BrowserProxy

A lightweight macOS app that acts as your default browser and routes URLs to Chrome or Firefox based on configurable rules. For example, open all links from Slack in Firefox while everything else goes to Chrome.

BrowserProxy runs as a background process with no dock icon and near-zero resource usage.

Features

• Route URLs to different browsers based on which app sent the link
• Match by app name or bundle ID
• Hold Option while clicking a link to manually pick a browser
• JSON config — edit and changes apply instantly (no restart needed)
• Logs every URL event for debugging

Requirements

• macOS 13+ (tested on macOS 15 Sequoia)
• Go 1.21+ (for building from source)
• Homebrew (to install the defaultbrowser helper)

Install

git clone https://github.com/david-erel/browser-proxy.git
cd browser-proxy
./scripts/install.sh

The installer will:

1. Install the defaultbrowser helper via Homebrew (if needed)
2. Build the app
3. Copy it to /Applications
4. Launch it
5. Set it as your default browser (macOS will ask you to confirm)
6. Add it to Login Items so it starts on boot

That's it. You're done.

Configuration

Edit ~/.config/browser-proxy/config.json:

{
  "defaultBrowser": "chrome",
  "rules": [
    {
      "senderName": "Slack",
      "browser": "firefox"
    },
    {
      "senderBundleId": "com.tinyspeck.slackmacgap",
      "browser": "firefox"
    }
  ]
}

Field	Description
defaultBrowser	"chrome" or "firefox" — used when no rule matches
rules	Array of routing rules (first match wins)
rules[].senderName	Match by sending app's display name (case-insensitive)
rules[].senderBundleId	Match by sending app's bundle ID (case-insensitive)
rules[].browser	"chrome" or "firefox"
logFile	Optional — defaults to ~/Library/Logs/browser-proxy/url.log

Changes take effect immediately, no restart required.

Manual Browser Selection

Hold the Option key while clicking any link to get a dialog letting you choose Chrome or Firefox for that specific URL.

Logs

Every URL event is logged as JSONL to ~/Library/Logs/browser-proxy/url.log:

{"timestamp":"2026-02-18T10:30:00Z","url":"https://example.com","senderBundleId":"com.tinyspeck.slackmacgap","senderName":"Slack","chosenBrowser":"firefox","wasManualChoice":false}

Uninstall

./scripts/uninstall.sh

This stops the app, removes it from Login Items and /Applications, and optionally cleans up config and log files. Afterwards, set another browser as your default in System Settings > Desktop & Dock > Default web browser.

Building Manually

If you prefer not to use the installer:

make build        # Build the .app bundle
make install      # Copy to /Applications and register
make set-default  # Set as default browser
make login-item   # Auto-start on login
make restart      # Rebuild, install, and relaunch
make clean        # Remove build artifacts
make uninstall    # Remove from /Applications

How It Works

BrowserProxy registers itself as a macOS URL handler for http and https schemes. When any app opens a URL, macOS routes it to BrowserProxy, which:

1. Reads the config file
2. Identifies the sending app
3. Matches against the rules (first match wins, falls back to defaultBrowser)
4. Opens the URL in the chosen browser

The app is built with Go and Objective-C (Cocoa) to integrate with macOS native URL handling and LaunchServices.

License

MIT