Open-source system monitor for macOS. Lives in the menu bar.
Activity Monitor is heavy and buried in /Applications/Utilities; iStat Menus is great but paid. MacStats sits in the middle: CPU, RAM, disk, network, battery and the top processes at a glance, straight from the menu bar.
- Menu bar — pick any of CPU %, temperature, RAM, disk I/O and network rate. Each one is its own status item, so macOS hides them one by one when the bar gets crowded. Prefer a clean bar? Turn on the plain app icon and drop every metric.
- Dropdown — live readouts per domain plus the top processes by CPU / RAM / Disk / Network / Energy. Clicking an icon opens the list already on that metric's tab.
- Main window — Overview, CPU, GPU, Memory, Disk, Network, Battery, Temperature, Fans and a filterable process table, each chart with a
1m / 1h / 24hswitcher. - Cheap when idle — the expensive probes (process list, battery, volume capacity, temperature, GPU, fans, Wi-Fi,
nettop) only run while some view needs them. Idle sits around 76 MB and ~0.5 % CPU. - Settings — last tab in the main window sidebar: what shows in the menu bar, and whether MacStats appears in the Dock (off by default).
- Native and offline — Swift 6 + SwiftUI + AppKit, no dependencies, no accounts, no telemetry. The only outbound call is the public-IP lookup in the Wi-Fi pane.
Download the .dmg from Releases and drag MacStats to /Applications.
The build isn't signed with an Apple Developer ID, so Gatekeeper blocks the first launch. Right-click the app → Open → Open, or allow it in System Settings → Privacy & Security.
Requires macOS 13+ on Apple Silicon.
./Scripts/run.sh # debug build + launch
./Scripts/bundle.sh release # production .app under .build/Needs the Swift 6.3 toolchain (Xcode 15+). No package dependencies.
Click any menu bar item to open the dropdown. The checkboxes at the bottom choose which metrics show in the bar (persisted across restarts). The window icon in the header opens the main window; ⌘Q quits. There's no settings window, on purpose.
- No SMC voltage / current sensors — the keys vary per chip family. Fan RPM does work.
- Wi-Fi SSID needs Location permission on macOS 13+; without it the pane shows "Connected" but no name.
- Not signed or notarized yet, hence the Gatekeeper override above.
- Apple Silicon only. On Intel the temperature, GPU and fan panes hide themselves.
Issues and PRs welcome, but this is meant to stay small. Before opening one: swift build -c release passes and ./Scripts/run.sh launches cleanly. No tests, manual verification is the bar.
Architecture notes, the sampling design and the tricky Darwin APIs live in CLAUDE.md (mirrored at AGENTS.md).
Icon hand-authored in design_handoff_macstats_logo/. Inspired by iStat Menus.
MIT. See LICENSE.