Mobile application interface

The interface of a mobile application is the face of your product, which directly affects market success. According to Forrester Research, every dollar invested in improving UX brings $100 in profit - an ROI of 9900%. At the same time, 70% of online businesses fail due to poor usability.

In 2024, when more than 70% of Internet traffic and 50% of online sales are made on smartphones, a high-quality mobile interface is becoming a prerequisite for survival. It is not enough to simply transfer the functionality of the web version to the phone screen - you need to adapt everything to the scenarios of a mobile user.

In this guide, we will analyze it:

• What is a mobile app interface and what tasks it solves
• How the interface is designed at different stages of application development
• What UI/UX design principles are relevant for 2024
• How to optimize the interface taking into account user psychology
• What mistakes are most often made when creating interfaces
• What tools are available for prototyping and testing

Let's go!

What is a mobile app UI?

The mobile app UI is a set of visual and interactive elements that help users interact with the application and receive feedback from it.

The main task of the UI is to make this interaction as simple, clear, and enjoyable as possible so that the user can easily achieve their goals: find information, make a purchase, chat with friends, play, etc.

At the same time, the interface should also solve business problems: attract and retain customers, increase conversion and profit, and strengthen the brand image. Therefore, a UI/UX designer always balances the user's needs and business goals when creating an interface.

A high-quality mobile interface should be:

1. Simple and intuitive. At a glance, the user should understand how to navigate between screens and where to look for the necessary functions. Ideally, it should take no more than 15-20 seconds to master the interface.
2. Adapted for small screens and touch controls. The average diagonal size of a smartphone in 2024 is 6.7 inches. Therefore, buttons and other elements should be large enough, contrasting enough, and located within reach of fingers.
3. Consistent and predictable. Interface elements should behave in the same way on all screens. Users should know exactly what will happen when they click.
4. Aesthetic and consistent with the corporate identity. The interface should be visually appealing, modern, and reflect the character of the brand through colors, fonts, icons, animations, and other UI elements.
5. Fast and responsive. According to Google research, 53% of users leave a website if it takes longer than 3 seconds to load. This fully applies to applications - no one will wait.
6. Accessible to all users, including people with visual, hearing, and motor impairments. This means that you need to provide sufficient sizes of clickable zones, support for gestures, interface voice, and video subtitles.

The interface is the first thing a user notices when they download an app. You have only 8 seconds to make a good impression. If the interface is complicated, ugly, or slow, the app will be deleted immediately, and you won't get a second chance.

So don't skimp on UI design - it's an investment that will pay off many times over through user loyalty and conversion. As Steve Jobs said: "Design is not how a product looks. Design is how it works." And in the case of mobile apps, it works primarily for business results.

Stages of mobile app interface development

UI development is a complex process that begins long before the first mockups are drawn and continues after the app is released. It includes the following stages:

1. Researching the target audience and competitors. Before designing an interface, you need to clearly define who you're making it for. Create detailed portraits of potential users: their demographics, goals, pains, and scenarios for using the app. Study the top competitors in your niche: their strengths and weaknesses, interface features.
2. Building an information architecture (IA). At this stage, the logical structure of the application is designed: how the content will be organized, what screens it will be distributed on, and how users will move between them. The main task is to make information search and navigation as simple as possible. The result of this stage is a sitemap or user-flow diagram.
3. Creation of wireframes. A wireframe is a low-detailed black-and-white layout of an interface that defines the structure and location of the main elements on each screen. It allows you to focus on usability and architecture without being distracted by graphics. First, sketches are drawn on paper, then they are detailed in special software such as Balsamiq, Moqups, Figma.
4. Development of visual design (UI). At this stage, wireframes are filled with graphic elements: colors, icons, illustrations, and photos. The designer creates several visual style concepts and, after approving the best one, works on all screens in detail. For this purpose, graphic editors such as Photoshop, Sketch, Figma, and Adobe XD are used. It is important to immediately adapt the design to different screen sizes (responsive design).
5. Interactive prototyping. To test not only the appearance but also the logic of the interface, static mockups are combined into a clickable prototype. It simulates the operation of the application: it allows you to click on buttons, navigate between screens, and interact with elements. To create prototypes, we use Invision, Marvel, Principle, ProtoPie, as well as the built-in capabilities of Figma and Adobe XD.
6. Usability testing and feedback collection. The interactive prototype is shown to potential users and how they handle it. Problems and issues that arise are recorded, and the time to complete key scenarios is measured. The collected feedback is used to improve the interface. Testing is done cyclically at different stages of product readiness. Tools: UsabilityHub, CrazyEgg, HotJar, Google Analytics.

The work on the interface does not end after the release. Analytics of application usage and feedback from real users become the main source of ideas for its improvement. Large product companies conduct A/B tests and interface redesigns every 6-12 months. High-quality UI is always a work in progress.

Key principles of mobile UI design in 2024

To create an interface that will be one step ahead of competitors and trends, it's not enough to just follow a checklist of best practices. You need to understand the fundamental principles of UI/UX design and be able to apply them to new challenges. Here are the main ones for 2024:

1. User-first approach. The most important principle is that the interface should be developed not for the sake of a pretty picture, but to solve specific user tasks. That's why researching the target audience and building user scenarios is the first and most important stage of work. The best interfaces are so intuitive that the user feels as if they were made personally for him or her. To achieve this, designers use personalization: they adjust content and UI elements to the preferences and behavior of a particular person.
2. Simplicity and minimalism. In the pursuit of beauty and functionality, it is easy to overload the interface. But the more elements on the screen, the harder it is for the user to concentrate on the main thing. Therefore, modern interfaces tend to be simple and minimalistic. Everything superfluous is removed, only the most important remains. User paths are simplified: everything that can be done in 1 click does not have to be done in 2. This is done by prioritizing content, progressive disclosure of functionality, and adaptive interfaces.
3. Focus on the thumb. Phones grow in size, but the anatomy of the human hand remains unchanged. The comfort zone of the right thumb is the center of the lower half of the screen. This is where the most important navigation and action elements should be located. And the things you need to reach for should be at the top or at the edges. In addition, you need to make buttons and links large enough (at least 7-9 mm) and indent between them (>2 mm).
4. Smart animation and micro-interactions. Animations not only liven up the interface, but also perform important functions: they draw attention to the desired objects, explain what will happen when you click, indicate the completion of an action, and so on. Micro-animations when hovering, clicking, scrolling, and loading give the user a sense of feedback and control. But animations should not be intrusive and slow down the interface. In 2024, the trend will be smooth and realistic animations based on the physical properties of objects.
5. Unlimited and immersive design. To expand the screen area, designers are increasingly using bezel-less displays and thin bezels. Therefore, borderless UI is in fashion, where the content seems to go beyond the screen. Also, immersive elements are used to deepen the user's immersion in the interface: 3D, parallax effects, translucent layers, gradients, and fluid shapes.
6. Voice control and chatbots. Voice assistants and chatbots have become a common interface in smartphones. According to Juniper Research, the number of voice assistants will grow to 8.4 billion by 2024. At the same time, 90% of interactions with brands will be automated through chatbots. Therefore, a modern mobile interface should be ready to accept voice commands and give voice feedback, understand natural language and support dialogues.
7. Augmented reality (AR). The impetus for the mass adoption of AR was the launch of ARKit by Apple and ARCore by Google. Today, AR is used not only in games but also in shopping, education, tourism, and interior design. Using a smartphone camera, AR overlays digital content and interactive elements on real objects. For example, it allows you to try on virtual clothes, arrange furniture in a room, and see interesting places around you. In 2024, the AR interface will become a mandatory feature of many applications.

The main challenge for a designer is not to blindly pursue fashion, but to choose the principles and approaches that will solve the problems of specific users and businesses. Early feedback and regular testing of hypotheses on users will help to identify them.

Visual interface design trends in 2024

The visual design of a mobile application is the first thing a user pays attention to. And if earlier skeuomorphism and flat design were in trend, now neomorphism and 3D elements are at the peak of popularity.

Neomorphism combines the features of skeuomorphism and flat design. It uses minimalistic objects, but with realistic shadows and lighting effects that create a sense of volume. In contrast to the strict geometry of the flat, neomorphic buttons have smooth asymmetrical edges. The background is often made in pastel colors.

Three-dimensional graphics and animation have become popular not only in games but also in regular applications. 3D icons, illustrations, and screen transitions liven up the interface and draw attention to details. Translucent layers and realistic shadows are used to add depth. However, it is important not to overload the interface so as not to reduce performance.

Another trend is saturated colors and gradients. In 2024, bright, contrasting combinations that create a mood and set the app apart from competitors will be in fashion. Gradients have become smoother and more natural. They are often used to create the effect of lighting or shading. But you need to keep an eye on contrast and readability.

Many designers use simple geometric shapes (circles, squares, triangles) as a basis for creating more complex shapes and patterns. They can form an abstract composition or be folded into recognizable icons. Overlapping shapes and "torn" asymmetrical edges are popular.

In the pursuit of uniqueness, brands are increasingly using custom graphics:

1. Custom abstract illustrations
2. Stylized 3D characters
3. Animated elements

They not only decorate the interface, but also direct the user's attention and convey the character of the brand. It is important that the graphics are related to the content and functions of the app.

Typography plays a huge role in usability and visual style. In 2024, the trend will be:

• Big, bold headlines that draw the eye
• Sufficiently contrasting and legible body text
• Branded fonts and combinations of different fonts
• Experiments with 3D text, gradients, and shadows

But it's not enough to just throw in some trendy elements - visual design should work in conjunction with UX and content. You need to find your own corporate identity that suits your audience and business objectives.

Optimizing the interface for human behavior

No matter how good the design is, if it is inconvenient to use, the application will fail. Therefore, it is important to take into account the psychology and physiology of users when designing.

Smartphone users have already formed strong habits - scrolling through content from top to bottom, clicking on the navigation at the bottom of the screen, looking for a menu in the corner. If your interface works differently, it will cause irritation. It's important to follow platform guidelines and use standard templates, and explain new gestures with tips.

75% of people operate a smartphone with one hand, with their thumb. That's why the most important interface elements should be at the bottom of the screen, and the secondary elements should be at the top. Buttons should be large enough (at least 9 mm) to be easy to reach.

The human brain likes order. Therefore, related functions should be grouped visually (using frames, colors) and placed side by side. This will simplify navigation and reduce the burden on the user.

The golden rule of UX is that the fewer actions required to achieve a goal, the better. Each extra click increases the likelihood that a person will abandon the task. The interface should lead to the shortest path:

1. Put key buttons on the main screens
2. Break large forms into steps
3. Remove all unnecessary things

Finally, the key factor is speed. The average user expects a 2-second download, otherwise 30% leave immediately. Therefore, you need to optimize:

• Loading time (due to compression, caching, etc.)
• Speed of response to actions (animations no longer than 0.1 seconds)

The best way to check the usability of an interface is to test it on real people. Imagine that your relatives who are not tech-savvy will use the app. If they feel comfortable, you've done everything right.

Features of interfaces for different types of applications

Although the general principles of UI design are universal, each application niche has its own specifics that are important to consider. Let's analyze a few examples.

E-commerce interface (marketplaces, stores):

• Focus on product catalogs, cards, shopping cart
• Easy navigation by categories and filters
• Large photos, the ability to zoom in, see details
• Reviews, ratings, recommendations of similar products
• Several payment and delivery methods to choose from
• Order status, parcel tracking, chats with the seller

An example of a good eCommerce interface is the Rozetka app. It has a clear category structure, smart search, detailed descriptions and live photos of products, convenient comparison, several payment and delivery options. Everything is subordinated to the main goal - to quickly and easily find and order the right product.

Interface to social networks and messengers:

• An endless feed with a variety of content
• Stories, clips, polls to increase engagement
• Private messages and group chats
• Notifications about new events, reactions
• User profiles with their content and connections
• Opportunities to create your own content (photos, videos, posts)

TikTok is an example of a new generation social media interface. A fascinating feed of short videos adapted to the user's preferences. The ability to easily create, edit, and promote your own videos. An effective system of engagement through challenges, duets, and reactions. Minimal distractions - focus on video.

Interface of educational applications:

• Structuring the material by courses, lessons, topics
• Video lectures, presentations, interactive tasks
• Communication with teachers and classmates through chats, forums
• System of grades, tests, progress tracking
• Reminders about classes and deadlines
• Gamification for motivation (points, badges, ratings)

A good example of a learning platform interface is Coursera. There is a clear division into courses and modules, video lectures with interactive subtitles, tests to consolidate the material, forums for communication, tracking progress and deadlines. Elements of gamification (points, certificates) motivate learning.

The interface of gaming applications has its own peculiarities:

1. Full immersion in the game world through graphics, animations, special effects
2. Convenient character/process control on the touch screen
3. Gradual complication of levels and tasks
4. System of rewards, bonuses, in-game purchases
5. Leaderboards for competition
6. Chats or cooperative modes for socialization

Among mobile games, Brawl Stars from Supercell can be distinguished in terms of the interface. Colorful three-dimensional graphics, several modes and characters to choose from, convenient controls with adaptation to mobile devices. A system of progression through the discovery of new characters and skins. Matchmaking and team battles for player interaction.

Common mistakes when designing interfaces

Even if you follow all the recommendations and trends, it's easy to make mistakes that will ruin the user experience. Let's analyze the most common ones.

One of the main problems is that the interface does not meet the expectations and needs of the target audience. Sometimes designers get carried away with the appearance and forget about why people will use the application at all. The result is a beautiful, but incomprehensible and inconvenient app.

For example, in an app for selecting recipes by ingredients, it makes more sense to make search the main function on the start screen rather than hiding it in a side menu in three clicks. Otherwise, users will simply not understand how to get the desired result.

The other extreme is overloading the interface with functions and content. In the pursuit of multifunctionality, developers try to cram as many features as possible into a minimum of screen space. As a result, the interface turns out to be cluttered, and valuable functions are lost among the secondary ones.

Do you know the situation when you can't find the cart icon in a food delivery app among dozens of categories, promotional banners, and a search bar? That's what it is, overload. It can be solved by prioritizing elements and introducing the user to the features step by step.

The opposite problem is often encountered - insufficient information content of the interface. When in the pursuit of minimalism, all explanations and captions are removed, leaving only icons. Yes, the interface looks clean and stylish, but many users simply do not understand where to click to get the desired result. Therefore, it is better not to skimp on concise texts.

Another common mistake is inconsistent and unified interface elements on different screens. When buttons, icons, input fields look different on each page. This is very confusing, makes you spend time searching, and reduces trust in the product.

Imagine that the shopping cart in an eCommerce app is marked with a cart icon on the home screen, a bag icon in the catalog, and no text at all in the product card. Would you want to shop in such a store? I would. Recognizability, consistency, and unification are our main goals.

Finally, the scourge of many applications is insufficient testing of the interface on different device models and usage scenarios before launch. As a result, some elements may be displayed incorrectly on small diagonals, animations may slow down on weak processors, and some buttons may not work. All of this results in a lot of negative feedback and an outflow of audience immediately after the release. And it could have been avoided if we had tested everything properly.

Of course, this is not a complete list of possible mistakes, but we have analyzed the most common ones. Pay attention to the details, match your solutions with the needs of users, and don't be afraid of iterative approach. And remember: the perfect interface is not the one with nothing to add, but the one with nothing to remove.

Tools and services for prototyping interfaces

A good interface is always the result of teamwork between designers, developers, marketers, and managers. And for effective interaction, they need common tools. Let's take a look at the most popular programs and services that are used at different stages of interface design.

For creating prototypes, mockups, and interface design, they have become the de facto standard:

• Figma is a cloud-based service for collaboration between designers and developers. It allows creating prototypes, interactive mockups, and design systems. It has a large library of ready-made UI kits and plugins.
• Sketch is a desktop vector graphics editor focused on interface design. It integrates with many plugins for prototyping and exporting assemblies. It is extremely fast and convenient.
• Adobe XD is an interface and prototype editor from Adobe. It allows you to quickly create wireframes, fill them with content, link them together, and animate transitions. It has voice control.

There are services for testing the usability (UX) of interfaces:

1. Userlytics is a platform for usability testing involving real users from all over the world. It allows you to collect video feedback, perform A/B tests of prototypes, and track behavior on a website or application.
2. UsabilityHub is a service for quick testing of interfaces at the prototyping stage. You can upload a screenshot or a mockup and ask respondents to perform certain tasks or answer questions. Allows you to compare design options with each other.
3. Hotjar is a system for analyzing user behavior on a website or application. It collects heatmaps of clicks and scrolling, records sessions, allows you to survey users, and collect feedback on specific interface elements.

Designers use InVision to bring static layouts to life and make a full-fledged clickable prototype:

• InVision - an online platform for quickly creating interactive prototypes from ready-made design layouts. It allows you to make animated transitions between screens, add pop-ups, and clickable buttons. It is possible to demonstrate and collect feedback.
• Principle is a tool for detailed prototyping of animations and micro-interactions. It allows you to implement complex interactive elements such as parallax effects, animated transitions, swipes, and zooms. Designed for mobile interfaces.
• Framer is an environment for programming interactive prototypes with React. It is aimed at experienced designers who want to add complex logic and non-standard controls to interfaces.

Once the design is finalized, it's important to pass on the exact specifications to the developers. Tools can help with this:

• Zeplin is a service for transferring layouts and assemblies from designers to developers. It automatically creates specifications, style descriptions, and exports graphics in the required formats. Supports commenting and editing.
• Avocode is a cross-platform application for translating design into code. It supports more than 15 graphic file formats, allows you to quickly get information about all layers and export assemblies. It has features for team collaboration.
• Sympli is a plugin for Sketch, XD, Figma that allows you to synchronize design files with code. Automatically updates assemblies, styles, and element sizes in the project. Prevents mismatches between layout and implementation.