Main assumptions of WCAG 2.1


All public entities' websites and mobile applications must be accessible digitally. This results directly from the Act of April 4, 2019. on digital accessibility of websites and mobile applications of public entities.

WCAG is an abbreviation of Web Content Accessibility Guidelines, i.e. guidelines for the availability of web content. Version 2.1 of these guidelines is currently in force.

They describe how to create a website or a mobile application so that they can be picked up by people with disabilities, e.g. eyesight, hearing, movement, but also for people with intellectual disabilities and cognitive difficulties.

WCAG 2.1 is based on 4 main principles:

  • perceptibility
  • functionality
  • intelligibility
  • solidity

The above rules are not a set of strictly technical comments, but rather force you to think about different website users. Therefore, the creator of the website should consider, for example, how will he adjust the photos on the website for people who cannot see them? How will I schedule site navigation for non-mouse users? How will it ensure accessibility for people who need to enlarge the page size or change its colors? These are just some of the many issues that we must remember when creating an accessible website. Importantly - the principles of digital accessibility apply to both the website code, its content and the way it works. Therefore, creating a website requires the cooperation of the entire team responsible for individual elements.

Let's try to disassemble each of the four key principles of digital accessibility into factors. They are broken down into 13 guidelines, each with specific requirements (known as "success criteria").

1. Perceptibility

Provide the ability to use the website or mobile application with the senses available to users. You can get it thanks to:

  • alternative texts for non-text content (e.g. description of photos and graphics will be helpful for the blind)
  • subtitles for audio and video materials (it will be invaluable support for deaf people)
  • the logical structure of the page content (headers, lists, etc. will be helpful for people using screen readers)
  • appropriate markings of each function (e.g. form), so that the relationship between the content is correctly defined
  • honors based solely on color
  • appropriate contrast on the page and the possibility of its individual adjustment
  • readability of the page when it is increased by 200%
  • not publishing texts in the form of images (e.g. scans of documents as unreadable PDF files will be impossible to read by people using screen readers)
  • ensuring responsiveness - adapting the website view to the screen size of the device (so the website should be readable not only on computer monitors, but also on tablets and smartphones)

2. Functionality

Create the ability to find and use content regardless of how the user navigates the page (e.g. uses only the keyboard or the mouse). The following will be helpful in this:

  • the ability to handle everything with just the keyboard
  • allowing you to play, pause or stop moving items
  • not placing flashing content on the website (it will be bothersome e.g. for people with photosensitive epilepsy or with sensitive eyesight)
  • placing a link that allows you to quickly jump to specific content
  • Providing clear and relevant page titles and link descriptions that tell you where they lead
  • in the case of forms, provide labels and descriptions explaining what to enter in a specific field
  • clear visibility of the item currently selected with the keyboard
  • simple gestures on touch screens
  • possibility to modify keyboard shortcuts

3. Understandability

Make the content and operation of the website understandable to users. You can achieve it thanks to:

  • simple language (avoid official and highly specialized language)
  • present content briefly and concisely, eliminate unnecessary words
  • explain the abbreviations and acronyms used
  • put information about the language of the page content in the page code
  • ensure a consistent appearance of individual subpages
  • put understandable labels in the form fields as well as clear form error messages and instructions on how to correct them

4. Reliability

This principle is called "compatibility". Provide the ability to use the website or mobile application in multiple user programs (e.g. web browsers and screen readers for the blind). You will get it thanks to:

  • using the correct code compliant with the HTML web standard
  • available to users using status information assist technologies
  • reporting by assistive technologies of appearing messages or modal windows