TL;DR
MoniMac is a free, open-source system monitor for macOS. It keeps CPU, memory, GPU, network and temperature one glance away in your menu bar, and tells you the moment an app starts dragging your Mac down. It's a native Swift app, under 10 MB, with no account, no analytics and no paid tier.
- 🌐 Website: https://moni-mac.vercel.app/
- 💻 Source: https://github.com/lethanhvietctt5/moni-mac
- ⬇️ Download: https://github.com/lethanhvietctt5/moni-mac/releases/latest/download/MoniMac.dmg
What it does
A menu bar that adapts to you
Each metric (CPU, memory, network, GPU, temperature) can live in the menu bar as its own item, in one of three styles:
- Value only: compact numbers
- Graph only: a 60-second sparkline
- Value + graph: the most information, the most width
When a metric runs hot, its item turns into a warning sign. Hover to see the cause, click to find the app behind it. Hold ⌘ and drag to reorder items, or drag one off the bar to hide it.
One click, the whole picture
Click any item and a popover shows every metric at once, plus the apps working hardest right now. Tabs take you to CPU, memory, GPU, network, disk and battery, with live history, per-core load (P and E cores) and the top apps.
Every number, broken down by app
CPU, memory, GPU, network, disk and power for each app, with helper processes grouped under the app they belong to. That last part matters more than it sounds: a browser or Electron app is dozens of processes, and a flat list hides the real culprit.
Alerts based on patterns, not spikes
A single busy second isn't a problem, so MoniMac waits until a pattern holds:
- CPU: one app stays above your threshold for 2 minutes
- Memory: an app grows fast (+1 GB in 10 minutes may be a leak)
- Disk: sustained heavy writes
- Network: heavy uploads running in the background
And the fix is one click away. The quit sheet lists the app and every helper process with their CPU and memory, then asks apps to quit normally so you can save your work.
Beyond CPU and RAM
- Battery: charge, health, cycle count, live power draw, and which apps drain it
- Bluetooth: AirPods left/right/case, keyboard, trackpad and mouse levels
- Sound: per-app volume, so you can mute the one that keeps chiming
- Temperature & fans: read-only sensor temperatures and fan speeds
For developers: Projects
This one is for the "that dev server from last week is still running" problem. Projects finds every local dev server (Next.js, Vite, Docker, FastAPI and more), groups them by repo, shows port, uptime and memory, flags the ones idle for days, and lets you stop them in one click.
How it compares
| Activity Monitor | iStat Menus | MoniMac | |
|---|---|---|---|
| Live metrics in menu bar | ❌ | ✅ | ✅ |
| Price | Free | Paid | Free |
| Open source | ❌ | ❌ | ✅ |
| History | ❌ | ✅ | ✅ [30 / 90 days, see note] |
| Alerts when an app misbehaves | ❌ | ✅ [verify] | ✅ |
| Local dev server finder | ❌ | ❌ | ✅ |
[Verify the iStat Menus cells before publishing, or delete the table and describe the difference in one paragraph. Stats is another free open-source alternative worth mentioning respectfully.]
Install
Requirements: Apple silicon (M1 or later) and macOS 14.2+. Intel Macs aren't supported.
- Download
MoniMac.dmgfrom Releases. - Drag MoniMac into Applications.
- MoniMac isn't notarized by Apple yet, so macOS blocks it until you remove the quarantine flag. Run this once in Terminal:
xattr -dr com.apple.quarantine /Applications/MoniMac.app
Updates install from inside the app.
Contributing & feedback
MoniMac is at v0.1.1, so it's early and feedback matters. Issues, ideas and PRs are welcome: https://github.com/lethanhvietctt5/moni-mac
What would you want a menu bar monitor to tell you that Activity Monitor doesn't? Let me know in the comments 👇
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