Note in you contract before you begin that you retain copyright to the code you're developing, and are licensing them an instance of it. Then you're free to rel

Note in you contract before you begin that you retain copyright to the code you're developing, and are licensing them an instance of it. Then you're free to release a "for the public" version as you like. If you haven't got that kind of agreement in place already, then it'd be polite to discuss it with them first. If they assert ownership of your code with out you having agreed tot hat beforehand, you probably want to know that now anyway, before you do any more work for them. There's nothing wrong with such an arrangement but its best to be explicitly clear about these terms, and them having copyright or an exclusion on your use of the code you develop is worth more compensation.