Lessons

Introduction
• SEO
  • Snippet's clickability in search engines
    Description Meta Tag Title tag Spelling errors in the title or meta tags Content of the Title Title Brand name in the Title header
  • Indexing
    Headings H1-H6 Images have the "alt" attribute. The Title attribute of links Content robots.txt Duplicate "title" Duplicate "description" Human-understandable name of the picture Rules for formatting text on a page Micro-markup format requirements and recommendations Validation microdata Google Human-friendly link format Errors in Robots.txt The content of the site map The site map file Link formatting requirements Hreflang tag "canonical" tag Spelling of interactive interface elements
• Speed
  • Number of network requests
    An overabundance of small pictures Grouping CSS files Grouping JavaScript files An overabundance of font files Redirects when uploading files Availability of end-to-end CSS, JS files Uploading duplicate files Using JavaScript facades Redirecting JavaScript code Redirect from/to www version Using sprite technology The video player is connected correctly
  • General assessment
    Page load time Display time of the first graphic
  • Server Settings
    304 response code when checking the operation of caching ETag header for caching operation The "Expires" header for caching to work Server GZip compression function Title "Keep alive" Using the modern HTTP2 protocol to speed up the site
  • Showing the first content
    Specifying default fonts Font display mode Setting up a pre-connection Deleting a delayed download File upload delayed or on demand
  • Size of graphic files
    Minification of the embedded JavaScript code of the page Minification of the embedded CSS code of the page Minification of images without loss of quality The total size of all images on the page Font Optimization An overabundance of monochrome icons The presence of a monochrome font Data optimization:Image URLs Animated image format MP4, WEBM, SVG instead of GIF and WEBP Cropping monophonic fields in images Using the WebP format in images Too high-quality images without using compression Suitable video bitrate Excessively large images
  • Server performance
    HTML code generation time Optimal time to download files from the server Time to download files from the server under load
  • Blockages
    The sequence of connecting JavaScript files Adding lazy loading Long JavaScript code execution time The server is located in the same country where the users of the site live No requests to another country that cause page loading to be blocked Blocking files
  • The amount of code
    Minification of CSS to reduce its volume Acceptable size of the HTML code of the page Minification of JavaScript files to reduce its volume Unused CSS code Unused JavaScript code
• Mobile adaptation
  • Broken layout
    Horizontal scrolling of the screen Major headlines The block goes off the screen
  • Convenience
    Finger friendly Blurry images
• Software errors
  • Code
    JavaScript files are not available for download Broken links JavaScript error messages in the browser console HTML Validation Validation of CSS code
  • Mail operation
    SPF DNS server record DMARK DNS server record MX record of the DNS server Reverse DNS record
  • Availability
    AAAA DNS server record IPv6 connection
  • Server Settings
    Configuring HTTP Headers Erroneous extension of images Corrupted files Matching the Mime Type to the file
• Convenience
  • Text readability
    Sufficient text contrast Readable text size Line spacing of the text The size of the text in the pictures
  • Interface
    The page links to itself. Cyclic references. Link to the main page of the site Interface responsiveness
  • Visual defects
    CSS files are not available for download Images are not available for download Beautiful page 404 Background image flickering on hover Images when loading cause a sharp change in the structure of the page Recompressed images with artifacts Deformed images
  • Interaction with other programs
    Splitting the page into HTML5 sections Phones without a clickable link to start a call quickly Links for Email addresses Snippets of the site when sending links in social networks and instant messengers Annoying pop-up messages without the user's knowledge
  • Image Favicon
    Manifest validation.json with a list of favicons Tag for specifying a large favicon The BrowserConfig file Apple touch bar icon for Mackbook pro Favicon.ico file
• Vulnerabilities
  • Code
    CSFR protection of HTML forms Vulnerable JavaScript code Vulnerable JavaScript libraries
  • Server Settings
    Uploading all page files via HTTPS Strict-https header for increased security Private access to service files Encrypted IPv6 connection Enabled error display in the north SSL certificate validity HTTPS Availability Redirects to protected Vulnerabilities of a secure SSL connection HTTP headers for increased security
  • Third-party services
    Using Java applets Antiviruses