A website audit anyone can understand.

sitelens checks performance, SEO, accessibility and security, then tells you in plain language what to fix and why.

Prefer the terminal?

$ npx sitelens https://yourwebsite.com --lang en

Cover of a sample sitelens report for przykladowa-firma.pl with an overall score of 71 out of 100 — Sample audit of przykladowa-firma.pl (report in Polish)

What sitelens checks

Four areas that decide whether customers find your site, wait for it to load and can use it without trouble. Every result comes from a specific test.

Performance

How fast the page appears on a phone and whether anything jumps around.

Main content loaded

4.1 s

0 s2.5 s4 s5 s

Good: under 2.5 s

Time until the main content loads
Layout shifts and response to taps
Image size and format

SEO

Whether Google understands the site and can show it in search results.

przykladowa-firma.pl › offer

Offer | Sample Company

No description – Google will show a random piece of text

Title and description of every page
Sitemap and robots.txt
Broken links and redirects

Security

Whether the connection is encrypted and the server protects visitors.

HTTPS and certificatevalid until 14 Mar 2027

Strict-Transport-Securitypresent

Content-Security-Policymissing

Files over http://2

HTTPS and certificate
Files loaded without encryption
Security headers

A report you can pass on

Six A4 pages. First what to start with, then every problem in turn, and technical details for your developer at the end.

Page 1 of 6

Cover

Overall score, scores for the four areas and a one-sentence summary.

Download the sample reportPDF, 0.4 MB, in Polish

No jargon

We describe every problem so the site owner knows what to do and the developer knows where to look.

A typical tool

Largest Contentful Paint exceeds threshold (4.1 s)

sitelens

The page loads too slowly on phones. The main content appears after 4.1 s, and a good result is under 2.5 s.

Who fixes it: Developer. Effort: Medium.

Metric names and technical details are in the report appendix.

Two ways to the same report

In your browser with nothing to install, or with one command in the terminal.

In your browser

Paste the website address.
Wait for the audit to finish.
Download the PDF report.

Check a website online

In the terminal

Install Node.js 22.19 or newer, or sitelens itself with one command from the guide.
Run the command and pick the language, address and mode with the arrow keys:
$ npx sitelens
Open report.pdf.

Step-by-step guide for macOS and Windows

In GitHub Actions

Add the audit to every deployment. The --fail-under option stops the build when the score drops below your threshold, and the report is saved as an artifact.

.github/workflows/sitelens.yml

name: sitelens
on:
  push:
    branches: [main]
  pull_request:
jobs:
  audit:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/setup-node@v7
        with:
          node-version: 24
      - run: npx --yes sitelens https://yourwebsite.com --lang en --fail-under 80 --out report.pdf
      - uses: actions/upload-artifact@v7
        if: always()
        with:
          name: sitelens-report
          path: report.pdf

Open source under the MIT license

See how every score is calculated, suggest an idea or add your own check. Each one has an advice card written in plain language.

View the code on GitHub Suggest an idea

Sample advice cardcards/seo/meta-description.yaml

id: seo/meta-description
priority: important
whoFixes: owner
effort: small
en:
  title: "{count} of {total} pages have no description for Google"
  whatIsWrong: >
    The pages have no short description, which Google
    shows under the title in search results.
  whyItMatters: >
    Without one, Google picks a random piece of text.
  howToFix:
    - Open the page in your CMS and find the “Description” field.
    - Write one or two sentences, up to about 150 characters.

Questions and answers

Is sitelens free?

Yes. Both the online version and the terminal tool are free, and the code is open source under the MIT license.

Do I need an API key?

No. Under heavy traffic the online version may ask for your own free Google PageSpeed Insights key. AI features are optional and only run on your own Anthropic key, which stays in your browser.

Is my website data sent anywhere?

The terminal tool runs entirely on your computer. In the online version the address goes to Google PageSpeed Insights, and the public page content passes through our server only for the audit and is not stored. Results and the report are created in your browser. Details are in the privacy policy.

Does the audit change anything on my website?

No. sitelens only fetches public pages, like any visitor. It does not submit forms and does not store anything on the server.

How is it different from Lighthouse alone?

Lighthouse measures one page and describes the results in developer language. sitelens uses Lighthouse and axe-core, adds its own checks (such as security headers, the sitemap and redirects), checks several pages at once and turns every problem into concrete steps in a PDF report.

Which systems does the terminal tool run on?

macOS, Windows and Linux. One command installs everything sitelens needs, and with Node.js 22.19 or newer npx sitelens is enough. See the step-by-step guide.