I work at a FAANG-size company (moonlighting friendly in theory) and have a side project that I've built mostly in my free time, a bit during work hours, and had it recently approved by the legal department for open-sourcing and it's now available in public on GitHub with an MIT license for everything.

Since the MIT license allows anyone to do whatever they want with the project, including commercial use and creating derivatives, I'm tempted now to create a startup based on the project - basically fork it and work in private on it, extending and improving it a lot (make it worth buying it compared to OSS version), then rebrand and launch it as a subscription app.

This future work would not touch any company-owned hardware and resources, unlike the work that got open-sourced (that was the reason it's now on the company's GitHub account and not mine, was happy enough open-sourcing went smoothly through approvals).

The moonlighting policy is fairly permissive, but also somewhat vague especially about what a competing product is (whole product or a small module in a larger product is enough). The other restrictions are the usual, don't use company hardware, time, connections to do the work.

There are several concerns I have and I'm also curious if others have dealt with a similar situation and have some advice:

- my fear is that even if I'm following the moonlighting policies from now on, they could later still claim ownership of my work based on the pre-OSS work. If someone else outside the company would fork the OSS repo there should be no problems given the MIT license, it's what these companies are doing all the time by wrapping Postgres and the like... - the company doesn't have a stand-alone product it sells similar to my app, but there is one small module similar to it part of a huge app. I assume that is enough to argue that my app is a competitor if one wants to.

Given this, feels like safest would be to quit my job before even starting to work on this, but of course I'd like to avoid that, with the startup maybe not working out. Switching to another company is another option, but seems others have even worse or no moonlighting. Last option, work on it while employed and hope I won't get sued. Maybe quit around the time I'm close to be done with a v1 and start marketing to reduce risk a bit.

As for the company itself, I'm not seeking funding and don't see it getting to some multi-million/y business, at best enough to make a full-time job out of it. Maybe that's enough to not make it worth suing.