I'm creating software which includes (PHP library for generating PDF documents on-the-fly) to export invoices which falls under GNU Lesser General Public License, the open source product is called tcpdf.

What does this mean for me? I plan on charging for my software. This software makes up a very small part of our entire software function. If I utilize this in my software do I have to release my full source code of my project?

  • 5
    I'll see if we have a canonical question about LGPL requirements, but in short: if you use LGPL'd code as a library that is logically separable from your larger application then your source-disclosure requirements only apply to the library itself (and any changes you make to the library itself), not to your whole application. That is the primary difference between the GPL and the LGPL.
    – apsillers
    Nov 18, 2020 at 22:37
  • Yep. The purpose of LGPL is actually that usage.
    – Peter
    Nov 19, 2020 at 20:49

1 Answer 1


No, although you do have to release the source code of the library itself.

However, your application must allow someone to use their own, modified version of the library.

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