The legality of who owns that work will depend on your work contract and your local employment law.
You very well might create something, turn around to sell it to them, and find out that your employer legally owns the copyright to the work even if you did it on your own time with your own resources.
Employment law is nuanced.
Tldr; bring your work contract and your idea to a meeting with an employment attorney and ask them who would own this work.
You very well might create something, turn around to sell it to them, and find out that your employer legally owns the copyright to the work even if you did it on your own time with your own resources.
Employment law is nuanced.
Tldr; bring your work contract and your idea to a meeting with an employment attorney and ask them who would own this work.