A load balancer is a device that acts as a reverse proxy and distributes network or application traffic across a number of servers. Load balancers are used to increase capacity (concurrent users) and reliability of applications. They improve the overall performance of applications by decreasing the burden on servers associated with managing and maintaining application and network sessions, as well as by performing application-specific tasks. As an organization meets the demand for its applications, the load balancer decides which servers can handle that traffic. This maintains a good user experience.

Load balancers manage the flow of information between the server and an endpoint device (PC, laptop, tablet, or smartphone). The server could be on-premises, in a data center or the public cloud. The server can also be physical or virtualized. The load balancer helps servers move data efficiently, optimizes the use of application delivery resources and prevents server overloads. Load balancers conduct continuous health checks on servers to ensure they can handle requests. If necessary, the load balancer removes unhealthy servers from the pool until they are restored. Some load balancers even trigger the creation of new virtualized application servers to cope with increased demand.

Traditionally, load balancers consist of a hardware appliance. Yet they are increasingly becoming software-defined. This is why load balancers are an essential part of an organization’s digital strategy.