This benchmarks a websocket server intended as a simple but very active chat room.

First, start the server. By default, it will wait for 32 clients which the client script will handle.

Run in Bun (Bun.serve):

bun ./chat-server.bun.js

Run in Node ("ws" package):

node ./chat-server.node.mjs

Run in Deno (Deno.serve):

deno run -A ./chat-server.deno.mjs

Then, run the client script. By default, it will connect 32 clients. This client script can run in Bun, Node, or Deno

node ./chat-client.mjs

The client script loops through a list of messages for each connected client and sends a message.

For example, when the client sends "foo", the server sends back "John: foo" so that all members of the chatroom receive the message.

The client script waits until it receives all the messages for each client before sending the next batch of messages.

A single client process can become the bottleneck for fast servers. To spread the 32 clients across several processes, start each one with CLIENTS_COUNT set to its share and TOTAL_CLIENTS set to the total the server was started with, so every process expects the echoes of all senders:

CLIENTS_COUNT=32 bun ./chat-server.bun.js &
for i in 1 2 3 4; do CLIENTS_COUNT=8 TOTAL_CLIENTS=32 bun ./chat-client.mjs & done; wait

This project was created using bun init in bun v0.2.1. Bun is a fast all-in-one JavaScript runtime.