A DigitalOcean Reserved IP address is a publicly-accessible static IP address that you can assign to a Droplet and then reassign to another Droplet later, as needed. You can implement a failover mechanism with reserved IPs to build a high availability infrastructure.
The DigitalOcean API lets you manage DigitalOcean resources programmatically using conventional HTTP requests. All the functionality available in the DigitalOcean Control Panel is also available through the API.
You can use the API to create, list, and delete reserved IP addresses. You can also manage specific reserved IP addresses using the API, such as assigning or unassigning them.
doctl is a command-line interface for the DigitalOcean API and supports many of the same actions.