Requests to change attributes of servers or other computing resources can be validated by a veto service. For example, the veto service can receive requests to register for notification of changes to an attribute for a server, send a notification of a pending change to the attribute to each of a plurality of services, determine a response to the notification for each service, and based on the responses decide whether to allow or deny the pending change to the attribute. The responses from the notified services can be received responses or default responses.