Route links by the app you click them in

Junction is a free, open-source macOS app that becomes your default browser and routes each link by your rules. A rule can match the app the click came from, so every link out of Slack, your terminal, or Mail can go somewhere different.

How do I open every link from Slack in a different browser?

Write a rule with sourceApps set to Slack’s bundle ID. Any link clicked in Slack then follows that rule, whatever site it points to.

{
  "name": "From Slack → work profile",
  "match": { "sourceApps": ["com.tinyspeck.slackmacgap"] },
  "action": { "app": "com.google.Chrome", "profile": "Profile 1" }
}

$ junction test "https://example.com/quarterly-report" --source com.tinyspeck.slackmacgap
input:       https://example.com/quarterly-report
source:      com.tinyspeck.slackmacgap
rule:        [1] From Slack → work profile
action:      open in com.google.Chrome profile "Profile 1"
url:         https://example.com/quarterly-report

Keep it near the top of your list. Rules run top to bottom and the first match wins, so a site rule above it would catch some of Slack’s links first.

How do I find an app’s bundle ID?

Ask macOS for it in Terminal:

$ osascript -e 'id of app "Slack"'
com.tinyspeck.slackmacgap

Can terminal links open in my dev browser?

Yes. List both terminals in sourceApps, and the URLs printed by your dev server, gh, or a failing build open in the browser you develop in.

{
  "name": "From the terminal → Chrome",
  "match": { "sourceApps": ["com.googlecode.iterm2", "com.apple.Terminal"] },
  "action": { "app": "com.google.Chrome" }
}

More rules for developers are in routing localhost and dev links.

Can a rule match both the app and the site?

Yes. When a rule has both sourceApps and patterns, a link has to match both. That narrows a rule to one app’s links for one site.

{
  "name": "Jira from Slack → work profile",
  "match": { "patterns": ["*.atlassian.net/*"], "sourceApps": ["com.tinyspeck.slackmacgap"] },
  "action": { "app": "com.google.Chrome", "profile": "Profile 1" }
}

Can links from Mail be copied instead of opened?

Yes. Give the rule the clipboard action and a click in Mail copies the link rather than opening it, so you can read the whole address first. Put this rule at the top of your list: any rule above it would still open the link. More on that in link privacy.

{
  "name": "From Mail → clipboard",
  "match": { "sourceApps": ["com.apple.mail"] },
  "action": { "clipboard": true }
}

How do I test a source-app rule without that app?

Run junction test with --source and the app’s bundle ID. It prints which rule wins and why, and opens nothing.

Get Junction

Junction is free and MIT-licensed, for macOS 13 or later on Apple silicon and Intel. Install it with Homebrew or the DMG, then follow the first-launch steps.