Library/Developer/CoreSimulator
du -sh ~/.npm ~/Library/Caches/Homebrew ~/.ollama
docker system df

Write the numbers down. It keeps the clean-up focused on what is actually big on your Mac.

Xcode

• DerivedData (~/Library/Developer/Xcode/DerivedData): build products and indexes. Everything in it is safe to delete; the next build takes longer because Xcode starts from scratch. You can remove one project's folder instead of all of it.
• Unavailable simulators: run xcrun simctl delete unavailable to remove simulators for runtimes you no longer have.
• iOS DeviceSupport (~/Library/Developer/Xcode/iOS DeviceSupport): debug symbols for each iPhone or iOS version you have connected. Old versions can go, but Xcode copies them again only from a device still running that version, and you need them to read crash reports from it.
• Archives (~/Library/Developer/Xcode/Archives): see What to keep.

Docker

docker system df shows how much space images, containers, volumes and build cache use. Then:

• docker system prune removes stopped containers, networks not used by any container, dangling images and unused build cache.
• Add -a to also remove every image not used by a container. You will download them again next time.
• Volumes are kept unless you add --volumes. Volumes often hold database data, so check before you add it.

node_modules and npm

• node_modules in projects you no longer work on can be deleted. npm install brings them back from package.json and the lock file.
• The npm cache lives in ~/.npm. npm's own docs say clearing it is usually unnecessary because the cache is self-healing, which is why npm cache clean --force needs the force flag. Clear it only to get the space back.

Homebrew and pip

• Homebrew removes old versions when you upgrade and runs extra cleanup every 30 days. Its download cache is usually ~/Library/Caches/Homebrew; brew cleanup clears what it no longer needs.
• pip: pip cache dir shows where the cache is and pip cache purge removes everything in it.

Local AI models

• Ollama keeps models in ~/.ollama/models. Run ollama list, then ollama rm model-name for the ones you don't use.
• Hugging Face downloads go to ~/.cache/huggingface.

A single model can be several gigabytes, so on an AI workstation this is often the biggest single win.

What to keep

• Xcode archives of builds you shipped. They are what you need to read crash reports from that version. Delete only archives of builds you never released.
• Docker volumes with data you care about.
• Anything you can't rebuild: local databases, generated datasets, model fine-tunes.

Where Tidymint helps

Tidymint is a free, open-source Mac cleaner. For developers it:

• lists the npm cache and your user caches (including Homebrew and pip) in Clean Now, grouped and explained before you press Clean;
• clears _to_delete and _tmp folders inside the project folders you add in Settings;
• shows plain notes in Space Lens for folders like DerivedData, CoreSimulator, node_modules, iOS DeviceSupport, .ollama and Hugging Face, so you know what a big bubble is before you act;
• checks your project folders before removing duplicate files a script still uses.

It does not run docker or xcrun commands for you. Everything you select always goes to the Trash first.