Alternatives to Yellow Lab Tools
An open-source tool that audits a webpage for performance and front-end code quality issues. The listings below can replace it for an important use case. Each note says what changes if you switch.
The original
Yellow Lab Tools
An open-source tool that audits a webpage for performance and front-end code quality issues.
Replacements
Listings that take over the same core job as Yellow Lab Tools.
WebPageTest
An online website performance tester with waterfall charts, filmstrips, multiple locations and throttled connections.
WebPageTest gives detailed waterfalls, filmstrips and throttled tests from multiple locations, but is not open source and puts some features behind paid plans.
GTmetrix
An online page speed tester with waterfall charts, Core Web Vitals, scheduled monitoring and alerts.
GTmetrix adds Core Web Vitals, 25 test regions, scheduled monitoring and an API, but is hosted only and many options need an account.
PageSpeed Insights
Google's free web tool that reports Core Web Vitals and Lighthouse results for any URL.
PageSpeed Insights is Google's hosted free tool with field and lab data and Lighthouse suggestions, but cannot be self-hosted for internal sites.
DebugBear
A web performance testing and monitoring service with a free Core Web Vitals speed test.
DebugBear combines lab tests with real-user Core Web Vitals and third-party impact, with continuous monitoring on a paid plan.
Experte Page Speed Test
A free bulk page speed test that runs PageSpeed Insights metrics across many URLs at once.
Experte Page Speed Test runs PageSpeed Insights metrics across up to 500 URLs at once, without code quality analysis or self-hosting.
Uptrends Website Speed Test
A free online website speed test with waterfall reports, Core Web Vitals and filmstrip screenshots.
Uptrends Website Speed Test shows waterfalls, filmstrips and third-party timings in Chrome or Edge, as a hosted freemium tool.
sitespeed.io
An open-source tool for measuring, analysing and monitoring the performance of web pages.
sitespeed.io is also open source and runs on your own infrastructure, adding video, HAR waterfalls and long-term monitoring via Graphite or InfluxDB, but lacks a hosted online tool.
Unlighthouse
Open-source command-line tool that runs Google Lighthouse on every page of a site in parallel.
Unlighthouse is an open-source MIT-licensed CLI that runs Lighthouse on every page of a site in parallel, requiring Node 22 or later.
Also worth comparing
These listings name Yellow Lab Tools as their own alternative, so the relationship runs both ways.
KeyCDN Website Speed Test
A free full-page speed test with a waterfall breakdown, run from one of 10 global locations.
Yellow Lab Tools is open source under GPL-2.0, audits front-end code quality as well as speed, and can be self-hosted for internal sites.
Lighthouse
Automated audits for performance, accessibility, SEO and best practices.
Yellow Lab Tools audits page weight and front-end code quality with detailed explanations and can be self-hosted, but does not cover accessibility or SEO and development has slowed.
Lighthouse CI
A set of tools that runs Lighthouse audits on every commit and tracks results over time.
Yellow Lab Tools is a GPL-2.0 tool with a CLI and API that audits front-end code quality and page weight, though its development has slowed since early 2024.
webhint
A customizable linting tool that checks websites for accessibility, speed, compatibility and security problems.
Yellow Lab Tools focuses on performance and front-end code quality under GPL-2.0, as an online tool, CLI and self-hostable service, though development has slowed.
Similar software
Related functionality, not a direct replacement.
Request Map Generator
A web tool that draws a node map of every request a page makes, including third parties.
Treo
A web dashboard for tracking Core Web Vitals across sites using Chrome UX Report and Lighthouse data.
Nu Html Checker
The W3C's online checker that tests HTML documents against current HTML conformance rules.
W3C CSS Validation Service
The W3C's free service for checking CSS and style sheets in HTML documents.
