Install Any Firefox Android Extension via Custom Collections

This article provides a complete guide for Android developers and advanced users on how to bypass the default extension limitations in the mobile Firefox web browser. By creating a custom Add-ons Mozilla Org (AMO) collection and unlocking a hidden debug menu within the Firefox Android app, you can sideload and install almost any desktop extension directly onto your mobile device. This process involves setting up a Mozilla account collection, retrieving your specific user and collection IDs, enabling secret settings in the browser, and linking your custom repository.

Prerequisites

Before starting, ensure you have the following:

  • A Mozilla Account.
  • Firefox for Android installed (This method works best on Firefox Beta or Firefox Nightly, though the secret menu is also accessible on recent versions of Stable).

Step 1: Create a Custom AMO Collection

To tell Firefox which extensions you want to use, you must first group them into a custom collection on Mozilla's website.

  1. Open a web browser and log in to your account on the official Mozilla Add-ons website (addons.mozilla.org).
  2. Click on your profile icon in the top right corner and select View My Collections under the Tools section.
  3. Click Create a Collection.
  4. Enter a name for your collection. Note that the Collection Name (the URL slug at the end of the custom URL field) is what you will need later. Avoid using spaces.
  5. Set the privacy to Public or Accessible to only me (both work) and click Create Collection.
  6. Use the search bar provided to find and add the specific extensions you wish to install on your mobile browser.

Step 2: Locate Your User ID and Collection Name

Once your collection is created, look at the URL in your browser's address bar. It will follow this format: https://addons.mozilla.org/en-US/firefox/collections/12345678/my-collection/

Write down the two pieces of information from your specific URL:

  • Collection Owner (User ID): The long string of numbers (e.g., 12345678).
  • Collection Name: The text immediately following the numbers (e.g., my-collection).

Step 3: Unlock the Secret Settings in Firefox for Android

Next, you need to enable the hidden developer menu inside the mobile browser to access the custom collection input fields.

  1. Open the Firefox browser on your Android device.
  2. Tap the three-dot menu icon and select Settings.
  3. Scroll all the way to the bottom and tap About Firefox (or About Firefox Beta/Nightly).
  4. Tap the Firefox logo five times rapidly. A notification will appear at the bottom of the screen stating: Debug menu enabled.

Step 4: Apply the Custom AMO Collection ID

With the debug menu unlocked, you can now link your custom collection to the browser.

  1. Navigate back one screen to the main Settings menu.
  2. Scroll down to the Advanced section and tap on the newly revealed Custom Add-on Collection option.
  3. In the first field, enter your numeric Collection Owner (User ID).
  4. In the second field, enter your Collection Name (this is case-sensitive).
  5. Tap OK. Firefox will automatically close to apply the changes.

Step 5: Install Your Extensions

  1. Reopen the Firefox app on your Android device.
  2. Tap the three-dot menu icon and select Add-ons, then Add-ons Manager.
  3. The list of available extensions will now exclusively mirror the custom AMO collection you created.
  4. Tap the + icon next to any extension in your list to install it onto your mobile browser.