DigitalOcean floating IPs are publicly-accessible static IP addresses that you can assign to Droplets and instantly remap between other Droplets in the same datacenter. Implement a failover mechanism with floating 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.
doctl is a command-line interface for the DigitalOcean API and supports many of the same actions.
doctl documentation on floating IPs for more information.