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pjullrich/google-account-select-extension

pjullrich /

Google Account Switcher — Firefox Extension

A Firefox extension that automatically sets the authuser URL parameter on Google services so you always land on the correct account.

Why?

Google defaults to your first signed-in account whenever you visit a Google service. This extension intercepts requests to Google domains and injects the right authuser=N parameter based on your preferences — globally or per-service.

If you manually switch accounts on a page, the extension won't interfere — it only acts on URLs that don't already specify an account.

Install

  1. Go to the Add-on Page
  2. Click on the latest version and then click on the .xpi file to download it.
  3. Firefox will ask you whether you want to install the extension. Say Yes. If it doesn't, you can double-click the .xpi file to install it.

Setup

1. Import accounts

Click the extension icon and use Import from Google to detect all signed-in accounts and their current indices. This fetches from Google's ListAccounts endpoint using your session cookies — nothing leaves your browser.

Account indices are based on sign-in order and can shift if you log in or out. The extension identifies accounts by email, so your preferences survive index changes. Click Import from Google again to refresh indices.

2. Set a default account

Use the Default Account dropdown to pick which account is used across all Google services.

3. Per-service overrides (optional)

Use Add service… to override specific services. For example, set Gmail to your work account and Maps to your personal account.

Supported services: Calendar, Chat, Contacts, Docs, Drive, Groups, Keep, Gmail, Maps, Meet, Photos, Sheets, Slides.

Dev

Zip the extension to submit it in the Firefox Add-on Store:

zip -r account-switcher.zip manifest.json background.js popup/ icons/

Permissions

  • webRequest / webRequestBlocking — intercept and redirect requests before they reach Google.
  • storage — persist account list, default, and overrides locally.
  • activeTab — inject a script into a Google tab to fetch the signed-in accounts list.
  • Host permission *.google.com — the only domain the extension operates on. No data is collected or sent anywhere.