A modern load testing tool, using Go and JavaScript

"like unit testing, for performance"

k6 is a modern load testing tool, building on Load Impact's years of experience. It provides a clean, approachable JavaScript scripting API, distributed and cloud execution, and orchestration via a REST API.

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HTTP/2.0 is the latest version of the HTTP protocol and introduces some major improvements compared to its predecessor. Chiefly of which is the introduction of a binary wire protocol with multiplexed streams over a single TCP connection. This solves a long-standing performance issue with HTTP/1.1, head-of-line blocking. Well, it at least partially solves it, since you still have TCP congestion control mechanisms interfering with the intended independent nature of the multiplexed streams in cases of lost/dropped packets and retransmission/reassembly. The full solution is to run HTTP/2.0 over UDP, which is what Google implemented with QUIC.

Some other features of HTTP/2.0:

  • Builtin compression of HTTP headers
  • Server push
  • Pipelining of requests
  • Prioritization of requests

Load testing HTTP/2 with k6

When you make HTTP requests in k6 it will automatically upgrade the connection to HTTP/2.0 if the server supports it, just like your web browser would. You can check what protocol was used for a particular request by looking at the proto property of the response object.

import http from "k6/http";
import { check, sleep } from "k6";

export default function() {
  let res = http.get("https://www.bbc.co.uk/");
  check(res, {
    "protocol is HTTP/2": (r) => r.proto === 'HTTP/2.0'

For more information on what values the r.proto field can have, check out:


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