Port Monitor

A small macOS menu bar app that shows which local ports are listening, which process owns them, and lets you kill that process without leaving the menu bar.

Download · What it does · Build from source · Usage

Port Monitor is for the familiar "what is using this port?" moment. Click the menu bar icon, see the current TCP listeners, and stop the one you do not need anymore.

• Shows active listening TCP ports
• Lists the process name and PID for each port
• Lets you kill a process right from the menu
• Runs as a menu-bar-only app, so it stays out of the Dock
• Ships as a universal build for Apple Silicon and Intel Macs

1. Open the releases page.
2. Download PortMonitor.dmg from the release assets.
3. Open the DMG and drag Port Monitor into Applications.
4. Launch the app from Applications.

• macOS 26+
• Xcode 26 or Apple developer tools with Swift 6.2+
• iconutil (included with macOS)

# Run tests
swift test --build-path /tmp/portmonitor-spm --disable-experimental-prebuilts -j 2

# Build the app bundle
./scripts/build.sh

# Package a DMG
./scripts/create-dmg.sh

Artifacts end up in build/:

• build/PortMonitor.app
• build/PortMonitor.dmg

• Pushes to main and pull requests to main run CI, test the app, build the app bundle, package the DMG, and upload both as workflow artifacts.
• Pushing a version tag like v1.0.1 publishes a GitHub release and attaches PortMonitor.dmg automatically.

Port Monitor uses lsof -nP -iTCP -sTCP:LISTEN -FpcnT to find local listening TCP ports. It parses that output, turns it into app models, and shows the results in a menu bar UI. From there you can refresh the list, see which process owns a port, and kill it when you need to free something up.

1. Launch Port Monitor.
2. Click the menu bar icon.
3. Review the current listening ports.
4. Click Kill next to a process you want to stop.
5. Use the power button to quit the app.

PortMonitor/
├── PortMonitor/              # App entry point, UI, services, models
├── Tests/PortMonitorTests/   # Parsing, command runner, view model tests
├── scripts/                  # Build, packaging, and icon tooling
├── assets/                   # Source artwork for app and menu bar icons
├── Package.swift             # Swift Package Manager setup
└── project.yml               # XcodeGen project definition

• PortMonitor.xcodeproj is generated from project.yml with XcodeGen. Run xcodegen after changing project.yml; tests and release builds use SwiftPM (swift test, scripts/build.sh) and do not need the Xcode project.
• The app is a menu-bar-only macOS app via LSUIElement.
• CI validates pushes and pull requests, and release automation publishes a DMG from GitHub Actions when a v* tag is pushed.
• The packaged app is built as a universal binary for Apple Silicon and Intel Macs.

MIT License