Under the Public Health Act, a food premises over 200 sq m needs a establishment licence from the local authority; 200 sq m or less needs a notification and a certificate before opening. Check land-use zoning and building rules first, and make sure food handlers have completed food sanitation training. If you sell beer, wine or spirits, you also need an excise alcohol sales licence from the Excise Department and must follow the 2008 Alcoholic Beverages Control Act. If the venue becomes entertainment-focused (live music, disco, karaoke), a separate entertainment-venue licence may apply, and Bangkok has extra local rules. Whether food is the main revenue determines how officials classify the business.