A javascript application release won't technically be closed source - at best it can be obfuscated. Given that, my question has two parts:

  • Is it at all possible to release a technically open source application under a proprietary license?
  • Are there any examples of applications which are technically open source, have been kept under a proprietary license, and are being profitably sold?
  • I think 'source code distributed' is probably closer to the mark than 'technically open source' which has different connotations
    – jk.
    Commented Feb 24, 2011 at 8:57

5 Answers 5


Just because you have the source code does not mean that something is "open source". Open source means you have the right to use and modify the source yourself.

As a quick example, Valve's HL2 source code was stolen and leaked, but it's still proprietary, it would be illegal for someone to steal it and use it in their own application (without licensing it from Valve), and Valve continue to make and sell (for profit) games based on that engine.

  • 1
    It's still 'open source' in that the source is readily available and people can use it. Whether they should or not isn't up for debate. Commented Feb 24, 2011 at 3:28
  • 2
    Well... The problem with this is that if someone has an API reference and knows a website that uses this javascript file, they can always just link it from the site. I think in the case of javascript it's just better to give up on the proprietary aspect of it though. Users of your program download the source code every time they use your program.
    – Earlz
    Commented Feb 24, 2011 at 4:44

Yes, just because somebody has access to the source gives them no right to copy it and use it.

Off the top of my head, I know of several javascript charting libraries that are being sold.

  • Can you please list one or two? Thanks. Commented Feb 24, 2011 at 5:30
  • 2
    @blueberryfiels - Higcharts.com is one of them. Commented Feb 24, 2011 at 6:02

I think the term you are looking for is "commercial license" instead of "closed-source license". As you've noted, the source is technically "open" since it is not compiled or otherwise obfuscated.

Not all open-source software is free open-source. Even projects that have free versions can offer commercial licenses for extended versions or just for licensing purposes (ie, the open-source license can't be used as a part of another software).

This is a subject I am very familiar, seeing that I'm one of the founders at a source-code marketplace named Binpress - we have both free and commercial source-code packages on our service, and there's no contradiction. We have a page detailing the important points of such commercial licenses, which I think you will find useful.


You're confusing a lot of terms. Here's some definitions to help you out:

  • Open Source - The copyright owner has allowed people to view and modify the source, create derivatives, etc...

  • Closed Source - The copyright owner has not provided these privileges

  • Commercial Software - software written for money. Believe it or not, a LOT of open source projects fall in this category.

Consider books. I buy a book, I can open the book. Having opened the book, and assuming it's in a language I understand, I can read the book. All the words are there for me to view. I still can't make copies of the book and sell them or give them away (depending on jurisdiction). In this regard, the book is Closed Source.

On the other hand, many books and articles distributed under a Creative Commons license (depending on options) CAN be copied and given away legally. These books, being no different from Closed Source books as far as readability is concerned, are Open Source.


Your best bet is obfuscation.

In some ways a compiler can be considered an obfuscator too because all it does is translate source code into machine code; there are equally tools to decompile, or de-obfuscate the code too. Along with refactoring tools, it can be relatively easy to reverse engineer a compiled application to source code again.

As to examples, I can't think of any off the top of my head, sorry.

Edit: Actually, I lie. CKEditor is a JS-based WYSIWYG editor that has a paid-for licensing option for people who want to embed it into their own products that they sell, eg. Kentico uses this licence to include CKEditor in their own product.

  • 1
    I don't think that's what the OP was asking. They weren't asking if they could obfuscate the code.
    – MarkR
    Commented Feb 24, 2011 at 7:46

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