A multi-tenant collaborative review service that facilitates collaborative review of a review target artifact set. The service is multi-tenant in that it provides common functions and infrastructure that are available across multiple tenants supported by the review service. Furthermore, the review service is extensible in that it provides an extensibility point into which tenant-specific functions may be incorporated into the review service. For each one or more of the tenants, the corresponding review target artifact set is distributed such that a tenant-accessible subset of the artifact set is maintained uniquely accessible by the corresponding tenant, and such that a centralized service subset of the review target artifact set is maintained remote from the corresponding tenant.