I am a software engineer. While I was working for a previous employer I built a software system from scratch. Part of my employment agreement was anything made for that employer on company time or using company resources belonged to them. Approximately 6 months ago I left that position and took a position with a different company.

A few months ago I realized that several of the technologies and techniques I have learned while working with the new company could be applied to that system to make it much better. I have been thinking about rebuilding a similar system on my own and trying to sell it. As far as I am aware there are no patents or anything like that on any parts of the system.

Given that the new system will be very similar to the first system I built, and utilize many of the techniques I figured out while building the first system, will my former employer have any rights to the new system if it’s built entirely with my own personal resources?

  • Did your contract with your former employer contain any confidentially clause? Also this is likely to be governed in part by State law, so what is the jurisdiction you are concerned with?
    – sharur
    Mar 23, 2020 at 23:28
  • I do not recall any confidentiality clause in my employment agreement. I live and work in the state of Michigan
    – Noxerran
    Mar 23, 2020 at 23:43

1 Answer 1


The former employer owns the specific code that you wrote, but not the knowledge that acquired. If you copied chunks of code from the original that you wrote, that would be copyright infringement and the company could sue you. Re-using ideas that you got when you wrote this is okay, because ideas are not protected by copyright. It is, however, possible, that you acquired knowledge that is a trade secret and covered by a confidentiality agreement.

  • Comments are not for extended discussion; this conversation has been moved to chat.
    – Dale M
    Mar 24, 2020 at 23:19

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