@Critter-3 's answer is correct if you're a W-2 employee. But if you're an independent contractor (you receive a 1099-MISC instead of a W-2), any income you derive from services provided to California customers is taxable by CA. See this reference:
https://www.coblentzlaw.com/california-office-of-tax-appeals-gives-precedential-authority-to-bindley...
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
