Private Mode

Open links in incognito or private browsing mode automatically based on your routing rules

Default Tamer supports opening URLs in private/incognito mode for most major browsers. This feature works on a per-rule basis, allowing you to automatically open certain links privately while keeping others in normal mode.

How It Works

When you enable “Open in Private Mode” for a rule, Default Tamer passes browser-specific command-line flags to launch the URL in a private window.

Private mode is configured per-rule. You can have some rules open URLs normally while others use private mode, even for the same browser.

Supported Browsers

Default Tamer uses the following command-line flags for each browser:

Chrome

Flag: --incognito

open -a "Google Chrome" --args --incognito "https://example.com"

Opens the URL in Chrome’s incognito mode.

Firefox

Flag: -private-window

open -a "Firefox" --args -private-window "https://example.com"

Opens the URL in Firefox’s private browsing mode.

Edge

Flag: -inprivate

open -a "Microsoft Edge" --args -inprivate "https://example.com"

Opens the URL in Edge’s InPrivate mode.

Brave

Flag: --incognito

open -a "Brave Browser" --args --incognito "https://example.com"

Opens the URL in Brave’s private window.

Opera

Flag: --private

open -a "Opera" --args --private "https://example.com"

Opens the URL in Opera’s private mode.

Vivaldi

Flag: --incognito

open -a "Vivaldi" --args --incognito "https://example.com"

Opens the URL in Vivaldi’s incognito mode.

Browsers Without Command-Line Support

Safari and Arc do not support command-line private mode flags. If you enable private mode for rules targeting these browsers, Default Tamer will open URLs in normal mode instead.

For Safari, private mode requires AppleScript automation, which is not currently supported. Arc does not provide command-line options for private windows.

Fallback Behavior

When a rule specifies private mode:

1. Supported Browser: Default Tamer opens the URL with the appropriate private mode flag
2. Unsupported Browser: The URL opens in normal mode with a debug log message
3. Fallback Browser: If the target browser is unavailable and Default Tamer falls back to another browser, private mode may not work on the fallback

Unknown Browsers

For browsers not explicitly recognized, Default Tamer attempts to use the Chromium-based --incognito flag:

open -a "Unknown Browser" --args --incognito "https://example.com"

This works for most Chromium-based browsers but may fail for browsers built on other engines.

Use Cases

Sensitive Links

Automatically open banking, healthcare, or other sensitive URLs in private mode:

Rule: Domain contains "bank.com" → Chrome (Private Mode)

Social Media Isolation

Browse social media without tracking cookies:

Rule: Domain suffix "twitter.com" → Firefox (Private Mode)
Rule: Domain suffix "facebook.com" → Firefox (Private Mode)

Work/Personal Separation

Keep work-related browsing separate from your personal browsing history:

Rule: From Slack → Chrome (Private Mode)
Rule: From Microsoft Teams → Edge (Private Mode)

Technical Details

Private mode is implemented in BrowserManager.swift:394-418 using the getPrivateModeArguments() method:

private func getPrivateModeArguments(for bundleId: String) -> [String] {
    switch bundleId {
    case BundleIdentifiers.chrome:
        return ["--args", "--incognito"]
    case BundleIdentifiers.firefox:
        return ["--args", "-private-window"]
    case BundleIdentifiers.edge:
        return ["--args", "-inprivate"]
    case BundleIdentifiers.brave:
        return ["--args", "--incognito"]
    case BundleIdentifiers.opera:
        return ["--args", "--private"]
    case BundleIdentifiers.vivaldi:
        return ["--args", "--incognito"]
    case BundleIdentifiers.safari:
        return []
    case BundleIdentifiers.arc:
        return []
    default:
        return ["--args", "--incognito"]
    }
}