A load balancer is a tool that spreads incoming traffic across several servers so no single one gets overloaded. It helps keep websites fast and available even when lots of people are using them.

How it works

When a request comes in, it first hits the load balancer instead of the server directly. The load balancer checks which server is least busy (or healthiest) and sends the request there. If one server goes down, it stops sending traffic to that one and uses the others.

Analogy

Think of a busy restaurant with many chefs. The head waiter (the load balancer) takes each order and gives it to a chef who's free. If one chef is sick, the waiter just skips them. This way, customers get their food quickly and no single chef is overwhelmed.