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Concepts

Socat as a Lightweight Load Balancer

Andrios Robert

• 1 min read

The network was choking. Traffic poured in faster than the application could breathe. The answer was a load balancer. The weapon was Socat.

What is Socat?
Socat is a command-line utility that creates bidirectional data channels. It’s simple, fast, and flexible. It can handle TCP, UDP, and even UNIX sockets. For load balancing, it can forward connections to multiple backend servers, splitting traffic without heavy dependencies.

Why use Socat as a load balancer?
Socat runs almost anywhere. No bloated frameworks. No web UI you never open. You configure it once, and it pushes packets exactly where they need to go. It’s perfect for temporary setups, development environments, container testing, or minimalistic production use cases.

Basic Socat Load Balancer Example
The simplest TCP load balancer with Socat might look like this:

socat TCP4-LISTEN:8080,fork \
 TCP4:backend1.example.com:80 \
 TCP4:backend2.example.com:80

This example listens on port 8080 and forks each incoming connection. The fork allows multiple clients to connect at once. Each connection gets proxied to backend1 or backend2 according to your config. In practice, you can run multiple socat processes to distribute load in round-robin or custom patterns.

Advanced Configurations
You can chain Socat commands, combine it with DNS-based load balancing, or wrap it in shell scripts for dynamic connection targeting. Examples include:

  • Balancing across containers in a local Docker network.
  • Splitting UDP traffic to different microservices.
  • Using UNIX sockets as upstream targets for better performance in internal clusters.

Pros and Cons
Pros:

  • Lightweight
  • Minimal dependencies
  • Runs anywhere with a shell

Cons:

  • No built-in health checks
  • Simple connection splitting, no advanced algorithms like least connections or weighted routing

You can offset limitations by integrating Socat with external monitoring tools or scripts that restart processes when targets go down.

Socat may not replace HAProxy or NGINX for high-volume production needs, but for quick load balancing, prototyping, or internal routing, it delivers immediate results.

If you want to see a load balancer built on Socat go live in minutes, check out hoop.dev and run it yourself.