Skip to content

ryyansafar/MacMonitor

BranchesTags

Repository files navigation

MacMonitor Logo

MacMonitor

The most complete Apple Silicon system monitor that fits in your menu bar.

Real-time CPU, GPU, memory, battery, power rails, fan, network, and disk —
all from native kernel sensors. No third-party tools. No dependencies.


macOS 13+ Apple Silicon Version Swift 5.9 SwiftUI License: MIT


Full dashboard Menu bar indicator Battery section
Full dashboard Menu bar indicator Battery & power

Table of Contents

What's New in v2.0

Full changelog: CHANGELOG.md

Native sensors — zero dependencies

MacMonitor 2.0 reads all hardware data directly from Apple's kernel interfaces. No mactop, no Homebrew tools, no external binaries — just the same SMC and IOReport APIs that Activity Monitor and TG Pro use under the hood.

v1.x v2.0
GPU, temps, and power required mactop (separate install) All sensors read natively via IOReport + SMC
First launch showed "install mactop" banner Ships fully featured out of the box
Chip displayed as "Apple M2" Displays clean variant: M2, M2 Pro, M2 Max, M2 Ultra
No CPU die hotspot Shows both avg temp and die hotspot (TCMz)
No fan support Fan RPM shown automatically (hidden on fanless models)

New sensor data in this release

  • CPU Die Hotspot — the absolute peak temperature on the CPU die (SMC key TCMz), not just an average. This is the same reading TG Pro labels "CPU Die (Hotspot)".
  • Fan RPM — live fan speed via SMC key F0Ac. Section is hidden automatically on fanless models (MacBook Air).
  • Chip variant — accurately identified from machdep.cpu.brand_string and displayed as "M2 Pro", "M2 Max", etc.
  • Sensor research toolkit — sensor-research/ directory includes standalone SMC/HID/IOReport scanners used to discover and verify every sensor key.

Features

Menu bar indicator

Updates every 2 seconds. One glance tells you if everything is fine.

● CPU 12%  MEM 47%    →  green dot  — all clear
● CPU 62%  MEM 71%    →  yellow dot — moderate load
● CPU 91%  MEM 87%    →  red dot    — heavy load, open dashboard

Full dashboard (click to open)

Section What you see
Header Chip variant · thermal state · total system power
CPU Overall · E-cluster · P-cluster · S-cluster (M5+) · per-core bars · avg temp · die hotspot · CPU power
GPU Usage bar · frequency · temperature · GPU power
Fan Live RPM — hidden automatically on fanless models
Memory Used / total · DRAM bandwidth (read + write GB/s) · swap
Battery Charge % · status · charge rate · adapter watts · cycles · health · mAh · cell temp
Network Download / upload (auto-scaled B / KB / MB per second)
Disk I/O Read / write throughput (auto-scaled)
Power rails CPU · GPU · ANE · DRAM · System (PSTR) · Total
Processes Top 8 CPU consumers — name, CPU %, memory
Optimize Purge disk cache + quit heavy apps

Desktop widget

Runs completely standalone — no background process required.

  • Small — CPU, GPU, Memory bars + temperatures
  • Medium — All bars + network speed + power draw

Works on macOS Sonoma and Sequoia desktop, Notification Centre, and Stage Manager.

What is Apple SMC?

The System Management Controller (SMC) is a dedicated co-processor embedded in every Apple Mac. It runs independently of the main CPU and is responsible for managing the hardware at a low level — things the operating system itself doesn't directly control.

On Apple Silicon Macs, the SMC handles:

  • Thermal management — monitoring hundreds of temperature sensors across the CPU, GPU, battery, VRM, SSD, and chassis, and throttling performance to stay within safe limits
  • Power delivery — managing voltage rails, measuring current draw, and controlling how much power each component receives
  • Fan control — on Macs with fans, the SMC decides fan speed based on thermal sensor readings
  • Battery management — tracking cycle count, health, charge rate, and cell temperature
  • Sleep and wake — handling lid close, power button presses, and low-battery shutdown

MacMonitor reads the SMC directly through Apple's private IOKit interface (IOServiceOpen("AppleSMC")). Each sensor has a 4-character key (e.g. TCMz for CPU die hotspot, PSTR for total board power, F0Ac for fan speed) and returns a floating-point value in the relevant unit (°C, Watts, RPM, Amps, Volts).

This is the same data that TG Pro, iStatMenus, and macOS's own thermal management subsystem read. MacMonitor exposes it directly in your menu bar.

For the complete list of SMC keys MacMonitor uses, see SENSORS.md.

Data Sources

MacMonitor pulls from four native macOS kernel interfaces — no third-party tools required:

Source Data Requires privileged helper?
Mach kernel — host_processor_info CPU per-core usage, E/P cluster split No
Mach kernel — vm_statistics64 Memory used/free/compressed, swap No
IOReport + SMC + IOHIDEventSystem GPU%, freq, CPU/GPU temps, die hotspot, fan RPM, ANE/DRAM/GPU power, DRAM bandwidth Yes (one-time setup)
IOKit — pmset / ioreg Battery %, cycles, health, charge rate, adapter watts, cell temp No

The privileged helper (macmonitor-helper) is a small compiled binary installed to /Users/Shared/MacMonitor/. It runs as root to access IOReport, which requires elevated privileges to sample power data. MacMonitor asks for admin approval once on first launch and never again.

Installation

Option A — Homebrew (recommended)

brew tap ryyansafar/macmonitor https://github.com/ryyansafar/MacMonitor
brew install --cask macmonitor

MacMonitor appears in your menu bar immediately.

Auto-update:

brew upgrade --cask macmonitor

Option B — One-line installer

curl -fsSL https://raw.githubusercontent.com/ryyansafar/MacMonitor/main/install.sh | bash

Downloads the latest DMG, removes the quarantine flag, installs the privileged helper, and launches MacMonitor.

Option C — Manual DMG

  1. Download MacMonitor.dmg from Releases
  2. Open the DMG and drag MacMonitor to Applications
  3. Double-click Install.command inside the DMG to clear the quarantine flag (or run xattr -dr com.apple.quarantine /Applications/Macmonitor.app in Terminal)
  4. Launch MacMonitor from Applications or Spotlight

macOS may block the first launch because MacMonitor isn't notarised (no paid Apple Developer account needed to build or distribute it). The Install.command script handles this automatically. After the first approved launch, macOS never asks again.

Building from Source

Requirements:

  • Xcode 15+
  • Apple Silicon Mac
  • macOS 13 Ventura+
# Clone
git clone https://github.com/ryyansafar/MacMonitor.git
cd MacMonitor

# Open in Xcode
open Macmonitor.xcodeproj

In Xcode: select the Macmonitor target → Signing & Capabilities → set your Team to your Apple ID (free account works). Do the same for MacMonitorWidget. Press Cmd+R.

Build the privileged helper from the command line:

SDK=$(xcrun --show-sdk-path)

clang -ObjC \
  -o /tmp/macmonitor-helper \
  helper/macmonitor-helper.m \
  Macmonitor/IOReportWrapper.m \
  Macmonitor/SMC.c \
  -I Macmonitor/ \
  -framework Foundation -framework IOKit -framework CoreFoundation \
  -isysroot "$SDK" -L "$SDK/usr/lib" -lIOReport

# Install
mkdir -p /Users/Shared/MacMonitor
cp /tmp/macmonitor-helper /Users/Shared/MacMonitor/macmonitor-helper
chmod 755 /Users/Shared/MacMonitor/macmonitor-helper

How It Works

┌──────────────────────────────────────────────────────────────────────┐
│                           MacMonitor.app                              │
│                                                                        │
│  ┌─────────────┐     ┌────────────────────────────────────────────┐   │
│  │ AppDelegate │     │            SystemStatsModel                 │   │
│  │             │     │                                              │   │
│  │ NSStatusItem│◄────│  CPU    ← host_processor_info() [Mach]      │   │
│  │   (2s tick) │     │  MEM    ← vm_statistics64() [Mach]          │   │
│  │             │     │  NET    ← getifaddrs() delta                 │   │
│  │ NSPopover   │     │  DISK   ← IOKit disk stats delta             │   │
│  │  (SwiftUI)  │     │  GPU/⚡ ← macmonitor-helper (IOReport+SMC)  │   │
│  │             │     │  BAT    ← IOKit / ioreg                      │   │
│  └─────────────┘     └────────────────────────────────────────────┘   │
└──────────────────────────────────────────────────────────────────────┘

          macmonitor-helper (privileged, runs as root)
          ┌────────────────────────────────────────────┐
          │  IOReport  → CPU/GPU power, DRAM bandwidth │
          │  SMC       → temps, fan RPM, total power   │
          │  IOHIDEventSystem → PMU die temperatures   │
          └────────────────────────────────────────────┘

┌──────────────────────────────────────────────────────────────────────┐
│                    MacMonitorWidget extension                          │
│                                                                        │
│  StatsProvider (TimelineProvider)                                      │
│  CPU  ← host_processor_info() [0.8s two-sample delta]                 │
│  MEM  ← vm_statistics64()                                              │
│  Refreshes every 5 seconds — no background process required           │
└──────────────────────────────────────────────────────────────────────┘

Key design decisions:

  • No App Sandbox — required to access Mach kernel APIs and IOReport. This means MacMonitor cannot be submitted to the Mac App Store, but can be freely distributed as a DMG.
  • No third-party dependencies — everything is read from macOS's own kernel interfaces.
  • Privileged helper pattern — IOReport power sampling requires root. A minimal helper binary runs with elevated privileges; the main app communicates with it via stdout JSON. The helper does nothing other than sample sensors and exit.
  • Two-sample delta — CPU usage, DRAM bandwidth, and power are all rate metrics. MacMonitor takes two samples 100ms apart and computes the delta, giving accurate per-second rates.

Sensor Reference

See SENSORS.md for the complete map of every hardware sensor used:

  • All SMC temperature keys (TCMz, TRDX, TPMP, T5SP, TB0T, …)
  • IOReport channels (Energy Model, CPU Stats, GPU Stats, AMC Stats)
  • HID PMU die temperature sensors
  • Fan speed keys (F0Ac, F1Ac)
  • Battery and power rail keys
  • Accuracy cross-validation table vs mactop

Contributing

Contributions are welcome. MacMonitor is intentionally small and dependency-light — the goal is to stay close to the metal.

Quick start:

git clone https://github.com/ryyansafar/MacMonitor.git
cd MacMonitor
open Macmonitor.xcodeproj

See CONTRIBUTING.md for:

  • Full development setup
  • Architecture overview
  • Code style guide
  • Sensor contribution guide (adding support for new Mac models)
  • PR checklist and review process

Good first issues:

  • Add a second fan row for dual-fan Macs (Mac Pro, MacBook Pro 16")
  • Configurable refresh interval in Settings
  • Display memory pressure level from HOST_VM_INFO64
  • Add global keyboard shortcut to open/close the popover
  • Validate sensor keys on M3 / M4 / M3 Pro / M4 Max hardware

Hardware Tested

Model Chip Fan Status
MacBook Air (M2, 2022) M2 No (passive) ✅ Fully verified

Help expand this table. Run the scanners in sensor-research/ on your Mac and open a PR — see CONTRIBUTING.md.

Roadmap

  • M3 / M4 / M5 sensor key validation
  • Dual-fan support (Mac Pro, MacBook Pro 16")
  • Per-core temperature display
  • Configurable refresh rate
  • Global keyboard shortcut
  • Disk space section
  • iCloud / Time Machine integration
  • Sparkle auto-updater (signed binary)

Support

If MacMonitor is useful to you:

Platform Link
Portfolio ryyansafar.site
GitHub github.com/ryyansafar
Buy Me a Coffee buymeacoffee.com/ryyansafar
PayPal paypal.me/ryyansafar
Razorpay razorpay.me/@ryyansafar

Starring the repo also helps a lot — it makes MacMonitor easier to find.

Acknowledgements

  • Apple's IOReport, SMC (AppleSMC), and IOHIDEventSystem — the native kernel interfaces that power all sensor data in this app
  • Apple's Mach kernel (host_processor_info, vm_statistics64) — for dependency-free CPU and memory sampling
  • mactop by @metaspartan — used as an independent cross-validation reference during sensor research for v2.0

License

MIT — Copyright © 2025–2026 MacMonitor Contributors.

Free to use, modify, fork, and distribute. Attribution appreciated but not required.

Built for Apple Silicon. Reads from the metal.

About

Real-time Apple Silicon system monitor — menu bar app + desktop widget for macOS

github.com/ryyansafar/MacMonitor

Topics

macos swift homebrew m2 system-monitor widgetkit m1 menu-bar swiftui apple-silicon

Resources

Readme

License

MIT license

Contributing

Contributing
Activity

Stars

37 stars

Watchers

0 watching

Forks

1 fork
Report repository

Releases 8

MacMonitor v2.0.0 Latest
Apr 6, 2026
+ 7 releases

Packages

 
 
 

Contributors

Languages