If I use the lgpl licensed javascript library, do I have to release a closed source web application that is using it?

I feel like it's unnecessary, as long as I don't modify the source of the library.

I want to use wysiwyg lgpl javascript in a commercial closed source environment.

A closed source web application is never distributed (depending on how the definition of distribution applies to web pages) and the end user only has access to it.

I find gpl and lgpl very confusing as they apply to the web.

I also don't understand what constitutes "distribution".

1 Answer 1


How the GPL applies in a Web context is not clear to me, either. Despite being served in discrete chunks as a result of distinct HTTP network fetches, does copyright law consider the application as a whole one work? It's unclear to me and not well-defined by existing case law.

However, the operation of the LGPL (rather than the GPL) can remain happily agnostic to the outcome of this question, since its copyleft extends only to a library and not to a whole application that uses the library. If your application uses an LGPL library in a way that the application code merely "combines with" the library (rather than modifies the library directly), you need only abide by copyleft requirements for that library and not your whole app. (See the phrase "Combined Work" throughout the LGPLv3 to understand its definition and copyleft requirements.)

The purpose of the LGPL is to allow use of LGPL libraries within closed-source proprietary applications, while still requiring disclosures of changes within the LGPL library itself. I would assume the an LPGL library file that provides WYSIWYG functions or objects for use elsewhere in your JavaScript application would not create copyleft obligations beyond the library itself.

How distribution applies to the Web is usually quite simple: if something ends up in RAM or storage on a user's computer in any form, then it has been distributed to them. If a piece of code lives on your own server and is never transmitted to a user in any form, then it has not been distributed. The client-side code of your application is distributed; each component that is (L)GPL-licensed must be accompanied with source code or with prominent offers for source code (but obviously any components not covered by copyleft licenses need not satisfy those copyleft requirements). Your server-side code is not distributed and creates no copyleft obligations (unless you use code under the much-stronger AGPL.)

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