I am working on a Mozilla Firefox Add-on licensed under the MPL-2.0, and just got asked by a user if I have a version for Google Chrome. I'd like to say yes and accommodate this request. However, before investing the time and energy to learn a new environment, or getting user hopes up prematurely, I need to know if the MPL-2.0 license is compatible with the Google Chrome Web Store Agreement or License or whatever they call it. Although I just had found something which seemed pertinent, I was not sure if it was the right document, and I can't seem to easily find it again.

I am not the original creator of this add-on, but am in communication with the creator, who has given me full developer access on the AMO site, posting privileges on the Facebook page, and is likewise open-source aware and friendly, and supports my efforts to revive his project.

My primary objective is to develop this as free software for Mozilla Firefox, and leave behind code that others may learn from or contribute to. My secondary interest is to expand platform coverage to other browsers to meet user needs. My third wish would be to allow for possible monetization in the form of voluntary contributions of a user-selected amount with a developer-selected minimum that is reasonable (i.e. to cover cost of transaction and leave some behind). Any donations would probably go to expansion of online presence or some incentive or compensation to others who provide a service outside my core area of expertise (i.e. legal fees - if any, hosting, graphic design, SEO, etc).

If not strictly compatible, can I expand my options with licensing flexibility? I.e. if I can make the case to the creator and he agrees, perhaps dual-license the project, a separate license depending on the platform, etc.?

1 Answer 1


If you refer to https://developer.chrome.com/webstore/terms#license I cannot fathom a reason why MPL 2.0 or any open source license would not be OK.

You are basically granting Google some rights so that they can publish your app. The MPL allows this alright.

And in this agreement:

5.2 You grant to the user a non-exclusive, worldwide, and perpetual license to perform, display, and use the Products and any content contained in, accessed by, or transmitted through the Products in connection with Google Chrome. If you choose, you may include a separate end user license agreement (EULA) in your Product that will govern the user’s rights to the Products in lieu of the previous sentence.

Which means that your "EULA" (cough, cough) will be the MPL.

Now if you are now comfy with all this, ask a question on http://groups.google.com/a/chromium.org/group/chromium-apps/


  • Please allow me time to get around to reading answers, and seeing if any others come in with more info, and doing more searching, before reminding me to accept. ;-) Thank you for responding, and when I am satisfied that I know what I am doing, I'll mark the appropriate answer (if more than one come in). Also, thanks for verifying the Google Chrome Webstore License URL. I think that is the one I was looking at. I remember reading that paragraph. [P.S. sorry for multiple comment edits, couldn't seem to get the @ reply mechanism to work.]
    – user5094
    Commented May 19, 2016 at 11:26
  • It seems paragraph 5.2 declares a two sentence "mini-license". The first sentence is the entirety of the terms, and the 2nd sentence allows the paragraph to be "replaced" by a custom license, which may include many popular pre-defined free-and-open-source licenses. I'm not as familiar with the MPL 2.0, but it seems to be free of many of the encumbrances of the various GPL licences (with which I am slightly more familiar), while still granting reasonable protection to the open nature of the software.
    – user5094
    Commented May 19, 2016 at 12:45

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