A TenantMember is the link that places a User inside a Tenant with a specific level of access. It records the tenantId and userId it joins, the member's role (their TenantRole in that workspace), whether the membership isActive, and when the person joinedAt. It can also point at a notificationEmailId, choosing which of the user's verified addresses should receive that workspace's notifications. Because the same person can belong to several workspaces, each with a different role, the TenantMember record — not the user account itself — is what permission checks and member lists read to decide what someone may do in a given tenant.
Technical section
Data model, API, and internals — visible to developers.