iNetspeed

A lightweight native macOS menu bar app that monitors network speed in real time.

Features

Menu bar display

• Live download and upload speed, updated every second
• Compact unit formatting (B, K, M, G) that fits the status bar

Summary panel

• Current download and upload speed with color-coded labels
• 30-minute speed history chart with smooth bezier curves
• Interactive chart — hover to see exact speeds at any point in time
• Subtle gridlines and time axis labels

Per-app traffic

• Top 6 apps by current network usage
• App icons with a gear fallback for system processes
• Proportional traffic volume bar per row using the system accent color
• Processes with no current traffic stay visible, dimmed, until evicted
• Chromium-style multi-process apps and apps with multiple independent root processes (e.g. Dropbox) are grouped into a single row

Requirements

• macOS 14 or newer
• Xcode command line tools or Xcode (for Swift Package Manager)

Run

swift run iNetspeed

Build

Release binary:

swift build -c release

Launchable .app bundle:

sh scripts/build-app.sh
open .build/iNetspeed.app

The app runs as an accessory and appears only in the menu bar — no Dock icon.

Implementation notes

• Network interface speeds are read directly from kernel counters via getifaddrs — no polling overhead
• Per-app traffic uses nettop -x -n -L 1 -P on a background thread with backpressure to avoid blocking the main actor
• Process grouping walks the OS process tree via sysctl(KERN_PROC_PID) to find the root app for each nettop entry, then does a secondary merge by resolved app name to handle apps with multiple independent root processes
• Root PID and app name lookups are cached per nettop key and pruned each sample cycle to prevent stale PID reuse
• All views update in-place while the menu is open — no teardown and rebuild on each tick