Can I sell computer source code that I reuse in other applications that I still sell?

Question

I have several different versions of the same software (written in .Net/WPF) that interact with different brands of hardware. I decided to discontinue one of the platforms. The company that sells the hardware for that platform approached me about purchasing the software source code from me so they can continue to sell the software to their customers.

So, I would rework the UI and rebrand it so it doesn't look exactly like the other versions of the software, and they could claim it as their own. My question is, is there a way for me to sell and give them the source, without putting myself in legal danger since 50% of the source code is still in use with the other versions of the program I will continue selling?

The client is fully aware of the situation, and is not interested in exclusive rights to the code. They just want to be able to take it over (and modify it if need be) so they can continue to sell it.

Answer 1

The answer by Dale M. is correct, but a bit brief.

"Selling" is not an exact phrase.

What you do not want to do is to transfer ("sell") the copyright to the source code. If you did that, you would put yourself in legal danger because they now own the copyright to code that you use in other products, and can sue you for copyright infringement.

However, you selling a copy of source code does not imply transfer of copyright in any shape of form. When you buy a copy of a book in a book store, the author's copyright is not transferred to you. Accepting this deal would put the other party in legal danger. Even if they have bought the source code, they still don't have a license to make further copies of it and sell those.

This is why you need to license the software to them.

In brief: Copyright grants the copyright owner a lot of rights. These rights are always licensed, not sold. The right that is relevant here is the right to create derivative works.

A license is simply a contract between the two parties, describing a particular business arrangement in legally binding terms.

If I were in your position, I would hire an IP lawyer to help drafting the license. But, basically, the license should say that you, as owner of the copyright to ABC software, grants XYZ company access to its source in its present form, and also grants XYZ company the right to create derivative works, but only for hardware platform DEF, and to create and distribute copies of their derivative work.

Answer 2

Don’t sell it, license it instead.