Finicky is an MIT-licensed macOS application that registers as your default browser and applies rules written in JavaScript or TypeScript to decide which browser or app opens each URL, built for people who routinely juggle more than one browser.

What it is

Finicky is a macOS application that takes over the system's default browser role and then routes every incoming URL to whichever browser or URL-handling application the user's rules select. It is written in Go and distributed as a macOS app, with its configuration supplied as a JavaScript or TypeScript file at ~/.finicky.js. The project is developed on GitHub under the MIT licence and has around 5,102 stars and 212 forks, with 53 open issues.

The concrete problem it solves is the single-default-browser limitation on macOS. The operating system lets you set one default browser, so every link from Mail, a chat client, or any other application lands in the same place. Finicky replaces that single setting with rule-based routing: match patterns can send bsky.app URLs to Firefox and google.com URLs to Google Chrome. It also rewrites URLs before they are opened, forcing HTTPS or removing tracking parameters, so the address changes as part of the same rule that chose the browser.

Key capabilities

• A defaultBrowser setting plus a handlers array, where each handler pairs a match pattern with a browser such as "Firefox" or "Google Chrome".
• Match patterns that accept a single string ("bsky.app/*") or an array covering several patterns and subdomains ("*.google.com*").
• A rewrite array whose url function mutates the address before launch; the README example rewrites x.com/* to xcancel.com.
• Rules written in JavaScript or TypeScript for complete control, with regular expressions and custom functions for complex routing logic.
• One configuration file at ~/.finicky.js, with an example-config folder in the repository.
• Browser extensions for Chrome and Firefox that add an "open with Finicky" action to links and make alt-clicking a link open it in Finicky directly.
• Documented migration from Finicky 3 through a dedicated wiki page.

Who uses it and how

• People separating work and personal browsing across different browsers without resetting macOS preferences each time.
• Workflows that send social URLs such as Bluesky or Reddit to one browser and LinkedIn or Google Meet to another.
• Privacy-minded users who rewrite tracking-heavy links before they load, as in the x.com to xcancel.com example.
• Users wanting link-level control inside the browser, through the Chrome and Firefox extensions and their alt-click behaviour.
• Anyone troubleshooting routing; starting Finicky manually opens the configuration and troubleshooting window instead of only registering as the default browser.

Getting started

Install with brew install --cask finicky, or download from the releases page. Then create a JavaScript or TypeScript configuration at ~/.finicky.js, start Finicky from Applications, Spotlight, Alfred, or Raycast, and allow it to be set as the default browser.

How it compares

The facts name one comparable tool: Browserosaurus, an open source macOS browser prompter by Will Stone, which asks the user to pick a browser through a graphical interface rather than deciding from rules. The README says the two work well together, which places Finicky as the automated, configuration-driven counterpart to a manual picker.

When to use it — and when not to

Finicky is macOS-only and only useful if you are willing to make it the default browser and maintain a JavaScript or TypeScript configuration file. Anyone who wants zero configuration, or who works mainly on Windows or Linux, should not choose it. The README is short and the full configuration documentation lives in the project wiki, so expect to follow external links for the details.

// ~/.finicky.js
export default {
  defaultBrowser: "Google Chrome",
  rewrite: [
    {
      // Redirect all x.com urls to use xcancel.com
      match: "x.com/*",
      url: (url) => {
        url.host = "xcancel.com";
        return url;
      },
    },
  ],
  handlers: [
    {
      // Open all bsky.app urls in Firefox
      match: "bsky.app/*",
      browser: "Firefox",
    },
    {
      // Open google.com and *.google.com urls in Google Chrome
      match: [
        "google.com/*", // match google.com urls
        "*.google.com*", // also match google.com subdomains
      ],
      browser: "Google Chrome",
    },
  ],
};