Hello, I will soon merge the following patches that introduce a new way to specify the contracts of the RESTAPI: restapi: Introduce metamodel https://gerrit.ovirt.org/45852 restapi: Use metamodel https://gerrit.ovirt.org/46478 restapi: Generate JAX-RS interfaces from model https://gerrit.ovirt.org/47337 These patches introduce a new "metamodel" concept, and move the current specification of the RESTAPI based on XML schema and JAX-RS interfaces to a new "model" built on the new metamodel. What does this mean for you in practical terms? Currently when you want to introduce or modify one of the data types used by the RESTAPI you start by modifying the XML schema. Once the patches are merged the XML schema will never be touched, as it will be automatically generated from the "model". For example, imagine that you need to add a new "color" attribute to the "VM" entity. To do so with the new model you will have to modify the following file, which is the specification of the "Vm" entity, written as a Java interface: https://gerrit.ovirt.org/#/c/46478/16/backend/manager/modules/restapi/mod... In that interface you will have to add a line like this: String color(); Note that this Java interface is just the specification of the entity, it won't be used at all during runtime. Instead of that the XML schema will be generated from it, and then Java will be generated from the XML schema, as we do today (this will change in the future, but not yet). Same for the services. If you want to add a new "paint" action to the "Vm" resource then you won't modify the JAX-RS interfaces, instead of that you will modify the following file, which is the specification of the "Vm" service, written as a Java interface: https://gerrit.ovirt.org/#/c/47337/6/backend/manager/modules/restapi/mode... In that interface you will need to add a sub-interface representing the action: interface Paint { } The JAX-RS interface will be generated from that. Currently these sub-interfaces are empty. In the future they will contain the specifications of the parameters (currently in the rsdl_metadata.yml file). These changes will currently affect only the specification of the RESTAPI, not the implementation, so in in the "Backend*Resource" classes things won't change yet. If you have doubts, please let me know. Regards, Juan Hernandez -- Dirección Comercial: C/Jose Bardasano Baos, 9, Edif. Gorbea 3, planta 3ºD, 28016 Madrid, Spain Inscrita en el Reg. Mercantil de Madrid – C.I.F. B82657941 - Red Hat S.L.