Is it effective to resign by email, WeChat or SMS?

Invalid, does not conform to the provisions of the labor law and the labor contract law.

Article 3 1 of the Labor Law stipulates that a worker shall notify the employer in writing 30 days in advance when he terminates the labor contract.

Article 37 of the Labor Contract Law: The employee may terminate the labor contract by giving a written notice to the employer 30 days in advance. The employee may terminate the labor contract by notifying the employer three days in advance during the probation period.