What is the decisive difference between LGPL(v3) and AGPL(v3) ?

Both can be used in commercial production, both can also be packed within a payed product. As long as I do not change the source code of these, I am not forced to enclose the source code with my product.

So where lies the eminent difference?

(Asked this also at https://stackoverflow.com/questions/10996160/the-decisive-difference-between-lgpl-and-agpl, but a user suggested to ask it here.)


1 Answer 1


roughly, as long as you application isn't just a wrapper around the library:

  • LGPL: you can link against and don't have to release source code as long as you don't modify the library itself
  • GPL: you have to release source code if you link against and distribute the binary, but don't if you just provide a service
  • AGPL: you have to allow the source to be downloaded even if you never distribute the binary but do provide a service

i.e. your understanding of the LGPL is probably correct but your understanding of the AGPL is very wrong

as always if you want proper advice for your use-case you need to hire a lawyer

  • 1
    thanks jk - your answer is great! Imagine, I use MongoDB (which is licensed under AGPL) and provide a commercial website for users. Does every user need to know, that she is allowed to download the source of my website? How should I fullfill AGPL in such a case?
    – nimo23
    Jun 12, 2012 at 13:48
  • every user should be able to download the source, how prominently you need to advertise this I do not know, you would need a lawyer to advise on that
    – jk.
    Jun 12, 2012 at 14:00
  • 1
    @nimo23 : more precisely about MongoDB licensing, you are safe because they clearly state that we promise that your client application which uses the database is a separate work see here : mongodb.org/display/DOCS/Licensing
    – Justin T.
    Jun 12, 2012 at 17:02
  • @Justin T: what does "...is a separate work" mean? Imagine 2 scenarios: scenario I: "I have a commercial website online and I use mongodb as a backend, so all users can use my website and I am not forced to adhere to terms of AGPL as my website is a separate work". Scenario II: "I have a website and I use mongodb as a backend, I will sell the website to other customer and I am not forced to adhere to terms of AGPL as my website is a separate work". Are the 2 scenarios legal and right?
    – nimo23
    Jun 13, 2012 at 11:30
  • 2
    @nimo23 Both scenarios are legal as long as you sell your work (the coding) and not the database server itself, nor the mongodb sources. You still can sell any separate services for installing and maintaining mongodb servers. Hope this helps !
    – Justin T.
    Jun 13, 2012 at 13:31

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