autocannon

8.0.0 verified Sat Apr 25 auth: no javascript

An HTTP/1.1 benchmarking tool for Node.js, designed to be fast and easy to use. Current stable version is 8.0.0, released in late 2021. It supports HTTP pipelining, HTTPS, and can produce more load than wrk or wrk2. It offers both a command-line interface and a programmatic API, with features like warm-up, worker threads, HAR file replay, and custom request bodies. The project is actively maintained by the Node.js community.

Common errors

error Error [ERR_REQUIRE_ESM]: require() of ES Module /path/to/autocannon/index.js from /path/to/your.js not supported. ↓

cause Using require() to import autocannon v8 which is ESM-only.

fix

Replace require('autocannon') with import autocannon from 'autocannon' or use dynamic import().

error autocannon is not a function ↓

cause Importing autocannon incorrectly; e.g., importing named export instead of default.

fix

Use import autocannon from 'autocannon' (default import).

error connect ECONNREFUSED 127.0.0.1:3000 ↓

cause Target server is not running or port is wrong.

fix

Ensure the server is running on the specified port; check URL and port.

Warnings

breaking autocannon v8 dropped CommonJS support; requires ESM imports. ↓

fix Update imports to use ESM syntax; do not use require().

deprecated The 'printResult' function is deprecated in favor of 'autocannon.print'. In v8, 'printResult' may be removed. ↓

fix Replace autocannon.printResult(output, result) with autocannon.print(output, result).

gotcha When using '--workers', the callback in the programmatic API is not called; results are only available via track or event listeners. ↓

fix Use autocannon.track() or listen for 'done' event on the instance.

gotcha Setting both 'amount' and 'duration' will cause 'duration' to be ignored. ↓

fix Use only one of 'amount' or 'duration' at a time.

gotcha When using a custom 'requestIterator', the 'requests' option inside the iterator must be an array of objects with 'method', 'path', etc., not just strings. ↓

fix Ensure the 'requests' array contains objects with 'method', 'path', 'headers', 'body' as needed.

Install

npm install autocannon

yarn add autocannon

pnpm add autocannon

Imports

default

wrong

const autocannon = require('autocannon')

correct

import autocannon from 'autocannon'

ESM-only since v8; CJS deprecation warning since v7.

autocannon.track

wrong

import { track } from 'autocannon'; track(instance)

correct

import autocannon from 'autocannon'; autocannon.track(instance)

track is a static method on the default export, not a named export.

Result type

wrong

import { Result } from 'autocannon'

correct

import autocannon from 'autocannon'; const result: autocannon.Result = ...

Result is exported as a type via the default export's namespace, not a named export.

Quickstart

Runs a 10-second benchmark with 10 concurrent connections against a local server and prints progress to console.

import autocannon from 'autocannon';

const instance = autocannon({
  url: 'http://localhost:3000',
  connections: 10,
  duration: 10,
}, (err, result) => {
  if (err) {
    console.error(err);
    return;
  }
  console.log(result);
});

autocannon.track(instance);