The first mobile phone was envisioned in 1917 by a Finnish inventor Eric Tigerstedt but its conception came to fruition in 1983 when Martin Cooper of Motorola launched DynaTac 8000x for commercial use. Over the next two decades, mobile phones progressed - getting more features and most importantly becoming smaller with better battery life over time.
However, a revolutionary breakthrough came in January, 2007 when Apple launched their first iPhone coupled with a suite of 500 mobile applications (apps) available to download from its App Store. Apple sold over 11.6 million iPhones in just under a year! Over time, mobile phones came to be called smartphones given that their processing power has eclipsed even supercomputers of the past!
In this blog post, we are going to cover the basics of smartphones, mobile applications, how they are developed and how to recruit talent focused on mobile app development. Let's get started!
What are Mobile Applications?
In simple terms, a Mobile Application is a software running on a Smartphone utilizing its features and computing power in a creative way to enhance user experience. Smartphones just like computers run on an operating system (OS) and at present the two biggest ones are: Google’s Android and Apple’s iOS operating system.
To build a mobile application a mobile developer uses either Android Studio Integrated Development Environment (IDE) provided by Google or Xcode Software Development Kits (SDKs) provided by Apple. The programming languages used are Kotlin and Swift respectively.
Their relevance can be shown by the massive revenue they generate worldwide. According to a Statista report, in 2024 global mobile app downloads will cross 200 billion!
What is required to publish an app on Google play or Apple Store?
Once a mobile app is ready for customer use then it can be published on the Google play or the Apple Store for users to download. On the Android ecosystem it is possible to download apps from other "App stores" besides Google's Play Store but the Google Play Store is by far the largest option. On the other hand on iOS, the Apple App Store is the ONLY way to download an app.
There are some common steps which need to be taken before the app becomes available for the customer:
- Creating developer account on Google Play or Apple Store
- Preparing App content based on guidelines
- Creating App store listing for your app
- Uploading App bundle
- Publishing the app
More details on how the app publishing process works is available here: How to publish on App Store , How to publish on Google Play
How do you develop mobile applications?
In general, there are two types of application development - Native and Progressive Web/Hybrid/Cross platform app development. Native apps are developed in sandboxed environments of iOS and Android using the tools and programming languages provided by the respective platforms.
Progressive Web and Hybrid apps mostly use Web Technologies for their development. They are installed on smart devices like native apps and have similar look and feel but use different web development tools and web programming languages available.
To understand the difference between Native and Non-Native app development, let’s dive deep into each one of their development processes.
Native App Development:
Native apps operate in sandboxed environments created for them. They can utilize all the features and capabilities present in the hardware of the device. The performance and support for native apps is unparalleled as the documentation, tools, frameworks, programming languages and developer support are all created by the same entity which has made the operating system as well as the hardware of the smart device.
Google and Apple also ensure backward compatibility so with any updates of their OS, working apps on their platforms will generally not break. Therefore, if done correctly the development cycle of native apps is streamlined with minimal chances of failure.
Some of the main features of native apps are:
- Codebase in one programming language utilizing the operating system’s capability to provide robust performance
- Superior functionality as native apps can use smart devices’ hardware and software
- App capable of functioning in offline mode
- UI/UX design is the same as the in-built operating system apps and any update relating to the visuals of the OS is automatically applied to the native apps.
- Easy bug prevention and App crashes as there are breakpoints provided by the native tools which can be used to go through line-by-line of all code.
- Automatic inclusion of all screen ratios and sizes for targeting different types of Apple and Android devices available.
- Testing frameworks in build with tools like Xcode, Android Studio
- Security against potential hacks due to sandboxed environment
- Community support as Apple and Google provides access to their own developers for brainstorming sessions
When should you build native apps:
- When the application depends on performance or on device hardware like GPS, Camera etc.
- When the priority is to give rich user experience and interactions with the application
- When there is a need for the application to grow in functionality, reduce latency and add new features based on iterative versions.
Progressive Web App (PWA) Development:
Progressive web apps are application programs that reside on a remote server and delivered to the end user via the internet through a browser interface. Hence, they require internet connectivity at all times and are built using web programming languages and tools. They are called progressive web apps since they are websites designed and targeted to be specifically viewed on smart devices. They can have a similar look and feel as Native apps.
Some of the features of Progressive Web Apps are:
- Fast and Cheap development and deployment
- Easy customization and maintenance as only one codebase
- Code reusability as on one codebase can be used for deploying multiple apps
- Cross platform deployment since all smart devices have web browsers
- No need for installation as they reside on a web server
- Can be easily accessed through various platforms like desktop, laptop or mobile without being published on App Stores
When should you decide to build a Progressive Web App:
- Ease of access of the app is a priority, since a web app can be shared and installed via a link
- When your app’s core functionality primarily focuses on engaging user with showing content in the form of text, images and video
- When the intended product needs many versions over a short period of time
Hybrid/Cross Platform App Development:
Hybrid apps are an amalgamation of native components and web components. They reside as a lightweight container in the device which allows them to access certain device hardware like Camera, GPS essential to providing a good user experience.
They also require internet connectivity for the most part since major functionality of the app resides on the backend. For connecting with the backend to pull data and UI/UX visuals every hybrid app uses a WebView provided by the native platform to show content of the app. This WebView calls a HTTPS link at the launch of the app and shows the various UI/UX elements built using HTML5, CSS and JavaScript.
Some of the features of Hybrid Apps are:
- Short development time and Cost Effective since codebase can be reused for different smart devices running on respective operating systems
- Multiple platform support as same code can run on iOS and Android
- Scalability is easy to achieve as iterative builds will run on all platforms
When should you decide to build Hybrid Apps:
- Target audience will have internet access while using your application
- Shorter deployment time to test run a prototype or see proof of concept
- Performance issues can be masked by the light weight nature of the application
- The application is not using 3D animations or video processing
- When a combination of web and native features are required for the intended use of the application
The following table summarizes and further simplifies the choice between native and non-native application development:
And a flowchart which can further simplify the choice between Native and Non-Native app development:
What technologies are used for building mobile apps?
A mobile development technology stack consists of three main components for building the targeted application:
- Programming Languages - Coding language used by Mobile Application Developer to build the target application.
- Toolkit - Full Feature Environments made for application development
- SDK - Software Development Kit refers to the sandboxed environment provided for application development
The following table shows the different stacks for native and non-native app development:
Why should I hire a Mobile Developer?
The primary way many customers interact with a product is now mobile. This is even more true in the developing world where access to laptops/desktops is limited but mobile phones are ubiquitous. Most businesses will need a customer facing mobile product even if they have an online presence due to following reasons:
- Accessibility - Reaching global audience using wide variety of mobile devices
- Brand Recognition - A good mobile application can spread brand awareness and increase brand loyalty through specific offers and products
- Payment Portals & In-App Purchases - An easy way for retail & service industry to take payments from their customers
- Customer Engagement - Stats show that customers spend more time on company’s mobile app versus website
- Social Media Integration - A way to freely market your company’s brand and increase its loyalty by constant social engagement
Even if you need a mobile app, you might wonder why dedicated mobile developers are needed? Why can't the engineering team that builds the web product also build the mobile product? Here is why:
- Different platforms: Mobile app development typically requires knowledge of specific platforms, such as iOS or Android, which may not be possessed by a web development team.
- Different programming languages: Mobile app development often requires knowledge of different programming languages than web development, such as Swift or Kotlin, which may not be known by a web development team.
- Different design considerations: Mobile apps have different design considerations than web products, such as screen size and touch input, and may require expertise in mobile-specific design principles.
- Different user experience: Mobile apps have different user experience than web products because of their different form factor and the way users interact with them.
- Different testing and optimization: Mobile apps need to be tested and optimized differently than web products, as they are operating on different platforms and devices.
Overall, while a web development team may be able to build a mobile app, a dedicated mobile development team may be better equipped to handle the unique challenges of mobile app development and deliver a high-quality product.
What are the different parts of mobile app development?
A successful mobile app project consists of following parts:
- Prototype
- Storyboarding
- UI/UX design
- Data Exchange
- Testing
- Version Control
- Metrics
Prototype
Mobile devices provide many restrictions due to their screen size, computing power and memory, therefore prototyping becomes an essential component of any mobile application development as it sets do’s and don'ts, can’s and cants based on customer requirements.
Storyboarding
A storyboard is a UI layout of the application depicting the flowchart of user interactions and the changes in the Model-View-Controller (MVC) setup.
UI/UX Design
Design of a mobile application is as important as its functionality. A good design ensures user engagement by having a smooth flow between different components of the application and having a similar look and feel of device’s in built applications. Another goal of a good UI is to support different screen sizes of the same platform, for eg. iOS runs on iPhone, iPad, Apple Watch with different versions and screen sizes, so UI has to build assets which change when being viewed on these devices. Lastly, UI also ensures localization of image and text so that the app can be published in various languages.
Data Exchange
This part of the application development process is related to the client-server model. In this the frontend interacts with the backend of the app to request and response data from servers or cloud which is to be shown in the app. This is done through making API calls. Application programming interfaces (APIs) are a way for one program to interact with another. API calls are the medium by which they interact. An API call, or API request, is a message sent to a server asking an API to provide a service or information. The four most basic request API calls are:
- GET: To retrieve a resource
- POST: To create a new resource
- PUT: To edit or update an existing resource
- DELETE: To delete a resource
Testing
Testing becomes crucial to ensure that the user has a high quality bug free experience.
Version Control
Every living or in development app needs to be built iteratively. Version control helps in synchronizing the team members with the current development and also the published version of the application. GitHub is a popular version control scheme available for native and hybrid application development.
Metrics
Most successful apps rely on customer engagement and feedback and metrics provided by Apple and Google or 3rd parties is essential in building and maintaining a successful mobile application. Some of the popular analytics tools are Google Analytics, Apple Analytics, Localytics, Mixpanel etc.
What are in-app purchases?
In-app purchasing refers to the buying of goods and services from inside an application on a mobile device, such as a smartphone or tablet. In-app purchases allow organizations to provide their applications for free but then monetize the application with subsequent purchases down the line. The company then advertises upgrades to the paid version, paid feature unlocks, special items for sale, or even ads for other apps and services to anyone who downloads the free version. This allows the organization to profit despite giving the basic app itself away for free.
Sensor Tower intelligence report shows that Apple’s App Store is projected to generate $41.5 billion in consumer spending globally from in-app purchases, subscriptions, and premium apps and games in the first half of 2021. This is about 1.8 times the revenue generated by Google Play, which saw an estimated $23.4 billion in the same period. Here are the main ways to monetize a mobile app:
In-App Advertising:
Customers are hesitant about making in-app purchases and the moment the app owner asks to pay, they tend to uninstall it. Another tactic for app monetization is through in-app advertising.
The app needs an extensive user base and sufficient user behavioral data to place highly targeted ads. One of the best examples of apps using the In-App Advertising model is Instagram – it brought in $18.6 billion in annual ad sales in 2021!
Subscriptions:
Here, the app (and some of its content) is free to use, but users need to buy a subscription on a monthly or yearly basis to access premium content or advanced features.
A great example of an app using this model is Headspace. It has more than 65 Million downloads and generated $100 million revenue per year from paid subscriptions. And the expected revenues for the coming years are anticipated between $100 and $150 million, as per NPR.
Freemium with In-App Purchases:
This is one of the best app monetization strategies - by offering the app for free and allowing users to purchase a wide range of digital add-ons within the app. These elements can be anything – game currency, extra lives, or premium app content.
Though this monetization model is used mainly by game applications (for example, PUBG, Clash of Clans, and many others), it is also prominent in non-game apps. One of the apps using this monetization model is Tinder – the highest-grossing non-game app of 2021 globally!
How are mobile apps tested?
As the term suggests, Mobile App Testing refers to the process of validating a mobile app for its functionality and usability before it is released publicly. Testing mobile apps helps verify whether the app meets the expected technical and business requirements and provides a great user experience.
For successful mobile app testing, teams need to test apps across numerous screen resolutions, operating system versions, and distinct network bandwidths. This helps ensure that the app performs flawlessly across numerous device configurations when released publicly. At a high level, testing mobile apps includes the following:
- Testing apps performance across distinct OS versions (for example Android 7.0, 8.0, etc)
- Testing apps appearance in both Portrait and Landscape mode
- Validating apps compatibility and performance when operated on specific settings
- Testing whether the app is compatible with mobile sensors like Gyroscope, Accelerometer, GPS, etc.
- Testing the app’s GUI (Menus, dropdown, navigation buttons, etc) for functionality
Some of the major categories include:
- Installation Testing - Testing whether the app installs with all inherent features
- Functional Testing - Verifying all components of the app work in tandem with the initial requirements
- Compatibility Testing - Testing if the application can run under different mobile devices and browsers
- Localization Testing - Testing whether the app shows appropriate language and country specific information
- Input Testing - Testing based on given user inputs and outputs which the mobile app must handle like gestures, voice inputs and sensor inputs
- Storage Testing - Storing and retrieval of data from local storage of the app and from server
- Interruption Testing - Testing how the app handles interruption of network, push notifications, incoming call, SMS etc.
- Performance Testing - Application performance in peaks and lows of mobile connectivity (3G, 5G and Wifi)
- Security Testing - Testing app data security to uncover vulnerabilities, threats and risks and mitigating them
What do technical interviewers look for in mobile developers?
It is helpful to know what technical interviewers look for in a mobile developer and the most commonly asked questions. As a recruiter, you can help prepare a candidate for the screens and also get a sense of how confident they are about the subject matter.
Examples of some questions include:
Hard Skills
Programming Languages
- What are constructors and destructors, explain their use?
- What is the difference between Objective C and Swift
- How do you extend a class in Swift and Kotlin?
- What are the control transfer statements used in Swift?
- What is NullPointerException in Kotlin?
- What does an Elvis operator do?
- What are different threads in ReactNative?
- What is Redux and how are its components used in ReactNative?
- What is a bridge and how is it used for both iOS and Android in ReactNative?
- What are the components of Angular?
- What is the difference between AOT and JIT compilation in Angular?
- Explain the lifecycle hooks in Angular?
- Explain MVVM architecture in Angular?
- What is the difference between Xamarin.Forms and Xamarin Native?
Design
- Explain Singleton, Delegate and Observer design pattern?
- How will you manage UI elements and different screen resolutions between iOS, Android and Hybrid apps?
API’s & Frameworks
- Explain iOS & Android frameworks?
- How to achieve concurrency in Swift and Kotlin?
- What is the difference between Ionic, PhoneGap and Cordova frameworks?
Databases
- Explain Core Data?
- How does LocalStorage work in Kotlin?
Client/Server
- Explain how you will make asynchronous REST calls to the server and store the results?
- How is parsing done in Swift, Kotlin, ReactJS and AngularJS
Behavioral Skills / Soft Skills
- Examples of Mobile apps you have developed?
- Explain the methodology you use before writing code?
- Explain the different components of Android, iOS and Hybrid App?
- Personal example wherein the development cycle was blocked due to a bug and what role did you play in solving it?
- Which type of app development platform will you recommend for our organization?
- How do you keep up with the latest trends in App development?
- Is Progressive Web App the future of App development?
- What questions will you ask a client for transforming an idea into an app?
- Which parts of the app development process excite you the most?
What’s the best way to find mobile developers?
LinkedIn remains the best place to look for developers, at least in the United States and Canada. Their Recruiter search has several fields you can use to search candidates, including title, location, current company, years of experience etc. and by creating a boolean the search can be narrowed down.
A quick search on recruiter portal of LinkedIn shows almost 250k results globally when narrowing by title alone:
However, titles alone aren't sufficient when searching for mobile developers as many mobile developers have a generic software engineer title but mention iOS or Android skills in their profile. Using such as approach increases the results by 4X.
In addition to searching yourself on LinkedIn, here are some other ways to find and engage with mobile developers:
- Job boards - Careerbuilder, Upwork, LinkedIn, Dice, Monster, Workable, SimplyHired, Glassdoor, Remoteok.io (Remote), Craigslist (freelance) and Ladders, to name a few. Job boards will typically yield more active candidates vs. the higher-quality passive candidates on LinkedIn, but they can still be a good source.
- Staffing companies - you can utilize staffing companies like Rocket, RobertHalf, Randstad and others to help you find a proficient Mobile developer.
- AI sourcing - you can use tools like Hireflow or Fetcher to source Mobile developers for you to engage.
What is the compensation range for mobile app developers?
According to Comparably, the salaries of mobile developers in the US range from $31,000 to $261,000 , with a median salary of $106,500.
What are the growth projections for mobile app developers?
According to zippia.com, projected job growth for mobile app developers is 21% from 2018-2028. As can be expected the demand for developers with mobile skills is also very robust making the war for mobile talent particularly fierce.
About Rocket
Rocket pairs talented recruiters with advanced AI to help companies hit their hiring goals and knows technology recruiting inside out. Rocket is headquartered in the heart of Silicon Valley but has recruiters all over the US & Canada serving the needs of our growing client base across engineering, product management, data science and more through a variety of offerings and solutions.
