Submit or Manage Extensions

Prompt users for data and privacy consents

If your extension collects user data, it must comply with the requirement of the Data Disclosure, Collection and Management section of the Add-on Policies.

A common developer question about these policies is how to translate them into browser extension features that are compliant to Mozilla’s Add-on policies. This how-to is the result of those requests and offers advice on implementing prompts to meet the data collection and add-on policies. This article suggests how you can implement suitable prompts but it doesn’t replace or supersede the policies; you still need to confirm that your extension complies with the policies.

Firefox provides a built-in consent for data collection and transmission in Firefox for desktop 140 and later, and Firefox for Android 142 and later. See Firefox built-in consent for data collection and transmission.

If your extension is installed in an enterprise via the force_installed or normal_installed options in the ExtensionSettings enterprise policy, you must still implement the disclosure and consent experience in the add-on.
You can set a value via the 3rdparty enterprise policy and read it with storage.managed in the add-on to determine if consent is granted. You must display the disclosure and consent experience if the value is not set in storage.managed.

Know your privacy settings

To create the consent flow and consent dialogs your extension needs, you should first answer these questions:

  1. Does my extension collect technical or interaction data? If so, offer the user the opportunity to opt-out of this data collection, although you can always offer opt-in consent if you prefer.
  2. Does my extension collect personally identifying information? If so, get the user’s opt-in consent before collecting any of this data. Remember that personally identifying information includes technical or interaction data tagged with the user’s identity or information that can be used to identify the user, such as an URL.

If you are unsure whether your add-on collects personal, technical, or interaction data, refer to the definition in Data Disclosure, Collection and Management.

“Data” includes all information the extension collects, regardless of the manner of collection or the reason for collection. This also includes data collected as part of the extension’s primary functionality.

Data sent to native applications using NativeMessaging must be declared in the data collection consent and categorized in the appropriate consent model (whether opt-in or opt-out).

Get prepared

Before designing the data collection consent for your extension, you should:

  • eliminate any unnecessary data collection.
  • design your extension to offer as much functionality as possible if the user declines the collection of data.
  • (optional) create a privacy policy.

While a privacy policy is not required, it can help users better understand what data your extension uses and how that data is used.

Prompt after install

As part of your extension’s onboarding flow, include information about your privacy policy and data collection and seek any necessary user consent. Any privacy information and settings should be clear and unmissable. Separating these details from general information about your extension can help. Using a new tab in the focused window is recommended.

For more information on how to implement a post-install page or dialog, see Best practices for onboarding, upboarding, and offboarding users.

As mentioned in the Add-on policies, if your extension collects user data in association with features that run in the background, such as ad blocking, you need to make sure the data collection is not activated until you have obtained user consent.

If an update to your extension collects new personally identifying information, existing users must consent to the new data collection (opt-in) when your extension updates.

We have talked about how you could let users opt-out of collecting technical and interaction data but must have users opt-in to collecting personally identifying information. Before you design your extension features around your consent requests, it is important to understand how these options affect your design.

Where you provide the user with an opt-in option, the related feature must be turned off by default and only turned on once the user has actively agreed to use that feature.

Where you provide the user with an opt-out option, the related features can be turned on by default but must be turned off if the user indicates they want to opt-out.

If the primary function of your extension requires collecting user data, provide an option in the data collection consent to uninstall it if your users don't consent to the data collection. The management.uninstallSelf() API can be used to uninstall your extension. Name the consent decline button appropriately, such as “Decline and uninstall”.

Data classification

It is important to classify data into its right category and set defaults accordingly. Mozilla's add-on policies require an opt-in data collection consent for personally identifiable data and opt-out for technical and user interaction data.

Incorrect classification of data on the data collection consent will result in a review rejection.