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Docs / Runtimes / Specs
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Runtime specification

On this page

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

Resource limitations

Each Browser and Multistep check can use up to 2.9 GiB of memory and 2 vCPU cores. This limit applies to all processes spawned by the check, including the browser, the test framework, and the test code itself. The limit is enforced by the runner and is not configurable.

When the memory limit is exceeded, the check will automatically fail with a relevant error message, for example: Your check has reached the maximum memory usage of 2.9 GiB.

Built-in Node.js modules

The following standard Node modules are included and can be used as normal, e.g.

import * as path from 'path'
  • assert
  • buffer
  • crypto
  • dns
  • fs (partial, we have restricted some file system operations for security reasons)
  • path
  • querystring
  • readline
  • stream
  • string_decoder
  • timers
  • tls
  • url
  • util
  • zlib

See the built-in module documentation on the official Node.js site (please see below which runtime includes what NodeJS version):

NPM packages

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

The packages below are included for setup and teardown scripts as well, with the exclusion of Playwright and mocha. mocha is deprecated. Please use @playwright/test as a test framework instead.

2024.09

Node.js Version: v18.20.3

The main update is Playwright 1.48.2. The Node.js version is v18.20.3. New dependencies are @clerk/testing, mailosaur, gaxios, @kubernetes/client-node and mysql.

2024.02

Node.js Version: v18.20.3

The main update is Playwright 1.42.1. The Node.js version is v18.20.3. New dependencies are @opentelemetry/exporter-metrics-otlp-grpc, @opentelemetry/sdk-metrics, chai-json-schema, pdf2json, protobufjs, long and the nice-grpc family.

2023.09

Node.js Version: v18.20.3

The main updates are Playwright 1.38.1 and the addition of ethers 6.7.1, prisma 5.1.1, zod 3.22.2, @t3-oss/env-nextjs 0.6.1 and @xmldom/xmldom 0.8.10. The Node.js version is v18.20.3.

2023.02

Node.js Version: v16.20.2

The main updates are Playwright 1.32.1, faker 7.6.0 and the addition of date-fns 2.29.3 and ws 8.13.0. We are dropping support for Mocha.

2022.10

Node.js Version: v16.20.2

The main updates are Playwright 1.28.0, Node.js v16.20.2 and Typescript support. We are dropping support for Puppeteer.

Last updated on December 13, 2024. You can contribute to this documentation by editing this page on Github