Runtime specification

By default, all our runners have their timezone set to UTC, regardless of their location.

Built-in Node.js modules

  • assert
  • buffer
  • crypto
  • dns
  • fs
  • path
  • querystring
  • readline
  • stream
  • string_decoder
  • timers
  • tls
  • url
  • util
  • zlib

See the built-in module documentation on the official Node.js site:

NPM packages

These are the currently available runtimes and the included external NPM dependencies.

Note: the below libraries are included for setup and teardown scripts as well, with the exclusion of Puppeteer, Playwright and Mocha.


Main updates are Playwright 1.20.2 and Puppeteer 13.7.0 and Node.js 14.x


Main updates are Playwright 1.15.2 and Puppeteer 10.4.0 and Node.js 14.x


Main updates are Playwright 1.12.2, Puppeteer 10.0.0 and Node.js 14.x


This runtime will be available until 07/30/2022. Please update your checks' runtimes and account settings to avoid failures due to automatic change to the next supported runtime.

Main updates are Playwright 1.4.0, Puppeteer 2.0.0 and Node.js 12.x

You can contribute to this documentation by editing this page on Github