Keep localhost and dev links in your dev browser

Junction is a free, open-source macOS app that becomes your default browser and routes each link by your rules. Developers use it to keep local servers, preview deployments, and terminal links in one browser, away from the one they read and browse in.

How do I open localhost links in a different browser?

Write a rule with localhost and 127.0.0.1 as bare-host patterns. A bare host matches every path on it, and the port doesn’t stop the match.

rule

{
  "name": "localhost → Canary",
  "match": { "patterns": ["localhost", "127.0.0.1"] },
  "action": { "app": "com.google.Chrome.canary" }
}

junction test

$ junction test "http://localhost:3000/dashboard"
input:       http://localhost:3000/dashboard
rule:        [1] localhost → Canary
action:      open in com.google.Chrome.canary
url:         http://localhost:3000/dashboard

Can preview deployments open next to localhost?

Yes. Match the preview hosts with a subdomain wildcard and send them to the same browser.

rule

{
  "name": "Preview deploys → Canary",
  "match": { "patterns": ["*.vercel.app/*", "*.netlify.app/*"] },
  "action": { "app": "com.google.Chrome.canary" }
}

Can links I click in the terminal open in my dev browser?

Yes, with a rule that matches the terminal app instead of the link — see routing links by app.

How do I open GitHub repo links in GitHub Desktop?

Use the github-desktop deep link, and limit it with a regex to repository home pages. Pull requests, issues, and files keep opening in the browser.

rule

{
  "name": "Repo home → GitHub Desktop",
  "match": { "regex": "^https://github\\.com/[^/]+/[^/?#]+/?$" },
  "action": { "deepLink": "github-desktop" }
}

Patterns only see the host and path; regex matches the full URL, so use it when the shape of the link matters this much.

How do I open vscode.dev links in VS Code?

Use the vscode deep link. A shared vscode.dev or github.dev link then opens in your local editor. This deep link is marked experimental.

rule

{
  "name": "vscode.dev → VS Code",
  "match": { "patterns": ["vscode.dev/*", "github.dev/*"] },
  "action": { "deepLink": "vscode" }
}

junction test

$ junction test "https://vscode.dev/github/jnahian/junction"
input:       https://vscode.dev/github/jnahian/junction
rule:        [1] vscode.dev → VS Code
action:      deep link (vscode)
url:         vscode://github/jnahian/junction

Linear, Figma, and Notion links are in design and project tools.

How do I check a rule before relying on it?

Run junction test with the link. It prints the winning rule and the action without opening anything. junction config validate checks the whole file and explains any problem.

Command	What it does
`junction test <url>`	Shows which rule wins, and why
`junction open <url>`	Routes the link and opens it
`junction config path`	Prints the config file’s path
`junction config validate`	Checks the config file

The config is a plain JSON file at ~/.config/junction/config.json, so you can keep it in your dotfiles — see syncing rules across Macs. When a link goes somewhere unexpected, start with why links open in the wrong browser.

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.