WebPageTest vs Yellow Lab Tools (2026): which should you pick?

Pick WebPageTest if

• Fits if you need to see how a page loads in a given browser from a given city
• Works for checking a fix's effect side by side before you change the site, on Pro

Look elsewhere if

• Watch out: every page load counts as a run, so 5 runs with repeat views use 10 of your 150
• Tight if you stay on Starter, with 3 runs per test and no scheduled tests, alerts, API or Experiments
• Not for you if you want to try Pro first, as there's no free trial
• Too light for bigger teams, as a Pro account holds up to 5 members

Pick Yellow Lab Tools if

• Fits if you're a front-end developer tracing what makes one page heavy or slow
• Works for testing pages on localhost or an intranet through a private copy

Look elsewhere if

• Skip it if you need a whole site checked, as each run tests one page address
• Not for you if you want ongoing monitoring, since no scheduled tests are described
• Watch out: the public site processes one run at a time, so a test can wait behind others
• Tight if you self-host on Windows, which the author says is untested; Linux and macOS are documented
• Watch out: under GPL-2.0, changes to a hosted copy's code must be published under the same license

WebPageTest

• Every page load counts as a test run: 5 runs with first and repeat views use 10 of the monthly allowance.
• Starter allows 150 runs a month and 3 runs per test; scheduled tests, alerts, the API and Experiments need Pro.
• There is no free trial of Pro, and a Pro account holds up to 5 team members.
• The webpagetest.org site answered with a bot check; prices were read on LogicMonitor's WebPageTest pricing page.

Yellow Lab Tools

• Each run tests one page address; the documentation describes no site-wide crawl or scheduled monitoring.
• The public instance queues runs and processes one at a time, so a test can wait behind others.
• Self-hosting needs Node.js and is documented for Linux and macOS; the author says Windows is untested.
• Under the GPL-2.0 license, changes to the code of a hosted copy must be published under the same license.

WebPageTest

Real-browser tests

Test in Chrome (stable, beta and canary), Firefox (stable, beta and ESR), Edge and Brave, on desktop or mobile, over connection speeds from 3G to fiber.

Global test locations

Starter runs tests from 30 locations across six continents; Pro adds more, including many more US cities.

Lighthouse, filmstrip and video

Each test can include a Lighthouse run, a filmstrip and a video of the page loading, on every plan.

Opportunities

Recommendations grouped under quickness, usability and resilience, with tips on what to fix. Available to all users.

Experiments

Pro runs a proposed optimization side by side with a control test in a sandbox, so its effect shows without changing the site's code.

Scheduled tests and alerts

Pro schedules tests, sends custom alerts, builds Smartboards dashboards and keeps 13 months of history, with API, private and bulk testing.

Yellow Lab Tools

Scored page audit

Gives a global score out of 100 and a grade per rule, grouped as network, images, DOM, JavaScript, jQuery, CSS, web fonts and server config.

Offenders and score gain

Each rule lists the files, selectors or functions at fault and says how many points the global score would gain if it were fixed.

Device and access settings

Simulates a phone, tablet or desktop, and can send cookies, basic HTTP login details or a proxy, or block and allow chosen domains.

Public API

A REST API on yellowlab.tools queues runs, reports their status and returns the full JSON result or parts of it, with CORS allowed.

Command line and Node module

Installed from npm, the yellowlabtools command tests a page and prints the result as JSON or XML, with an optional screenshot.

Private server

The server code can be installed on your own machine or run from a community Docker image, for testing pages on localhost or an intranet.

WebPageTest

• Starter$0

  150 test runs a month, up to 3 runs per test, 30 locations, Lighthouse, Opportunities and 60 days of test history.

• Pro 1,000 runs$180

  per year for 1,000 test runs a month ($18.75 billed monthly)

  Scheduled tests, alerts, Smartboards, API access, Experiments, private and bulk tests, more locations, 13 months of history and up to 5 users.

• Pro 5,000 runs$840

  per year for 5,000 test runs a month ($87.50 billed monthly)

  The same Pro features with a larger monthly allowance of test runs.

• Pro 10,000 runs$1,620

  per year for 10,000 test runs a month ($168.75 billed monthly)

  The same Pro features with 10,000 test runs a month.

• Pro 20,000 runs$3,000

  per year for 20,000 test runs a month ($312.50 billed monthly)

  The largest listed Pro allowance, with 20,000 test runs a month.

Yellow Lab Tools

• Free$0

  The public instance at yellowlab.tools, its REST API, the npm command-line tool and the open-source server.

WebPageTest

• Annual discount

  Save 20% with annual billing

  Pro with 1,000 runs a month is $180 a year billed annually, against $18.75 a month billed monthly; the pricing page lists a 20% saving.

Yellow Lab Tools

No public discounts listed.