# Elastic Load Balancer at a Glance — AWS

Source: https://www.geekswithgeeks.com/en/aws/aws-load-balancer

> Spreading traffic across instances so no single server is overwhelmed.

## What an ELB does

An **Elastic Load Balancer (ELB)** sits in front of your EC2 instances and distributes incoming traffic across healthy ones, so no single instance is overloaded.

## ALB, NLB in brief

**Application Load Balancer (ALB)** understands HTTP — routes by path/host, great for web apps. **Network Load Balancer (NLB)** works at the TCP layer — extremely fast, for raw throughput.

## Pair it with Auto Scaling

An ELB alone doesn't add servers. Pair it with an **Auto Scaling Group** so the fleet grows and shrinks with demand, and the load balancer routes to whatever's currently healthy.

**Quiz:** You need to route requests to different backend services based on the URL path. Which fits best?

- [ ] Network Load Balancer
- [x] Application Load Balancer
- [ ] Security Group

*Answer:* Application Load Balancer. ALB understands HTTP and can route based on path, host, or headers.