Boost is a menu bar app that shows what your memory is actually doing, then gives back only what is genuinely idle. No fake numbers. No subscription. No network access.
GPL-3.0 · Apple Silicon + Intel · free
What the readout means
Using the most memory
No app closing. No admin password.
macOS fills spare RAM with cache on purpose. It is the fastest thing your Mac can do with memory it isn't using, and it yields the moment an app asks for it. Counting it as “used” makes the problem look bigger than it is.
Cached memory is available memory. Files kept in RAM because nothing else needed it. The instant an app asks, macOS hands it over. A big cache is a Mac using spare memory well, not a Mac that is full.
How a cleaner reads it
Big warning number. “Clean 3.75 GB.” It would shrink memory macOS is using well, and leave the Mac slower.
What is actually true
3.75 GB of that is cache, handed back the instant an app asks. 4.89 GB available without closing anything.
A high cache is a healthy Mac. Not a full one.
One window, no dashboard theatre. Every app and its helpers become a single row with a real total, not thirty mystery processes. The popover above is the short version.
Quitting throws away where you were. Pause freezes the app and every helper: no CPU, no state lost, and macOS is free to move its pages to disk. Switch back and it resumes exactly where it was.
Pause freezes the app and its helpers. Resume puts everything back where it was.
Boost scans a short allowlist. A folder is listed only when the manifest next to it proves what it is, and nothing is ticked for you. Removing files should be a decision, not a default.
Never scanned
If proving it is safe would need a permission prompt, Boost skips it instead of asking.
The second check
First, the path must be on the allowlist. Then Boost resolves the real path and checks it again immediately before removal.
A symlink sitting in a cache and pointing at your Documents is how tools like this destroy data. There is a test that builds exactly that trap.
One reading a minute, kept for seven days. Peak, average, and how often your Mac went into swap, so “was it slow at 3pm yesterday” has an answer instead of a guess.
Reading every minute
Recorded on your Mac and nowhere else. Alerts ignore spikes that pass on their own.
Swap > 1 / 2 / 4 GB
It tells you when swap crosses the threshold you chose, not every time the number moves.
One full minute
A spike that passes on its own is ignored. A minute of tight memory gets a notification naming the app using the most.
Pause, never close
It can pause apps you ticked. It cannot close them. There is a test for that, because it matters.
Projects, large files, local AI models, uninstall, and a report you can paste into a bug thread. All of it follows the same rule: show the evidence before offering the action.
Finds node_modules, Rust target, SwiftPM .build, Python virtualenvs and CocoaPods in projects you haven't touched for 30 to 180 days. A folder is listed only when the manifest next to it proves what it is. Everything goes to the Trash.
TrashThe biggest single files in Downloads, Desktop, Documents, Movies, Music and Pictures, with how long since you opened each. Scans only when you press Scan. Files only, never folders, app bundles or photo libraries.
TrashThe models Ollama, Hugging Face and LM Studio downloaded, with sizes and when each was last used. Ollama models share files, so each size is what removing that one frees. Each model is checked again just before it moves, and nothing moves while an Ollama download is running. Reads names, sizes and dates only.
TrashPick an app or drop one onto the window. Leftovers appear with sizes before anything moves. Only exact matches. Everything goes to the Trash, and there is an Undo.
UndoA plain-text summary for a bug report: your Mac, pressure, swap, the biggest apps and the last day's peak. App names and sizes only. No file paths. No username. Nothing sent anywhere.
LocalStart at login. Dock badge. ⌥⌘B. Sort by memory or CPU. Reveal in Finder. Light and dark, and Liquid Glass on macOS 26. The shortcut is off by default, because claiming a system shortcut is not something an app should help itself to.
NativeThe same job without a window: close, pause, resume, dry-run. Pins are written to a file the script and the app both read, so a hotkey and the menu bar agree.
CLI$ ./boost.sh# close apps and helpers$ ./boost.sh --pause# freeze them instead$ ./boost.sh --resume# unfreeze everything, system-wide$ ./boost.sh --dry-run# show what it would touch, change nothing
Homebrew clears the quarantine flag for you. Building from source never sets one, and needs only the Command Line Tools, not Xcode.
On signing, plainly
Boost is signed with a local certificate, not notarized. Notarizing needs a paid Apple Developer account, which a free app does not have. The Homebrew cask clears the quarantine flag. A source build never sets one. Read the full note.
macOS 14+ · Apple Silicon + Intel · one universal binary · GPL-3.0
$ brew install --cask kernel-hunter/boost/boost
| What | Why | When |
|---|---|---|
| None | Reading the process table and memory stats; signalling your own apps. | Always |
| Accessibility | Counting an app's open windows for “close button quits the app”. | Only if you enable it |
| Notifications | The swap and pressure alerts. | Only if you turn them on |
| Login item | Starting Boost at login. | Only if you turn it on |
| Admin password | The optional /usr/sbin/purge disk cache. | Only if you enable purge |