Single droplets are a single point of failure and have a limited availability. You can take actions to mitigate this SPOF like running multiple droplets and distributing requests by adding all of these droplets to your DNS configuration also known as DNS round robin.

Another solution is too pay Digital Ocean to provide network endpoints that are more available and allow you to provide a higher availability for your application. Because DO works on different level of abstraction they have more possibilities to provide this availability.