[bitwize]

Many employment contracts are phrased in such a way as to say that the company owns ALL your creative output. Whether that's enforceable depends on jurisdiction, so hire a good lawyer before working on that side project, disclose it to your employer and get it cleared by their legal department.

There's a reason why the GNU project requires an explicit waiver from the contributor's employer for all contributions. Anything less puts them at risk of civil or criminal liability.