New York Tax Law 631(B)(1)(B) states that New York-source income includes income attributable to "a business, trade, profession or occupation carried on in this state."
Since you don't work for a New York employer, and your work was not carried on in New York, the income from that work is not New York-sourced, and therefore it is not subject to NY taxation.
https://casetext.com/statute/consolidated-laws-of-new-york/chapter-tax/article-22-personal-income-ta...
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
