I worked with a company (Company A) in the US as a developer for two years that utilized third party API's. I recently left that company to work elsewhere (new company (Company B) is a completely different type of company, no technology overlap whatsoever). However, I've recently been looking into starting a side project. This side project, while not using any code of Company A, is based upon my experience of working there, particularly with one third party API. My goal is to write something that would be open sourced and make dealing with said third party API more bearable.
My question is, if my former employer finds out that I've done this, do they have any grounds for suing me? Are there any repercussions that could occur for me pursuing said side project?