Here is the link for SRM API: Site Recovery Manager API Documentation
And about vSphere Replication, see: vSphere Replication FAQ (2005776) | VMware KB
VMware vSphere Replication Standalone VS. Site Recovery Manager with vSphere Replication.
- VMware vSphere Replication Standalone is used for data replication while Site Recovery Manager is for automation.
- With vSphere Replication Standalone, virtual machines can only be recovered one at a time. There is no API available. If there is a need to recover multiple virtual machines at the same time, this is not possible with the vSphere Replication standalone unless using it with Site Recovery Manager.
- There are limitations on customizing virtual machines that are recovered using the vSphere Replication Standalone. The virtual machine needs to be recovered first. Then once done, you are now able to customize the VM (eg. IP, network configuration etc.)