netsu

iperf3-compatible network speed test — TypeScript library and CLI.

• Speaks the iperf3 wire protocol: test against an official iperf3 -s, or point iperf3 -c at a netsu server.
• Adds a WebSocket mode (netsu ↔ netsu only) that traverses HTTP proxies.
• TCP / UDP / WS × upload / reverse, parallel streams, interval reports, UDP jitter & loss, --json output.

CLI

# server
npx netsu server -p 5201            # tcp+udp, iperf3-compatible
npx netsu server -p 5201 --ws       # websocket mode

# client
npx netsu client <host> -t 5                 # tcp upload
npx netsu client <host> -R                   # reverse: server sends
npx netsu client <host> -u -b 10M            # udp at 10 Mbit/s
npx netsu client <host> --ws -P 4            # websocket, 4 streams
npx netsu client <host> --json               # machine-readable output

Works against official iperf3 either way:

iperf3 -s -p 5201            # official server …
npx netsu client localhost   # … netsu client

npx netsu server -p 5201     # netsu server …
iperf3 -c localhost          # … official client

Library

import { runClient, startServer } from "netsu";

const server = await startServer({ port: 5201 });

const result = await runClient("127.0.0.1", {
  port: 5201,
  duration: 5,
  reverse: false,
  parallel: 2,
  onInterval: (r) => console.log(r.bitsPerSecond),
});
console.log(result.sendBitsPerSecond, result.receiveBitsPerSecond);

await server.close();

The wire protocol is documented in PROTOCOL.md.