written by Claude Opus 4.6 via Claude Code
Inspired by Simon Willison's Vibe coding SwiftUI apps is a lot of fun
Real-time power monitor for Apple Silicon Macs. Native SwiftUI app that shows exactly where your watts are going — from the SoC components down to individual apps.
brew install --cask abizer/tap/wtopThe cask downloads a pre-built .app, installs it to /Applications, strips the quarantine attribute, and sets up the privileged helper daemon (prompts for your password once).
- System power — total draw, battery discharge rate, adapter input
- SoC breakdown — CPU, GPU, ANE, DRAM power via IOReport
- Per-process energy — actual watts per app, not just CPU time
- CPU cores — per-core utilization for E-cluster and P-cluster
- Temperatures — CPU, SSD, battery via SMC sensors
- App grouping — Brave's 12 helper processes collapse into one row
- Power history — 5-minute sparkline of system power
- Thermal state — nominal/fair/serious/critical indicator
- Battery projection — estimated time remaining at current draw
The app works without the privileged helper — system power, CPU/GPU/ANE/DRAM breakdown, core utilization, temperatures, and user-app energy are all available. The helper adds full visibility into system daemons (WindowServer, kernel_task, launchd, etc.) including their CPU time and energy consumption.
- All / Apps / System — filter by user apps or system daemons
- Sort — by Power, CPU, Memory, or Name
- Search — filter processes by name
- Refresh — 0.5s, 1s, 2s, or 5s intervals
wtop reads from five macOS subsystems, none of which require third-party dependencies:
| What | How |
|---|---|
| System power | IOKit AppleSmartBattery registry |
| CPU/GPU/ANE/DRAM | IOReport Energy Model channels via /usr/lib/libIOReport.dylib |
| Per-process energy | proc_pid_rusage with rusage_info_v6.ri_energy_nj |
| CPU core load | Mach host_processor_info |
| Temperatures | SMC keys via IOKit (sp78 fixed-point) |
The privileged helper runs on-demand — launchd starts it when the app opens an XPC connection, and it exits 30 seconds after the app closes. It never runs in the background.
Sources/
App/ SwiftUI app (runs as user)
Helper/ Privileged daemon (root, on-demand via launchd + XPC)
Shared/ XPC protocol definition
Without root, proc_pidinfo can't see system processes. The helper provides full process data for all PIDs over XPC when installed. Without it, user apps are still fully visible.
This builds from source, installs the app to ~/Applications (Spotlight-searchable), and sets up a privileged helper daemon for full system process energy data.
git clone https://github.com/abizer/wtop
cd wtop
just install # .app → ~/Applications
just install-helper # privileged daemon (needs sudo)Requires Swift 5.9+ and macOS 14+.
brew uninstall --cask wtopThe cask's uninstall block handles launchctl cleanup and helper removal automatically.
If installed from source:
just uninstall- Apple Silicon Mac (M1/M2/M3/M4)
- macOS 14 Sonoma or later
- Swift 5.9+ (for building from source)
MIT
Built with insights from mactop, macmon, and the Stats app's SMC implementation.