Legal Question in Employment Law in California

You would need to provide more details about your contract to get a reliable answer. As a general principal, employers absolutely cannot charge a "quitting" fee to employee's who want to quit their job. They can, however, contract for reimbursement of certain fees, expenses, advances, and similar payments if not "earned" by staying with the employer for a certain amount of time. The rules are also different for true independent contractors, although a very large percentage of supposedly independent contractors in the software industry are actually legally employees and are illegally being treated as contractors. So the bottom line is that without reviewing your contract and the facts and details of your employment/work for the consultancy, there is no way to answer your question reliably.