Mopup › For developers Build tools cache everything. Coding agents start dev servers and leave git worktrees behind. AI apps keep crash reports, virtual machines and database backups. Docker keeps growing. Mopup finds all of it on your Mac, says what each item is, and removes only what your tools can rebuild or what you pick.
Build caches, each with what removing it means #
Xcode's DerivedData, device support files, simulators and SwiftUI previews. Gradle caches, Android Studio caches and emulators. npm and Yarn caches, Puppeteer and Playwright browsers, and Node build caches. Old Flutter SDKs and the Pub cache, Homebrew downloads, JetBrains IDE caches, and the pip, Go and Cargo caches. Anything you might want back, like Xcode archives or an emulator, is marked Your call and left unticked. The Storage section adds up all Xcode keeps, simulator runtimes included, and says where to remove the runtimes you no longer test on.
Old projects and merged worktrees #
The Projects section looks through the folders you keep code in for generated folders: node_modules, .next, .turbo, Pods, target, .build, .gradle, .venv and more. It ticks them in projects you haven't touched for 30 days, except Python environments, which are your call. bun and pnpm share files between projects, so Mopup counts shared files once and shows what deleting really frees.
It also finds git worktrees you're done with. A worktree counts as finished when its branch is merged, or its pull
request merged on GitHub (asked through your `gh` command, so squash merges count), and it holds nothing but
generated files. Removal runs `git worktree remove`, never `--force`: anything uncommitted stops it, and
the branch and its commits stay.
What AI apps leave behind #
Cleanup also finds what AI apps leave in your Library:
- Codex crash reports. Some versions of the Codex app saved crash reports and never sent them, thousands a day. They're safe to clear.
- Claude's Cowork virtual machine. The virtual machine Claude's Cowork feature runs in, about 10 GB. It's your call, since Claude downloads it again when you next use Cowork.
- Cursor's old database backup. A copy of Cursor's database that Cursor no longer updates. Your current chats aren't in it.
Claude's and Cursor's files are cleaned only once you've quit the app. Cursor's chat database itself stays, since only Cursor can shrink it without losing your chats. When it passes a gigabyte, Mopup shows how to do that from inside
Cursor. [The guide to coding agents' worktrees](https://mopup.online/guides/coding-agent-worktrees) shows how to clear Codex's
crash reports by hand.
The dev servers nobody stopped #
Activity Monitor shows a dev server as dozens of separate processes. Mopup shows it as one row: the command, the folder it runs in, the ports it listens on, how long it has run and sat idle, and the app it was started from, such as your terminal or editor. Stop it, and everything it started stops too.
- Helpers like workerd and esbuild that kept running after their dev server quit.
- Gradle and Kotlin daemons, language servers, emulators and simulators, with one button for the idle build daemons.
- A notification when a dev server has sat idle for hours, or let Mopup stop idle servers by itself.
Docker, through Docker #
Mopup asks Docker what its build cache, stopped containers, unused images and volumes take, and has Docker do the pruning. Only the build cache is ticked for you. Docker Desktop's memory shows next to your other developer tools, with a Stop button.
Built not to touch your work #
- Source code, git history and documents are never part of a cleanup.
- A worktree with anything uncommitted is never removed.
- Caches and build output are deleted for good, since your tools rebuild them. Files and apps you pick yourself go to the Trash.
- Scanning and cleaning happen on your Mac. Only update checks, asking GitHub which pull requests merged and, with a yearly plan, fetching your renewed license use the network.
The safety page lists every rule Mopup follows before it removes anything.
Pricing #
Free to scan, and your first 2 GB of cleaning is free. Then $9.99 a year, or one payment of $19.99.
Both cover every Mac you own. Team plans cover 5 or 10 people. See [plans](https://mopup.online/#pricing).
Guides for developers #
- How to clean up Claude Code, Cursor and Codex worktrees Where coding agents keep their git worktrees, what they cost in space, and how to remove finished ones safely.
- How to find old coding projects taking up space Find the projects you've stopped working on, see what their dependencies and build folders hold, and clear them safely.
- How to clear Xcode DerivedData and simulators What each Xcode folder holds, which are safe to delete, and the commands that clear them.
- How to free up Docker Desktop disk space See what fills Docker's disk image and reclaim space with Docker's own prune commands.
- How to find and delete old node_modules Find every node_modules folder and its size, remove the ones you don't need, and clear package caches.