scalable

Scalable is an adjective used to describe systems, processes, or organizations that can grow to handle increased workload or scope without a corresponding drop in performance, reliability, or cost efficiency. Scalability is the capacity of a system to accommodate growth by proportionally increasing resources. A scalable system maintains acceptable performance as demand rises and can be scaled up (more powerful components) or out (more nodes). The term contrasts with rigidity, where growth causes disproportionate degradation.

In computing, scalability is a central design goal for software and infrastructure. Horizontal scaling adds more machines or instances (scale out), often enabled by stateless services, load balancing, and distributed data stores. Vertical scaling increases the capacity of a single machine (scale up) by upgrading CPU, memory, or storage. Key approaches include microservices, containerization, orchestration, caching, sharding, partitioning, and eventual consistency. Real-world limits include network latency, data synchronization, and cost. Scalable systems typically emphasize modularity, automation, observability, and fault tolerance.

In business, scalability refers to the ability of a business model to grow revenue and customers with proportional increases in cost and complexity. Platform-based and cloud-enabled businesses commonly aim for high scalability.

Usage: A product or system described as highly scalable is expected to accommodate growth without a complete redesign. The term is also applied to processes, organizations, and networks.

See also: scalability, elastic computing, load balancing, distributed systems, vertical scaling, horizontal scaling.