Load Balancer
Distributes incoming traffic across multiple servers so no single server gets overwhelmed. Like a traffic cop directing cars to different lanes.
What is Load Balancer?
Distributes incoming traffic across multiple servers so no single server gets overwhelmed. Like a traffic cop directing cars to different lanes.
Load Balancer is a foundational concept that sits in the Load Balancing & Proxies area of system design. Engineers reach for it whenever they need to reason about real-world trade-offs in that space — not just for textbook correctness, but because real production systems at companies like Netflix, Amazon, and Google make these decisions every day.
If you want to go deeper than this definition — with diagrams, code, and a quiz to lock it in — work through the "Load Balancer" lesson linked below. It walks through the why, the mechanism, the trade-offs, and how the giants actually use it in production.
Learn Load Balancer in depth
Full interactive lesson with diagrams, code examples, real-world references, and a quiz.
Open the Load Balancer lessonRelated lessons
Lessons that touch on Load Balancer as part of a larger topic.
Load Balancer Failover
Automatic traffic rerouting when backends fail, health check integration with load balancers
advanced · reliability resilience
Load Balancer Algorithms
How load balancers decide which server gets the next request. Round Robin, Weighted, Least Connections, IP Hash, and more
foundation · load balancing proxies
See also
Related glossary terms you might want to look up next.
Reverse Proxy
A server that sits in front of your backend servers and forwards client requests to them. Handles SSL termination, caching, and load balancing.
Horizontal Scaling
Adding more machines to handle increased load (scaling out). Like opening more checkout lanes instead of making one cashier faster.
API Gateway
A single entry point for all client requests that routes them to the appropriate microservice. Handles auth, rate limiting, and request transformation.