Inclusion Criteria:  Hong Kong residents aged 18 or above Smoke at least 1 tobacco stick (includes HTP) per day or use e-cigarette daily in the past 3-month Able to communicate in Chinese Saliva cotinine 30 ng/ml or above Intent to quit/reduce smoking Able to use the instant messaging tool (e.g., WhatsApp, WeChat) for communication  Exclusion Criteria:  Smokers who have communication barrier (either physically or cognitively) Smokers who are currently participating in other SC programmes or services