Technology Fundamentals

Scalability

Definition

Scalability is the property of a system to handle a growing amount of work by adding resources to the system. In an economic context, a scalable business model implies that a company can increase sales given increased resources.

Why It Matters

For any growing application or service, scalability is crucial. A scalable system can handle sudden spikes in traffic or data volume without crashing or slowing down, ensuring a good user experience.

Contextual Example

An e-commerce site must be scalable to handle the massive traffic increase on Black Friday. This is often achieved by adding more web servers (horizontal scaling) or upgrading to more powerful servers (vertical scaling).

Common Misunderstandings

  • Horizontal scaling (scaling out) means adding more machines to your pool of resources. Vertical scaling (scaling up) means adding more power (CPU, RAM) to an existing machine.
  • Scalability is not the same as performance. A system can be fast with one user but not be scalable enough to handle a thousand users.

Related Terms

Last Updated: December 17, 2025