Website speed testSEO

Website speed test. Lighthouse scores and fixes.

Paste a URL and get one Lighthouse lab run on desktop: four category scores, LCP, CLS, TBT, FCP and Speed Index, and the five fixes with the biggest estimated saving. Our test runs took 13 to 54 seconds, and this page waits up to 55, so a very heavy page can still time out.

1 provider in the catalog

Live price

reading live price

A page URL
you give it
1
providers
per call
billing

Try it now

Run website speed test here

Each run costs you nothing and is limited per hour. The results come from public data through looot. Heavier or repeated use belongs on your own looot account.

A public page, tested on desktop. A run can take up to a minute.

Each run is free to you and limited per hour. The data is public. Powered by looot. Run it on your own looot account for heavier or repeated use.

Run it from your agent

Copy one prompt, give it to your agent.

Fill in the placeholder, paste it, and the agent runs the same job on your looot account and shows the cost. It can take a whole list, which the box above does not.

  • You give it: a page url.
  • Billed per call, nothing while your agent is idle.
  • The agent shows the price before it calls.
Prompt: Website speed test
Use looot to run a Lighthouse test on these pages: [paste the URLs]. 1. Set up https://looot.ai/skill.md. 2. Search the catalog for a Lighthouse endpoint and check its price before you call. 3. Run it once per URL. 4. Return a table with each URL, its four category scores, LCP, CLS and TBT, and the three biggest fixes, worst page first.

Give this to your agent
Setup command
set up looot for Website speed test - https://looot.ai/free-tools/website-speed-test/skill.md

What comes back

What your agent gets from website speed test

Field names as the providers return them. The exact set varies by endpoint, and your agent reads it from the catalog.

  • performance, accessibility, best practices and SEO scores
  • LCP, CLS, TBT, FCP and Speed Index
  • the top five opportunities with estimated savings
  • Lighthouse version and test time

Providers

Who can do this job today

Your agent picks the endpoint. These providers offer one right now, with the live price of their cheapest.

Use it for

What people do with website speed test

  • Before a launch

    Check a new page's scores before you send traffic to it.

  • SEO audits

    Get the lab metrics behind Core Web Vitals for a client page.

  • Find slow pages

    Test your key pages and fix the slowest one first.

  • Many pages

    Hand your agent a list of URLs and get every score in one table.

Set up once

Three steps. Your agent does the rest.

Keep going

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FAQ

Questions about website speed test

Paste the page URL or the domain in the box at the top of this page and press the button. You get one Lighthouse run with scores, metrics and the biggest fixes.

Yes. It costs you nothing and needs no account, and it is limited per hour. For many pages, your agent runs the same test on your own looot account.

Both run Lighthouse, Google's open source page audit. This tool runs one lab test on desktop through DataForSEO. PageSpeed Insights also shows field data from real Chrome users, which this tool does not.

Largest Contentful Paint is when the main content shows. Cumulative Layout Shift measures how much the page jumps while it loads. Total Blocking Time is how long scripts block clicks and typing. Lower is better for all three.

Lab tests vary with the network, the server load and third party scripts. Run the test two or three times and look at the trend, not one number.

No. The tool on this page runs the desktop test. Lighthouse slows the network and CPU for its mobile run, so mobile scores are usually lower.

Lighthouse loads the whole page in a real browser. In our runs that took 13 to 54 seconds, and this page waits up to 55. Try a lighter page on the same site, or copy the prompt above: your agent can wait longer.

Copy the prompt above into Claude, Cursor or any agent with the looot skill. It finds the Lighthouse endpoint, shows the price and returns one table for all your pages.
For agents
tool
Website speed test
category
SEO
input
A page URL
output
performance, accessibility, best practices and SEO scores, LCP, CLS, TBT, FCP and Speed Index, the top five opportunities with estimated savings, Lighthouse version and test time
endpoint
dataforseo: dataforseo-on-page-lighthouse-live-json-ai
price
per call, read live from the catalog on the web page
web tool
runs live on the page, free to the visitor and limited per hour
schedule
on demand
setup
https://looot.ai/free-tools/website-speed-test/skill.md
llms.txt
https://looot.ai/llms.txt
updated
2026-10-14
markdown /free-tools/website-speed-test.md

Run website speed test from your own agent.

The box on this page is limited per hour. Start your workspace, top up, and paste the prompt into the agent you already use for lists and repeated runs.

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