# Website speed test: run it free, or from your agent

Lighthouse performance, accessibility, best practices and SEO scores, lab metrics and top fixes for one page.

## Prompt

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.

## What it needs

A page URL

## What comes back

- 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

## Endpoints and providers

- dataforseo: dataforseo-on-page-lighthouse-live-json-ai

## What it costs

The tool on the web page runs live at no cost to you and is limited per hour. The results come from public data through looot. For heavier or repeated use, run the same job from your own looot account: looot bills per call and charges nothing while your agent is idle. The live price comes from the catalog and shows on the web page.

## 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.

## How do I test my website speed?

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.

## Is this website speed test free?

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.

## Is this the same as Google PageSpeed Insights?

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.

## What do LCP, CLS and TBT mean?

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.

## Why do my scores change between runs?

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.

## Does it test the mobile version?

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.

## Why did my test time out?

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.

## How do I run this from my agent?

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.

## Related tools

- /free-tools/website-screenshot
- /free-tools/website-technology-checker
- /free-tools/meta-tag-generator

## Last reviewed

2026-10-14. The price per call is read live from the catalog on the web page.

## Agent skill for this page

https://looot.ai/free-tools/website-speed-test/skill.md sets an agent up for exactly the jobs on this page, with the live price of each, and offers the page's starter task once the user has picked a job and seen the price. The line to give an agent is under "Give this to your agent" below.

## For agents

### Give this to your agent

```text
set up looot for Website speed test - https://looot.ai/free-tools/website-speed-test/skill.md
```