packages/twenty-shared/src/constants/SubdomainPattern.ts

// 3–30 chars: lowercase alphanumeric and hyphens, must start and end
// with a letter or number, must not start with "api-"
export const SUBDOMAIN_PATTERN = /^(?!api-)[a-z0-9][a-z0-9-]{1,28}[a-z0-9]$/;