According to my knowledge, open source software is free to use and distribute. If modified it should be distributed under the same license. But what about only using output of the programme?

Eg. Consider sharelatex and overleaf. They are well known online latex editors. While compiling latex code they use pdflatex program, which is open source. Now, as they are web-based they are not redistributing it, but they are using output of the program. It is fine till here, but when it comes to revenue. Do they have to pay royalties?

It will be great if someone can concentrate on lppl at http://www.latex-project.org/lppl/.


In general, the license of the software used to create a file doesn't have any influence on the possible licenses you can distribute that file under.

For example, if you use Microsoft Word to write a document, or gcc to compile a program, then the license of Word/gcc doesn't affect the license you can use for the document/program.

The reason that the license of a program usually doesn't affect the license of the output is because the output normally doesn't contain anything that can be seen as a copy of part of the program that created the output.
The same holds for the LaTeX programs mentioned in the question.

  • 2
    "the output normally doesn't contain anything that can be seen as a copy of part of the program that created the output" - while I am glad lawyers believe in that, I am not convinced it is actually true. May 15 '17 at 5:40
  • 4
    There are a few notable exceptions to this. A big one is parser generators like ANTLR and Bison. An ANTLR grammar is copied into the output of the grammar and Bison copies a large portion of itself into the output. In fact, Bison has a special exclusion from this part of the GPL because of this. en.m.wikipedia.org/wiki/…
    – RubberDuck
    May 16 '17 at 10:54
  • The exception I can think of to this is the AGPL which is based on the output being transmitted via network. But for the OP, it really depends on exactly what license pdflatex etc. are released under
    – ivanivan
    May 17 '17 at 17:18
  • 6
    @ivanivan, the AGPL is also only applicable to the program itself and not to any data that is processed by the program. May 17 '17 at 19:15
  • @O.R.Mapper For a program like this, I suspect the small parts that survive from the software into the output are not copyrightable to begin with?
    – endolith
    Sep 25 '19 at 16:47

Your "knowledge" in the first paragraph is not correct. Only some Open Source licenses require that modifications of the software must be also licensed under the same license. These licenses are often referred to as "copyleft" licenses; GPL, MPL, and EPL are examples of such licenses.

On your second paragraph, you specifically mention pdflatex and the LLPL. As you yourself write, the online LaTeX editors do not distribute the software; therefore there are no obligations spelled out in the license.

Whether there is commercial activity (or "it comes to revenue", as you put it), has no significance. One of the basic principles of Open Source is that the license allows any use of the software; therefore restrictions on commercial activity would automatically render the license non-Open Source.


In addition to other answers. Some Open Source licenses do impose conditions and obligations regarding output work. But you can't really generalize all Open Source licenses on this matter.

For example GPLv3 explicitly states that


Does a hypothetical document constitute a covered work? i.e. is it based on the software? - No. Thus it is not covered by the license.

On the other hand a program compiled with GCC and linked against its runtime library would be such covered work since it is based on the runtime library. To solve this GCC uses GCC Runtime Library Exception.

  • Yes. Basicaly licenses are here because of copyright law. If you are copying nothing you are violating nothing (make sure in the result of transformation of your data by the program copied nothing from the program that is covered by copyright). There is EULA, a form of contract outside of copyright law, usually put restrictions on the product; they are a diferent story...
    – gavenkoa
    Feb 6 at 20:11

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