What we check

AI readability

AI assistants can read the website and match it with the right organisation.

• Structured company data

  Does the home page state the name, address and industry of the company or organisation in a machine-readable form (Schema.org)?

• Company details in Schema.org

  How complete is the structured company data, with logo, address, opening hours, service area and services?

• Marked-up content

  Are questions, services, articles or testimonials on the home page marked up in a machine-readable way?

• Linked profiles

  Does the website link its social media profiles to the company or organisation in a machine-readable way?

• Valid structured data

  Is the structured data of the home page free of errors, so that Google and AI assistants can use it?

• Access for AI services

  May AI assistants such as ChatGPT, Claude and Perplexity read the website, and does the firewall let them through?

• Preparation for AI assistants

  Does the website offer a summary for AI assistants (llms.txt) or a Markdown version of the home page?

• Content pages

  Does the home page link to pages that introduce the company, describe services and show references?

• Semantic HTML structure

  Does the home page mark up the header, navigation, main content and footer with the appropriate HTML elements?

• Text share

  Does the home page contain enough readable text that Google and AI assistants can reproduce?

• Content readable without JavaScript

  Is the text of the home page directly in the HTML, or does it only arise through JavaScript in the browser?

Search engine friendliness

Be found when someone searches on Google.

• Page title

  Does the home page have a meaningful title that names its topic?

• Description for Google

  Does the home page have a description for the search result, and is its length right?

• Main heading

  Does the home page have exactly one main heading (H1)?

• Structure of headings

  Do the headings of the home page form a gapless structure, and do they introduce real sections?

• Main heading fits the content

  Do the terms of the main heading also appear in the text of the home page?

• Readable and findable by Google

  Do "noindex", the robots.txt or a wrong canonical tag exclude the home page from Google search, and may Google quote it?

• Canonical tag

  Does the home page tell Google its own valid address?

• Redirect with and without www

  Does the website redirect cleanly to the main address in the other spelling, with or without www?

• Language details

  Does the HTML of the home page state the language of the content?

• Language versions (hreflang)

  Are the language versions of a multilingual website linked to each other correctly?

• Sitemap

  Does a valid sitemap show Google all pages of the website, without broken addresses and redirects?

• Broken links

  Do the links on the home page lead to working pages?

• Readable addresses (URLs)

  Are the addresses of the subpages short, speaking and permanent, or do they consist of numbers, parameters and file extensions?

• Breadcrumb navigation

  Do the subpages show a trail such as "Home › Services › Heating", visibly and as structured data for Google?

• Error page (404)

  Does the server correctly answer addresses that do not exist with "404 Not Found"?

• Preview on social media

  Does the home page show an attractive preview when shared on LinkedIn, Facebook, WhatsApp or X?

Security

Protection against attacks and forged emails in the company's name.

• Encrypted connection (HTTPS)

  Is the website delivered encrypted, and does the unencrypted address redirect to HTTPS?

• Security certificate

  Is the certificate of the website valid, does it not expire soon, and does it use current encryption?

• Unencrypted content on HTTPS pages

  Does the encrypted page load scripts, images or forms over unencrypted HTTP?

• Protective settings of the server

  Does the web server send the most important security headers, and are they set effectively?

• Protection of cookies

  Does the server set cookies with the Secure, HttpOnly and SameSite attributes?

• Outdated software

  Does the website run software that no longer receives security updates?

• JavaScript libraries with known vulnerabilities

  Does the website load JavaScript libraries such as jQuery in versions with known security vulnerabilities?

• WordPress plugins with known vulnerabilities

  Does the WordPress website use plugins in versions with publicly known security vulnerabilities?

• Protection against email fraud

  Do SPF, DKIM and DMARC prevent fraudsters from sending emails with the domain's sender address?

• Permitted certificate authorities (CAA)

  Does the domain define which authorities may issue security certificates for it?

• Contact for security issues (security.txt)

  Do security researchers find an address on the website where they can report a vulnerability they discovered?

• Signed DNS records (DNSSEC)

  Are the DNS records of the domain digitally signed, so that nobody can redirect visitors to a foreign server?

Performance

Fast pages lose fewer visitors before they get in touch.

• TTFB (Time to First Byte)

  How long does the server take until the first byte of the response to a page request?

• Loading time and Core Web Vitals

  How fast does the home page load on a smartphone, does it jump while loading, and how quickly does it respond to clicks?

• Images

  Are the images on the home page loaded in modern formats, a suitable size and with lazy loading?

• Data volume of the home page

  How much data and how many requests does the home page load on the first visit on a smartphone, and what does that mean for loading time and CO₂?

• HTML document

  How fast does the HTML of the home page load, redirects included, and how large is it?

• Text compression

  Does the server transfer the page compressed so that it arrives faster?

• Transfer protocol

  Does the server deliver the page over modern HTTP/2 or HTTP/3?

• Blocking files

  How many stylesheets and scripts hold up the page build before visitors see anything?

• Browser cache

  Does the server allow the browser to cache images, stylesheets and scripts?

Mobile

Most visitors come from a smartphone.

• Viewport and zoom

  Does the page tell the smartphone how wide it should be displayed, and may visitors zoom in?

• Appearance on a smartphone

  Does the home page work on a smartphone without sideways scrolling, with readable text and buttons that are easy to hit?

• Images in a suitable size

  Are large images offered in several sizes so that smartphones do not load desktop images?

• Table layout

  Does the home page use tables as a frame for the page layout instead of only for data?

• Tappable phone number

  Can visitors place a call from the home page with one tap on a smartphone?

Privacy

Less risk of privacy complaints.

• Privacy policy and imprint

  Does the home page link to a privacy policy and an imprint, and do these pages have content?

• Date of the privacy policy

  Is the privacy policy dated and revised in line with the revised Data Protection Act of September 2023?

• Third parties before consent

  Does the home page transmit data to tracking services and other third parties on the very first visit?

• Cookie notice

  Does a cookie notice appear on the first visit if the page sets analytics or advertising cookies?

• Effect of the cookie choice

  Does the cookie notice offer rejecting on the first layer, and does the page stick to it?

• Server location

  In which country is the server of the website located, or is it delivered via a CDN?

Accessibility

More reach, including among older people.

• Accessibility (automatic preliminary check)

  Which barriers does an automatic test find on the home page, such as missing image descriptions or too little contrast?

• Operation with the keyboard

  Can the home page be operated with the Tab key, and can you see where you are while doing so?

• Media that starts by itself

  Do videos or sounds on the home page start by themselves, and can they be stopped?

• Accessible PDF documents

  Can blind and visually impaired people read the PDFs the home page links to, or are they images without text and structure?

• Accessibility statement

  Does the website say how accessible it is, where it still falls short and whom people with disabilities can contact?

Markup

Error-free HTML is read reliably by browsers, Google and AI.

• HTML5 doctype

  Does the home page begin with the modern declaration "<!DOCTYPE html>"?

• W3C validation

  How many errors does the official W3C validator find in the HTML of the home page?

• Outdated HTML elements

  Does the home page use HTML elements that were removed from the standard, such as font, center or marquee?

• Duplicate IDs

  Is the same ID assigned several times on the home page, which disturbs forms, jump links and screen readers?

• JavaScript errors

  Do scripts stop with errors while the home page loads?

• Missing files

  Does the home page request scripts, stylesheets, fonts or images that the server does not deliver?

• Inline styles

  How many elements of the home page carry their styling directly in the HTML instead of in a CSS file?

• Size of the HTML

  How many HTML elements does the home page consist of, and does this slow down the page build?

• Character encoding

  Do server and HTML agree on UTF-8 so that umlauts appear correctly?

• Technology in use

  Which technology does the website use, from the CMS and hosting to analytics tools, and are parts of it old?