As always, discuss with a lawyer.
There is always the spirit of the agreement and the letter of the agreement. There is the nature of the industry and your right to earn a living. And there is the probability that an employer will go through the cost of enforcing it.
In practice, non-compete agreements are not enforced unless there was some serious harm to the former employer.
If you were jumping from a high-profile job at one company to a high-profile job at another company you would likely have many fans that would switch. That could do serious harm, and that could be enough for an employer to attempt to enforce the non-compete.
If you were working on a big-name product and immediately started a direct competitor for that product, that could do serious harm, an employer would likely attempt to enforce the non-compete.
If you were building your hobby project that was very similar to the product in your day job, and you release it around the same time as your day job's product and end up drawing customers away, an employer would likely attempt to enforce the non-compete.
But if you are just a peon in the company and you are not really competing with the company and your transition doesn't cause any kind of conflict or harm to the company, they probably won't care. And if they did care, they probably would not invest the small fortune needed to enforce the agreement.