Comment The Law's Not On Your Side. Are Your Skillz? (Score 1) 848
Legally...
IANAL etc. but I do see pretty similar happening all the time...
Are you using ideas and concepts you learned at that place of employment? Are you developing software specific to their environment? It sounds a lot like it. If so, they've got a pretty good case that you're using the benefit of their privileged information in order to develop this product and thus, yes, they have a pretty good claim on it.
Also, be careful what you say in massively public stories on very public websites. You say, "The entire source was developed on personal equipment off company hours." You also write, "I have a lot of down time." I'd say, "Which one is it?" but it doesn't matter. You've now publicly said the latter. Even if you meant it in terms of, "I have a lot of down time at home," you didn't say that when announcing it to the world. In a court filing, they'll present it nicely out of context as a clear admission on your part that you used downtime they were paying you for.
You've given enough ammunition, if an employer is sue happy, for them to drag you through the courts long enough to bankrupt you. At the point you can't pay a lawyer to defend another round of investigation and have to settle, they own the idea anyway. Don't make the mistake of thinking courts are about the person in the right winning: most business vs. small individual stuff is about them running up your legal bills until you can't fight back. You will lose.
Pay Grade And Leet Skillz...
If your skills are that wonderful and you can genuinely charge for them at a higher pay grade, why aren't you? If you can do so, leave, collect that higher pay grade, fulfill your belief in people "not getting something for nothing." At the very least, an offer in writing from somewhere else may serve as leverage for your getting the pay grade you clearly feel entitled to.
Unless, of course, you're not that good. Don't worry: a lot of people can do basic enough hacking of code that they can get something sort of working if there are low expectations for it. They make great personal tools but it's also not the level someone'll pay you for as they expect it to work properly, all the time, with all the features they can think of and not just the easy ones. If that's the case, you're not going to get that pay grade you deserve elsewhere and that should tell you something about how much you genuinely deserve it where you are. If that is the case, you're at best going to deliver them some nice hacky tools and you're probably already being compensated for that kind of development. Not stating this is your level, you may well be capable of the former option. But it's always worth taking an honest self assesment before getting entitlement complexes.