# Instance

An instance is a single virtual server running in the cloud. You choose its size (CPU, memory, storage) from a catalog of instance types and pay for it by the second or hour. Instances are the basic unit of compute in IaaS environments.

Visit the following resources to learn more:

- [@article@What is an Instance In Cloud Computing?](https://aws.amazon.com/what-is/cloud-instances/)
- [@article@What Is an Instance in Cloud Computing? See How It Powers Your Apps](https://visualoneintelligence.com/what-is-an-instance-in-cloud-computing/)
- [@article@Cloud Computing Explained: The Most Important Concepts To Know](https://www.youtube.com/watch?v=ZaA0kNm18pE)