Patch is used to update an existing declaration without sending the whole thing again. For instance, you would use POST to send the whole declaration consisting of virtual servers, pools, profiles etc. However, to add a new pool member you would only need to use a PATCH to update that pool section, not the whole declaration. However, depending on your deployment pipeline, it may be simpler to just update the declaration and redeploy with POST ( and an action of redeploy ). Hopefully that makes some sense. https://clouddocs.f5.com/products/extensions/f5-appsvcs-extension/latest/refguide/as3-api.html