One login should be enough to run everything you publish — a portfolio, three client sites, and a storefront — without those properties ever bleeding into each other. That's the tension multi-tenancy resolves, and in Aglyn it isn't a feature we bolted on. It's the shape of the platform.
An organization is the unit of ownership: members, roles, billing, and shared assets live at the org level. Your team joins once, gets a role, and sees exactly the sites that role allows. Agencies run each client in its own org or group sites under one — both work.
Each site — we call the runtime a host — has its own screens, content collections, media library, forms, and domain. Nothing leaks across hosts by default: a collaborator scoped to one site can't wander into another, and one site's data model never collides with its neighbor's.
Isolation without sharing would mean duplicating everything, so the org layer carries what should be common: org-level media shared with chosen sites, members who span projects, one bill for all of it.
Because tenancy is enforced in the data model and security rules — not in UI filters — the guarantees hold everywhere: in the console, in the editor, on the published sites, and through the API. That's what "multi-tenant by design" means: the walls were poured with the foundation.