Hosted multi-tenant application with per-tenant unshared private databases

Technologies are described herein for providing a hosted multi-tenant application that utilizes per-tenant unshared private databases. A shared middle-tier is utilized in conjunction with private, unshared databases for each of the tenants. The private, unshared databases are utilized to store application data for an associated tenant, along with any customizations to the application implemented by the tenant. A shared configuration database is also utilized that stores application data that is shared among the tenants. When a request is received from a tenant to access the hosted application, the shared configuration database is utilized to locate the private, unshared database associated with the tenant making the request. The contents of the private, unshared database associated with the tenant making the request are then utilized to response to the request.