Vertical scaling, also known as "scaling up," refers to the process of increasing the capacity of a single server or machine. This can be achieved by adding more resources, such as CPU, RAM, or storage, to enhance its performance. Vertical scaling is often simpler to implement since it involves upgrading existing hardware rather than distributing workloads across multiple systems. However, vertical scaling has its limitations. There is a maximum capacity that a single machine can handle, and once that limit is reached, further scaling becomes impossible. This contrasts with horizontal scaling, where additional machines are added to distribute the load, allowing for greater flexibility and scalability in handling increased demand.