I work for a local county that will generate our local tax statements for free via a web service consumable by a public URL. For example, the web service would generate and stream the PDF using the URL below.


The service is an independent project of other systems in our organization and retrieves the data in our SQL Server database.

To generate the PDF, I will be using PDFtk in the project. The product is GPL version 2. I've read countless discussions, and from what I understand is that as long as I dont distribute my project, I dont have to make my project source code available. But I'm not a lawyer, and I want to be 100% sure. Even on the PDFtk website, it says:

If you plan to distribute PDFtk Server as part of your own software, you will need a PDFtk Server Redistribution License. The exception to this rule is if your software is licensed to the public under the GPL or another compatible license.

I have a two-part question:

Do I understand the GPL v2 license correctly that as long as I don't distribute my web service code, I dont break the license agreement with PDFtk and GPL v2?

And if I did misunderstand how GPL v2 works in conjunction with PDFtk, How would I make my web service GPL complaint? I have a GitHub repository that I can put the source code into. But how do I let the consumer know that the service they are using falls under GPL? Is it enough that they go to my service website, where I display some GPL information before the tax statement is generated? And if it is, what do I put? And if not, what is the proper way to do it?

I really appreciate any help you can provide.

  • Ask the county's legal department.
    – BlueDogRanch
    Aug 3, 2023 at 14:03
  • Why is this a downvote? I'm asking a legit question. Our legal department may not know the answer if they haven't dealt with it before. It was suggested to me to ask here for some advice.
    – adviner
    Aug 3, 2023 at 14:09
  • 3
    The Open Source SE site would be a much better fit.
    – Jon Custer
    Aug 3, 2023 at 14:34
  • 1
    It is certainly peculiar that you need to purchase a redistribution license when GPLv2 already allows redistribution. GPLv2's viral effects are also not applicable to aggregates. And since it runs as a command line tool, it will always be an aggregate. It would make more sense if it were to be a library than a command line tool.
    – ruben2020
    Aug 3, 2023 at 22:27
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    Are you making changes to PDFtk? Then the GPL basically means you have to make those changes available under the same license to the site owner/operator. It doesn't mean that the server operator needs to make source available to visitors that are using that tool indirectly, however. It's a bit analogous to a web server running Linux. Linux is GPLv2, but running your site using that software (Linux) does not mean that you have to offer every visitor to your server, the source code to your copy of Linux (which might be slightly different from the Github/publicized version, for example).
    – Brandin
    Aug 8, 2023 at 7:27


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