Today we talk about the principles of usability in an APP and what we should pay attention to in the design.


We understand usability by how easily it facilitates the user to reach their goals while interacting with it.

The term usability is commonly associated with the usability of websites or software, but the usability of mobile applications is also a very important factor.

Many books have been written on web usability, on the principles of web usability, on tricks and tips etc., and although the world of mobile devices and apps is booming and gaining a lot of ground, there are few references about Usability in this sector.

Given the importance of having good usability in our mobile applications, Checkealos wrote today, among others, about what are the principles of usability in an APP, and how they are determined and what we should pay attention to the usability in designing these.










The structure of the app and the distribution of the elements must be carefully studied since you have to take into account the gestures of the users, the size of the screen, if the user uses one or two hands, if the app will be presented in Vertical, horizontal or both positions, etc …

In a mobile device (Tablet or Smartphone) the user has certain limitations and difficulties to press certain parts of the screen due to the use of the fingers in a reduced area. For this reason there are certain areas of the screen where the situation of buttons and interactive elements are easier to access the user than others, depending on whether the app is presented vertically or horizontally



If the app is used vertically and with only one hand, you must take into account the length of the fingers and how far they can reach comfortably.

If it is used vertically and with two hands, it is necessary to take into account the way in which the device will be held with the other hand and to prevent that the hand that holds the device obstructs the pulsation of links or the reading.

On the other hand, if the app is used horizontally and the device is held with both hands, it is necessary to take into account the length of the user’s fingers that will hardly touch comfortably links or buttons that are on the top from the screen.




The user of the mobile applications is more interested in the content than in the interface, in the graphic design etc.

Due to various circumstances like time, screen size, … the user of apps wants to focus on the content, to be shown quickly, directly and clearly.

Interface, design and other factors are important, but content is what really interests the user.

In this sense, the images are of great value to the user and the text should be clear, concise and direct.

Although the information offered in a mobile version is smaller than in the web version, it should be more direct and relevant and should never give the impression that the web version is more complete than the mobile version




The size of texts, buttons and images in applications is smaller than in a web because of the limitations of sizes and resolutions of the screens of mobile devices so that all elements must be scalable so that the user Can read them, consult them and press them more easily and avoid mistakes.




An APP must be fully optimised for use on mobile devices, if possible for all types of devices and for all types of operating systems and platforms.

That is, if we design an app we must take into account the limitations of screen sizes, resolutions; We can not design an app so that when used in a horizontal position, its width is not completely displayed and horizontal scrolling is necessary. To avoid this type of usability errors it is advisable to use adaptive or responsive designs.

Or if a platform or operating system does not support flash animations, we can not offer an app that contains animations in this format.



When designing an App and offering a good usability we must pay attention to a number of factors such as:

  • What is the purpose of the app ?: The distribution, options and number of elements will depend on the type of App and its purpose.
  • Who will use it ?: The App will be designed based on the profile of users who will use it.
  • Where is it going to be used and how ?: It is necessary to take into account in which type of device we want to offer mainly the application (although we optimise it for all type of devices) and how we predict that it will be used (Horizontal or vertical)
  • What needs does the user have ?: Depending on the profile of our end users, the App will have to cover a series of needs or others, with some options and functions or others.
  • What do we want to offer? What do we expect?: What we want to offer through our App, what we expect the user to do or get will be of special relevance when designing our App.




Here are some tips that help an App to offer optimal usability:

The App always in the same window:On certain mobile devices, switching windows is complicated and can cause confusion, so the app and its screens are convenient to always be displayed in the same window.

Offer access to web version: Not all users who access a mobile version or an app are comfortable with them so it is recommended to provide access to the web version

Reduced forms: Writing on smartphones and tablets is often not easy or fast so, the forms should be as short as possible, ask only the strictly necessary data

Button size: The buttons and links in the app must be large enough to make your pressing comfortable and avoid pressing unwanted buttons

Search Tips: Since typing on mobile devices is sometimes not comfortable, displaying suggestions as they are filled in fields is always grateful to users

Filter System: Filters make browsing and searching apps faster and more convenient

Protagonism of the main action: The main action must take center stage in the screen of the app and not be lost between functions, options, ads, etc

Direct access to information: Accessing information in an app has to be easy, fast, and convenient. It is not convenient that the user has to make too many clicks or surf in excess to reach the information he wants

Contrast: Display on mobile devices is usually not overly comfortable so the app should offer a high contrast between text, buttons and background

Handling with a single finger: To provide good usability, the user should be able to use the app with a single finger

Avoid excess elements: A clean and clear interface, where clearly highlight the information and links makes its use more comfortable

Send and share options: Offer the ability to send an app link and share on social networks

Short menus: Menus with too many options are not comfortable on mobile devices

Aligned buttons and links: The horizontal or vertical alignment facilitates its identification and its pulsatio

The important thing above: The most important information as well as the most important options and functions will be located at the top of the screen

Few categories and subcategories: Grouping elements and information into a few categories and subcategories is more convenient and effective for the user than offering a wide range of options

Do not exceed 70 characters per line: Including lines longer than 70 characters may make it difficult to read on mobile devices.

Standard icons: It is advisable to use standard or easily recognizable icons.

Intuitive App: Navigating on a device is not always comfortable so, the app must be intuitive, the user has to be able to scroll through the different screens and options without thinking.

Key highlights and quick access sections: The main sections and functions have to be clearly highlighted and have to be easy and quick access for the user.

Minimise the scripts executed by the client: Mobile devices have hardware limitations so running a large number of scripts on the device can slow and even block the App.

Avoid downloads: Mobile devices suffer incompatibilities with various types of files and downloading files can overwhelm the device capacity.

Logo link: In an app it is very convenient for the user that the logo is a link to the main page.

Do not limit functions: It is not convenient to include functions that can only be performed in a way such as talking, moving the device, … alternative methods should be offered as buttons.


Take action with Checkealos:

  • Blocked in the design of your app? Find out how our usability and user experience specialists can help you.
    Expert Review.
  • Know the needs of users of application or game from its beta phase and improves its usability before launching it to the market. Usability testing
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User Experience SL 2018