To be more accurate California is an at will state (for everybody: low level employees and CEO's) and non-compete are illegal. Other states are different. It exists to protect the interests of employees. The flipside is if you do resign you don't have to wait 2 months before you leave. It is good practice though to give at least a two week notice.
My understanding was that in At-will states, an employer-employee relationship could be terminated without reason or notice unless there is a contract in place that says otherwise. My (naïve) presumption was that companies would want to put these kinds of contracts in place for their senior leadership.
Those contracts are not enforceable. I guarantee you a win 100% of the time in California.
There are several exceptions:
1) you are the CEO or a top exec in a VERY large company. In that case your personal lawyers are involved in the negotiation of the contract, and it is assumed that you know what you are doing. But even in those rare cases, the law in on your side.
2) a non-compete COULD be part of the sale of your company (I wrote YOUR company, you own it, and your are not merely an employee, even senior employee).
Don't confuse that with the IP rights you give up to the company (legales like like we own EVERYTHING you have created or will create). You can still quit tomorrow with no notice given and work for whomever you feel like. Don’t use that IP, and don’t take ANYTHING with you (no files, no customers lists, no lines of code, no presentations, no emails). Then you are fine.
by default every employee in the US is "at-will" and can quit or be fired at any time unless they have a contract or are in union which has a contract.
