Commercial product based on TDLib (Telegram). How to be?

Question

Copyright

Good afternoon.
Please tell me - can I create a mobile application based on TDLib and sell it? Or can I use this library only for "open" projects?
Or are things quite different than I can imagine?
Thank you in advance.

Answer 1

IANAL, TINLA.
> Please tell me - can I create a mobile application based on TDLib and sell it?
TDLib is licensed under the terms of the Boost Software License. See LICENSE_1_0.txt for more information" .
First, there is absolutely nothing stopping us from reading this LICENSE_1_0.txt:
Boost Software License - Version 1.0 - August 17th, 2003
Permission is hereby granted, free of charge, to any person or organization
obtaining a copy of the software and accompanying documentation covered by
this license (the "Software") to use, reproduce, display, distribute,
execute, and transmit the Software, and to prepare derivative works of the
Software, and to permit third-parties to whom the Software is furnished to
do so, all subject to the following:
The copyright notices in the Software and this entire statement, including
the above license grant, this restriction and the following disclaimer,
must be included in all copies of the Software, in whole or in part, and
all derivative works of the Software, unless such copies or derivative
works are solely in the form of machine-executable object code generated by
a source language processor.
<disclaimer here - Z.>
- and make sure that it is rather superficially written, and in particular, it does not, strictly speaking, give a direct answer to your question about sales.
So let's turn to the canonical Miscellaneous Licenses and Their Commentaries, edited by the FSF Licensing Lab, and find that this license is described there [0] as follows:
Boost Software License (#boost)
This is a lax permissive free software license copyleft-free, GNU GPL compliant.
So, a certain program under the terms of one license "Busta" should be free, which by definition [1] would mean that on its basis you can write mobile or any other applications and sell them.
[0] https://www.gnu.org/licenses/license-list.ru.html#boost
[1] https://www.gnu.org/philosophy/free-sw.ru.html
Now you should make sure that the program you are interested in is indeed distributed under the terms of the Busta license. Let's take its sources [2] and run licensecheck(1p) over them.
I beg to omit the full conclusion, but the gist is this:
Most of the files are really unambiguously labeled BSL 1.0:

...
./td/mtproto/AuthData.cpp: BSL (v1.0)
./td/mtproto/AuthData.h: BSL (v1.0)
./td/mtproto/AuthKey.h: BSL (v1.0)
./td/mtproto/CryptoStorer.h: BSL (v1.0)
./td/mtproto/Handshake.cpp: BSL (v1.0)
...

On many files nothing is marked, but this is all, as far as I can see, either assembly rules (or anything at all to help the developer), or settings templates:

...
./td/generate/scheme/mtproto_api.tl: *No copyright* UNKNOWN
./td/generate/scheme/mtproto_api.tlo: UNKNOWN
./td/generate/scheme/secret_api.tl: *No copyright* UNKNOWN
./td/generate/scheme/secret_api.tlo: UNKNOWN
./td/generate/scheme/td_api.tl: *No copyright* UNKNOWN
./td/generate/scheme/td_api.tlo: *No copyright* UNKNOWN
./td/generate/scheme/telegram_api.tl: *No copyright* UNKNOWN
./td/generate/scheme/telegram_api.tlo: UNKNOWN
./td/generate/scheme/update-tlo.sh: *No copyright* UNKNOWN
./tdutils/td/utils/config.h.in: *No copyright* UNKNOWN
...

Two samples you don't need:

...
./example/go/main.go: *No copyright* UNKNOWN
./example/ruby/example.rb: *No copyright* UNKNOWN
...

And finally, in the ./sqlite directory there is some local version of SQLite, which for some reason is here under the terms of a three-point BSD license issued by a certain ZETETIC, although the original is distributed as a so-called. "public domain" and by no means ZETETIC'om.
(Check the reference [3] for yourself if you want. :-)
[2] https://github.com/tdlib/td
[3] https://www.gnu.org/licenses/license-list.ru. html#... Thus, it is worth thinking that the TDLib library is really free, which means that you can write mobile or any other applications based on it and sell them
> Or can I use this library only for
> "open" projects?
HWhatever you mean, by the strange word "open", all the requirements of the "Busta" license and the three-clause BSD license essentially come down to the fact that you should somehow reproduce the names of the owners of the work, and the text of these licenses.
If you're asking if your application doesn't have to be free so you can include TDLib in it, then no, it doesn't. This is what the words “non-liberal non-restrictive” and “copyleft-free” from the list of “Various licenses” tell you.
Which should in no way be understood as advice to make your program proprietary. I dare to suggest that although the authors of TDLib give you such a right, they still rely on your decency.
> Or are things quite different than I can imagine?
Dbut, it seemed to me that you share the delusion that supposedly free ones cannot be sold. Although, of course, free software can be sold and useful (that's why they are free ;-).

Answer 2

Go to the License section in the documentation and read
and a link to this license
www.boost.org/LICENSE_1_0.txt
The license is short and unintelligent.
You can.