Most designers dream of creating products that rise to the top of the App Store charts. But to do so, it’s vital to design them to meet high expectations for quality and functionality. Human Interface Guidelines (HIG) is a must-read resource for anyone who wants to master an ios app design. By reading HIG, you will gain in-depth information about this OS.

In this article, I want to provide a summary of the essential design principles and specific design recommendations from HIG for iOS designers.

Design principles

In HIG, Apple defines the following five basic principles of ios app design:

Consistency

A consistent app uses consistent visual and functional language. In general, elements with similar functions should look similar. Consistency creates a sense of familiarity and simplifies the process of interaction with an app for first-time users.

Feedback

Feedback acknowledges actions and shows the results of any operations. Feedback is what keeps people informed. iOS designers have multiple ways of providing feedback— visual feedback on tapping, progress indication for activities that take some time, and audio feedback for notifying users about certain operations.

visual of a progress indicator
Progress indicator shows current progress and remaining time. Image by Adrien Gervaix.

Metaphors

An interface metaphor is a UI visual that leverages knowledge users already have from real life. Metaphors allow users to learn more quickly because they can use the knowledge gained from the real-world when interacting with digital products. The most famous metaphor in human-computer interaction and UX design is Alan Kay’s “desktop metaphor”. The desktop metaphor moved us from typing command to direct manipulation with digitally rendered objects.

screenshot of 1984 Mac OS
The original 1984 Mac OS desktop that popularized the new graphical user interface.

Direct manipulation

Users experience direct manipulation when they use gestures to interact with on screen content. Direct manipulation helps users see immediate results of their actions.

clipart of scrolling interaction
Scrolling interaction on mobile. Image by artrayd

User control

iOS puts people, not the system, in control. Good iOS design prevents users from making mistakes by suggesting a course of action, but it should never push users in making certain decisions.

contextual tips in slack
Contextual tips in Slack

Interface essentials

iOS app design guidelines define three key elements of app experience:

Bars

Bars tell people where they are in the app (status bar), provide navigation (tab bar), allow them to search for information (search bar), or take some actions (toolbar).

Views

Views contain the primary content people see in the app. Text, visuals, animations, interactive objects – all those elements are located in views.

Controls

Controls initiate actions (buttons) and convey status/information (progress indicators).

Design recommendations

iOS is a large platform, and it’s impossible to provide all possible design recommendations in a format of a single article, but still, it’s possible to provide a few of the most important recommendations that mobile designers should remember:

Don’t hide the notch

The notch, sensor housing, is an element that prevents iOS screen from being edge-to-edge. It might be tempting to hide the notch area with a black bar to create a complete square screen, but it’s better not to do it. Why? There are a couple of reasons for that:

  • You make the screen look smaller than it really is. The area of the notch provides the sense of space for the content to be displayed. For example, if you use a Google map in your app, it won’t suffer by being clipped by the notch.
iPhone XS map feature
Google Map on iPhone XS
  • By hiding notch, you make your app look inconsistent with other iOS apps.

Design using points not pixels

Pixels are the smallest physical element that we can control on a digital display. The more pixels can be fitted into a specific screen size, the higher the PPI (pixels-per-inch), and the clearer the rendered content becomes. Points, on the other hand, are a resolution-independent measurement. When the original iPhone was introduced, both points and pixels were the same (320×480 pixels = 320×480 points), but the situation changed with the release of the first iPhone with a retina screen. Depending on the screen pixel density, a point can contain multiple pixels (e.g., 1 pt contains 2 x 2 pixels on a regular retina display).

When you are designing for modern iOS devices, you should think in points, but design in pixels. To make your app look good on every screen, you should prepare design assets in 3 different resolutions (1x, 2x and 3x).

If possible, use single, system typeface

Typography plays a vital role in any digital product, and iOS app design is not an exception. When it comes to selecting a typeface for your app, it’s recommended to use a system typeface of iOS. The system font of iOS is called San Francisco. The fonts of San Francisco are optimized to give your text unmatched legibility, clarity, and consistency.

It’s important to know that when using a system font, you will have access to dynamic type, which lets the font adjust based on the user’s preference.

Avoid clipping content by corners

All recently released iPhones have one thing in common – they feature a display with round corners and notch. Round corners and notch can clip the content. When designing screen layouts, always use a safe area layout guide to push the content to the point where it won’t be clipped. Generally, 16 points are enough to make the proper margin. Also, the system includes predefined layout guides that make it easy to apply standard margins around content, but you can always define custom layout guides.

visual of safe area on iPhone
Illustration of the safe area for iPhone X. Image by Apple.

Include status bar in as many places as you can

Mobile design should be glanceable. Ideally, it shouldn’t take more than just a glance to get all important information. Users rely on the status bar for important information such as current time, signal, battery.

Use vibrant colors to bring out interactive elements

Vibrant colors are a simple yet powerful way to direct the user’s attention to a particular UI element. Vibrant color works equally well on the white and dark background. But don’t go too overboard with vibrant colors in your UI. Ideally, only 10% of your design should have vibrant colors.

visual of blue buttons on iPhone
Using vibrant blue to highlight an active option.

Optimize for thumb

Tiny touch targets located too close to each other can make the interaction really painful for users. What can make things even worse, is when users have to stretch their fingers in order to interact with them.

To create really comfortable user interactions, both the size and location of interactive elements should be in a thumb-friendly zone. When working on your iOS app design, aim to have a minimum tappable area of 44pt x 44pt for all controls. It will guarantee comfortable interactions for your users. 

Make your navigation visible

The latest iPhone models feature a relatively large screen, and it means that you can use it to create a better navigation experience. Avoid using hidden navigation patterns such as a hamburger menu and ‘use tab bar instead’ option. Tab bar is always visible and won’t cause users to ask, “Where am I?” This pattern is also located in the thumb-friendly zone, which makes the interaction more comfortable for users.

Here are a few tips for tab bar design:

  • Add labels for icons. Clear labels will simplify the process of navigation for first-time users. Adding labels is especially important for less known icons.
  • Use color to convey the status of the navigation option. The color will help users understand what option is active right now.
options bar on iPhone
The active option in tab bar is colored in contrasting color.

Use motion to convey hierarchy and facilitate understanding

Clarity is an essential characteristic of a well-designed iOS app. Modern iOS apps can be really complex and contain a dozen different screens. And when users navigate from one screen to another, they need to understand how the screens are related. Good motion language can help to create a connection between screens and will help users understand the spatial transitions.

One important thing to remember when working on animation in your app is that you need to make it look consistent with system built-in animations. A consistent animation will look familiar for users and will keep them engaged.

Minimize interruptions

Users don’t like to be interrupted, especially when they are in the middle of something important. That’s why it’s recommended to keep in-app alert dialogs to a minimum and create a clear exit for every dialog.

Support Dark Mode in your app

In iOS 13.0 and later, people can use a dark system-wide appearance called Dark Mode. Dark Mode enhances visual ergonomics by reducing eye strain when device is used at night or in dark environments. In Dark Mode, iOS uses a darker color palette for all screens, views, menus, and controls.

If you want to support Dark Mode in your app, you should test your design in both light and dark appearances. See how your interface looks in both appearances and adjust your design as needed to accommodate each one.

Always preview your design in an Emulator

Before sending your design to a real device, you should always preview it in an emulator. You can see and interact with your design using the XCode iPhone emulator.

Conclusion

The first iPhone was released more than a decade ago. If you compare the first iPhone with the iPhone 11, you will see the progress Apple made along the way. The same progress we have in the process of design & development for the iOS platform. Human Interface Guidelines and provide essential information about the requirements for the modern iOS app. And large iOS designers & developers communities on Stackowerflow will help you find an answer to specific questions.