Set Gmail as Your Browser’s Default Email Client with a Simple Hack

  1. Open Gmail in Chrome.
  2. Press Ctrl+Shift+J (Windows) or Cmd+Opt+J (Mac) to open Chrome’s built-in JavaScript console.
  3. Paste the following into the console and press Enter:
     navigator.registerProtocolHandler("mailto",
                                      "https://mail.google.com/mail/?extsrc=mailto&url=%s",
                                      "Gmail");
  4. Chrome will prompt you, asking if you’d like to “Allow Gmail (mail.google.com) to open all email links?” Click the Use Gmail button.
  5. That’s it!