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Web Platform Tests

web-platform-tests.org

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Spec score 7.5 #22 of 25 in Cross-Browser Testing Software

What it is

Web Platform Tests is an open-source suite for checking web platform compatibility across browser implementations. Anyone can run tests through the public wpt.live deployment in an internet-enabled browser, or clone the suite for local use on Linux, macOS, or Windows. The suite includes JavaScript API, rendering, crash, WebDriver, and manual tests. Its command-line `wpt` tool runs tests in a selected browser and can produce machine-readable JSON reports and screenshots. It can also save and load expected results for continuous integration and regression tracking. Regularly collected results from a range of browsers are archived at wpt.fyi. Local setup requires Python 3.9 or later and configuration of test domains in the system hosts file. Running tests in multiple browser processes may make results less deterministic and add noise compared with the default single-process mode. The project is free and open source, and documents Windows, macOS, and Linux setup.

Spec sheet

Purpose
Web Platform Tests is a cross-browser test suite for the Web platform, intended to help browser projects check compatibility across implementations.Read 7 Oct 2026 · web-platform-tests.org
Integrations
GitHub is used for issue tracking and test submissions, and pull requests receive automatic labels and reviewer notifications based on directory metadata.Read 7 Oct 2026 · web-platform-tests.org
Security
The project documentation says SSL certificates for HTTPS-enabled domains are obtained through Let’s Encrypt.Read 7 Oct 2026 · web-platform-tests.org
Support
The project directs users to its Matrix chat room and public low-traffic mailing list for questions.Read 7 Oct 2026 · web-platform-tests.org
CI integration
The command-line interface supports saving and loading expected test results for continuous integration and regression tracking.Read 7 Oct 2026 · web-platform-tests.org
CI runs
Contributors with repository write access can trigger full runs in the project’s CI systems, with results submitted to wpt.fyi.Read 7 Oct 2026 · web-platform-tests.org
Command line
The wpt command can run tests in a chosen browser and supports machine-readable JSON reports and screenshots.Read 7 Oct 2026 · web-platform-tests.org
Execution limitation
Running tests in multiple browser processes can make results less deterministic and introduce more noise than the default single-process mode.Read 7 Oct 2026 · web-platform-tests.org
Local execution
Tests can be cloned and run locally, and the project documents Windows, macOS, and Linux setup.Read 7 Oct 2026 · web-platform-tests.org
Public runner
Anyone can run the tests by visiting the public deployment, wpt.live, in an internet-enabled browser.Read 7 Oct 2026 · web-platform-tests.org
Requirements
Local setup requires Python 3.9 or higher and configuration of test domains in the system hosts file.Read 7 Oct 2026 · web-platform-tests.org
Review policy
Test contributions are reviewed publicly, and each pull request needs approval from at least one project collaborator before merging.Read 7 Oct 2026 · web-platform-tests.org
Test archive
wpt.fyi archives test results collected regularly from an array of web browsers.Read 7 Oct 2026 · web-platform-tests.org
Test types
The suite includes JavaScript API tests, rendering tests, crash tests, WebDriver tests, and manual tests.Read 7 Oct 2026 · web-platform-tests.org

Plans and prices

Free Free Cross-browser test suite and public web runner Read 7 Oct 2026 · web-platform-tests.org

Every Web Platform Tests plan and price →

Strong points and limits

Strong points

  • Public runner works in an internet-enabled browser
  • Tests JavaScript APIs, rendering, crashes, and WebDriver
  • Command-line tool supports JSON reports and screenshots
  • Results are archived at wpt.fyi

Limits

  • Local setup requires Python 3.9 or higher
  • Local setup requires test-domain hosts-file configuration
  • Multiple browser processes can make results less deterministic

Who it suits

Web Platform Tests suits browser projects and contributors checking how web features behave across implementations. It also suits teams that need local or continuous-integration test runs and machine-readable results.

Verdict

Web Platform Tests offers public and local cross-browser testing, with command-line reporting and expected-result support for CI. Account for the Python and hosts-file setup requirements, and consider the single-process mode when test consistency matters.

Where Specifiction places it

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