> ## Documentation Index > Fetch the complete documentation index at: https://cal.com/help/llms.txt > Use this file to discover all available pages before exploring further. # Require/Exclude Email Domains (Booking Question) > Control who can book by requiring or excluding specific email domains like @company.com or public domains like @gmail.com. The **Email** field in Cal.com’s booking questions supports **domain-level restrictions**, allowing you to control who can (or can't) book time with you based on their email address. ### Use Case This is useful when: * You only want people from a specific company (e.g., `@company.com`) to book. * You want to **exclude free/public domains** like `@gmail.com` or `@yahoo.com`. * You're running internal meetings and only want your organization's members to access them. ### How to Configure Go to your Advanced settings of your Event type setup. Under \*\*Booking questions, \*\*find the Email field. Click on `Edit`next to the booking question, and you’ll see options to: * Require emails that contain (...) * Exclude emails that contain (...) Simply use the fields to specify or exclude email domains for your specific use case. BrandBird 2025-06-17 13.40.02.png