This content originally appeared on DEV Community and was authored by Gimhan Rajapaksha
When you’re working on scalable systems, three terms often pop up: Load Balancer, Reverse Proxy, and API Gateway.
At first, they might sound interchangeable since they all sit between the client and the backend servers. But in reality, each plays a unique role in modern system architecture.
Let’s break them down with simple explanations and comparisons.
1. Load Balancer
Main Purpose: Distributes incoming traffic across multiple servers.
- Why it matters: Ensures no single server gets overwhelmed, improves fault tolerance, and boosts availability.
- How it works: It checks the health of servers and routes requests to the available ones.
- Extra features: Can do session persistence, round-robin scheduling, and weighted distribution.
Think of it like traffic police directing cars into different open lanes so that traffic flows smoothly.
2. Reverse Proxy
Main Purpose: Acts as an intermediary between clients and backend servers.
- Why it matters: Hides the server’s identity and provides an extra security layer.
- How it works: Accepts the request on behalf of the server, processes it (like SSL termination), and forwards it internally.
- Extra features: Caching, compression, centralized logging, security filtering.
Think of it as a receptionist at the front desk — you never talk directly to the people inside; the receptionist filters and forwards your request.
3. API Gateway
Main Purpose: A specialized proxy designed for microservices architectures.
- Why it matters: Manages APIs and routes requests to the correct microservice.
- How it works: Handles cross-cutting concerns like authentication, rate limiting, monitoring, and even API versioning.
- Extra features: Request aggregation, transformations, policy enforcement.
Think of it as a smart security gate that not only lets you in but also checks your ID, enforces rules, and guides you to the right department.
Quick Comparison
| Feature | Load Balancer | Reverse Proxy | API Gateway |
|---|---|---|---|
| Traffic distribution | |
 |
(for APIs) |
| SSL termination | |
|
|
| Caching | |
|
Sometimes |
| Authentication | |
|
|
| Best for | Scaling apps | Hiding servers | Microservices |
How They Work Together
These tools aren’t mutually exclusive. In many modern systems, you’ll see them combined:
- A Load Balancer distributes traffic to multiple nodes.
- A Reverse Proxy adds security and caching in front of those nodes.
- An API Gateway manages communication across microservices.
Together, they provide scalability, security, and manageability in distributed architectures.
Final Thoughts
If you’re building or maintaining scalable systems, it’s worth understanding the unique role of each:
- Load Balancer = distributes traffic efficiently
- Reverse Proxy = hides and protects backend servers
- API Gateway = orchestrates APIs in microservices
This content originally appeared on DEV Community and was authored by Gimhan Rajapaksha