Help and documentation

Complete explanation of all recommendations — what it is, why it matters and how to do it.

SecurityCritical impact

HTTPS / secure connection

The site must run on HTTPS with a valid certificate.

SecurityCritical impact

HTTP status code and availability

The page must return a 200 code and be reliably available.

SEOCritical impact

Title tag (page title)

Every page needs a unique, descriptive title of 50–60 characters.

SEOHigh impact

Meta description

A short page description (120–158 characters) shown under the title in results.

SEOLow impact

Meta keywords (Seznam.cz)

Keywords in <meta name="keywords">. Google ignores them, Seznam.cz may consider them.

SEOHigh impact

Headings H1–H6 (structure)

Exactly one H1 and a logical hierarchy of subheadings.

SEOMedium impact

Images and alt texts

Images need an alt description, a modern format, and compression.

UX / UICritical impact

Viewport / mobile display

The meta viewport ensures correct display on mobile.

SEOMedium impact

Language declaration (lang)

The lang attribute on <html> specifies the page language.

SEOHigh impact

Canonical URL (canonical)

Tells search engines which version of a URL is the main one.

SEOCritical impact

Robots (indexing and robots.txt)

Controls what search engines may crawl and index.

SEOMedium impact

Open Graph (social media previews)

Controls how a link looks when shared on Facebook, LinkedIn, etc.

SEOLow impact

Twitter Cards

Link preview on the X (Twitter) platform.

GEO / AIHigh impact

Structured data (Schema.org)

Machine-readable markup that unlocks rich results.

SpeedHigh impact

Loading speed

Speed is both a ranking factor and a key UX element.

SEOMedium impact

Links (internal and external)

Working links and meaningful internal linking.

SEOLow impact

Favicon

The site's icon in the tab and in mobile results.

SEOMedium impact

URL structure

Short, readable, and logical addresses with keywords.

SEOHigh impact

Content quality and length

Sufficiently comprehensive, readable, and unique content.

SpeedHigh impact

Defer / async on scripts

A synchronous <script> blocks rendering — defer it.

SpeedHigh impact

Render-blocking resources

CSS and JS in the head that delay the first render.

SpeedHigh impact

Reducing blocking CSS

Large CSS in the head delays rendering.

SpeedHigh impact

Response compression (Gzip/Brotli)

Without compression, an unnecessarily large amount of data is transferred.

SpeedHigh impact

Enabling compression

Compression is not active — enable Gzip/Brotli.

SpeedMedium impact

Browser caching

Static files should be stored at the visitor's end.

SpeedMedium impact

Lazy loading images

Load off-screen images only when scrolling.

SpeedMedium impact

Modern image formats (WebP/AVIF)

WebP and AVIF are 25–50% smaller than JPEG/PNG.

SpeedHigh impact

TTFB — server response

The time before the server sends the first byte of the response.

SpeedHigh impact

Total page weight

A page that's too large loads slowly.

SpeedHigh impact

Reducing page weight

The page is large — lighten it.

SpeedMedium impact

Number of HTTP requests

Many files = many requests = a slower start.

SpeedLow impact

Fewer CSS files

Combine and minify styles.

SpeedMedium impact

Less and smaller JavaScript

Large JS delays and burdens the device's CPU.

SpeedMedium impact

DOM size

Too many HTML elements slow down rendering.

SpeedMedium impact

Excessive DOM

The element count exceeds a reasonable limit.

SpeedLow impact

Inline styles

Lots of style="..." worsens caching and maintainability.

SpeedLow impact

Inline scripts

Many <script>s directly in the HTML block and can't be cached.

SpeedMedium impact

Image dimensions (width/height)

Without image dimensions, the layout jumps (CLS).

SpeedLow impact

Preloading key resources (preload)

Important resources can be loaded earlier via rel="preload".

SpeedMedium impact

HTTP protocol version

HTTP/2 and HTTP/3 are faster than the old HTTP/1.1.

UX / UIHigh impact

Blocked page zoom

Never prevent the user from zooming the page.

UX / UIHigh impact

Font too small

Body text at least 16px, fine print at least 12px.

UX / UIMedium impact

Readability and size of links/buttons

Clickable elements must be readable and easy to hit.

UX / UILow impact

Relative font units (rem/em vs px)

Prefer rem/em over fixed px for font sizes.

UX / UIHigh impact

Text contrast against the background

Text must have sufficient contrast (WCAG AA 4.5:1).

UX / UIMedium impact

Responsive images

Images must fit on mobile without horizontal scrolling.

SEOMedium impact

XML Sitemap

A list of URLs for search engines — helps faster indexing.

SEOMedium impact

Search result preview (SERP snippet)

How the page looks in Google's results.

SEOMedium impact

Hreflang (multilingual sites)

Tells Google which language version belongs to which audience.

UX / UICritical impact

Mobile friendliness

Google primarily evaluates the mobile version (mobile-first).

SecurityHigh impact

Site security

HTTPS, security headers, and protecting visitors.

SEOMedium impact

Redirects

Short 301 chains, no loops.

SEOLow impact

Technologies in use

An overview of the site's CMS, frameworks, and libraries.

UX / UIHigh impact

Accessibility (WCAG)

A site usable even by people with disabilities.

SecurityMedium impact

Cookies & GDPR

Cookie consent and personal data protection.

SecurityMedium impact

DNS & SSL certificate

Correct DNS records and a valid SSL certificate.

SEOMedium impact

Broken links

Links leading to a 404 spoil both UX and the crawl.

GEO / AIHigh impact

GEO — optimization for AI search engines

So that ChatGPT, Gemini, Perplexity, and others cite you.