The above answer applies to regular W-2 employees. If you are a contract employee, receiving a form 1099-NEC, instead of a W-2, the answer is different. Due to a 2019 court ruling in CA, if you are a sole proprietor and you provide services to a client located in CA, that income is taxable by CA - even if you never set foot in California.
Reference: https://www.coblentzlaw.com/california-office-of-tax-appeals-gives-precedential-authority-to-bindley...
