Legal Question in Business Law in California

That would be up to your employer. There is no legal barrier, but your employer has a right to limitations on "moon lighting."

Subject to a couple of exceptions, as Tim stated there is no per se legal barrier to your having your own business at the same time as you work for someone else. The exceptions generally relate to issues such as using the information, trade secrets and/or resources of your employer to help your separate business or compeating with your employer. If you have a written employment contract with your employer, that too could have terms which relate to what you can do. Generally such terms are vague and relate to things such as devoting your full working time to your employment. Keep in mind, of course, your employer could seek to terminate you if the time you are spending on your separate business interfers with your job.

Generally speaking you can do what you want on your own time as long as it is legal. Despite what many employment agreements say, you can work for whoever you want even a competitor as long as it is on our own time. This is especially true if you are a part time employee. If you are upper management or a supervisor that is key to running the business then the company may be able to place some restrictions on you.

Again so as long as your other business doesn't interfere with your current job you should be ok. If they fire you because of it, go see an employment lawyer or the labor Commissioner ASAP as that is illegal and you would have a good case against them.

Good luck.

I agree with the previous answers. I would, however, like to comment on another possible aspect of the question. Namely, what factors make the new business a Texas business, and for what purposes? If you form a Texas corporation and run it from your home in California, it may be a Texas business for some purposes, and a California business for others, including registering with the California Secretary of State and paying California's corporate franchise tax.