Monetizing and licensing with AGPL libraries

Question

I am just curious about, what license should i use for app(android), i have written in my free time. I am using some libraries, which have this licenses on it:

• Apache 2.0 license
• MIT license
• GNU Affero General Public License

1 Question: if i use this libraries, should my app be open source? I have no problem with making it open, but just not sure if i should do it. And if yes, what is the best of doing it? Just say it is open source, and that everyone can contact me for the source code? Or do i have to upload it somewhere (sourceforge, github)?

2 Question: if i use this libraries, am i able to sell my app? If not, am i able to make in app purchases to donate to me? As much i know the biggest problem would be the AGPL license. I use the library to create PDF files (iText). How should it be handled? Or can i make some features paid, but not that one, which are from the AGPL licensed library?

3 Question: what is the best license to use with my app in that case?

Answer 1

The usual line is that you are making a derivative work of all three libraries. When you distribute that, each individual component library must be redistributed under its original licence. The resulting derivative work - the whole product - must be distributed under a licence that honours them all.

Since one of the components is AGPL3, the resulting product must be distributed under a licence which is at least as permissive as the GPL - such a licence is referred to as being GPL-compatible. The FSF maintains a list of such licences, and Apache 2.0, the MIT X11 licence, and the MIT Expat licence (you do not say to which you refer) are compatible.

So as I understand it - and remember I am not a lawyer, and even if I were, I'm not your lawyer - you must release each component under its original licence, and the combined work under any one of the three (or, if you want to complicate matters, any other AGPL3-compatible licence).

You also ask

am i able to sell my app?

Yes, of course; free software may be sold, and often is. But you may not deprive your users of the four freedoms; in brief, you must provide them with the source code, and the rights to use it.

am i able to make in app purchases to donate to me?

Yes, you may; but you may not prevent other people from removing or altering that code.

As much i know the biggest problem would be the AGPL license. I use the library to create PDF files (iText). How should it be handled?

I don't entirely understand this part of the question.

Or can i make some features paid, but not that one, which are from the AGPL licensed library?

You may certainly charge for features, but when you distribute them to paying users, you must include full source, and the rights to use it, so that users may redistribute them if they wish.

Finally, I should add that not everyone agrees that linking your code to another's library makes a derivative work. You should get advice on this question, because if it doesn't, everything I wrote except the second sentence is false. However, most people that I know do not take this position; that is, they accept that linking creates a derivative work, and thus that such a derivative will be bound by all the licences on its components.

Answer 2

The AGPL is, just like the original GPL, a so-called "Viral License". When your program uses an AGPL library, then your whole program must be licensed under the AGPL. That means you must publish the sourcecode and you must give people permission to create and distribute derivative works under the AGPL.

See also the GPL FAQ about this:

Q: If a library is released under the GPL (not the LGPL), does that mean that any software which uses it has to be under the GPL or a GPL-compatible license?

A: Yes, because the software as it is actually run includes the library.

(technically this FAQ entry is about the GPL, not the AGPL, but the AGPL is an even stricter version of the GPL)

The sourcecode does not need to be part of the app, but when it is not, you must:

Accompany it with a written offer, valid for at least three years, to give any third party, for a charge no more than your cost of physically performing source distribution, a complete machine-readable copy of the corresponding source code, to be distributed under the terms of Sections 1 and 2 above on a medium customarily used for software interchange;

Technically the AGPL does not prevent you from selling your app. Open source licenses do not forbid any money from changing hands. But unfortunately everyone who buys your app has the right to also sell your app or even give it away for free, so they can put your app onto the app store for free and there is nothing you can do about it.

Voluntary donations, on the other hand, can be a viable monetization model for open source.