Clean up node_modules, npm caches, Docker and Xcode without breaking your projects

01The rule before any cleanup

A folder such as node_modules or target rebuilds itself, provided it really is the tool’s output and not a folder you worked in. Check that Git ignores it and that your work is saved:

If git check-ignore prints nothing, the folder is not ignored: do not delete it without looking at what it contains.

02JavaScript: node_modules, npm, pnpm, Yarn

To find the heaviest node_modules in a projects folder:

Delete those of inactive projects; an npm install (or pnpm install) rebuilds them. Global caches are cleared with:

03Rust, Python, Java

• Rust: a project’s target folder quickly exceeds several GB. cargo clean deletes it, the next build recreates it.
• Python: a virtual environment (.venv) is rebuilt from requirements.txt or pyproject.toml; pip’s cache is cleared with pip cache purge.
• Java and Android: ~/.gradle/caches and ~/.m2/repository download again on the next build, at the cost of a slower first build.

04Xcode and simulators

~/Library/Developer/Xcode/DerivedData holds intermediate builds: delete its contents with Xcode closed, it is rebuilt on the next build. Simulators for old iOS versions and device symbols are often the largest:

Folders in ~/Library/Developer/Xcode/iOS DeviceSupport for iOS versions you no longer use can go too; they are rebuilt when a device is connected.

05Docker

Start by seeing what takes up space, then clean up step by step:

docker image prune removes unnamed images with no container, docker builder prune the build cache. Avoid docker system prune -a --volumes without thinking: --volumes also erases the data of your local databases.