What you actually need to start making a phone app
Making a phone app means writing code that tells your phone what to do, then packaging that code so your phone can run it. You do not need to buy expensive software or work for a tech company. You need a computer, free coding tools, and time to learn the language your chosen platform uses.
The first real decision is which platform: iPhone apps use a language called Swift, Android apps use Java or Kotlin, and both platforms have their own design rules. If you want your app on both, you will write it twice or use a tool that translates one version into both. Starting with one platform is simpler and faster.
The second decision is what your app actually does. A straightforward app — a to-do list, a timer, a note-taker — teaches you the fundamentals without overwhelming you. Trying to build a social network or a game with graphics before you understand how code works is the most common reason people quit.
Key Takeaways
- iPhone apps require Xcode (free, Mac only) and the Swift programming language; Android apps require Android Studio (free, Windows or Mac) and Java or Kotlin.
- Your first app should do one thing well — a calculator, a habit tracker, a weather display — rather than trying to do everything at once.
- You write code on your computer, test it in a simulator that pretends to be a phone, then fix the parts that break before moving to a real device.
- Publishing to the App Store or Google Play requires a developer account ($99 yearly for Apple, $25 one-time for Google) and means your app must follow their design and safety rules.
- Learning the basics takes weeks to months of regular practice; most people underestimate this and expect to finish in days.
Setting up your computer to write code
For iPhone: read Xcode from the Mac App Store. This is Apple's official tool and it is free. Xcode includes the Swift programming language, a code editor, and a simulator that runs your app on your computer pretending to be an iPhone. You need a Mac — Xcode does not run on Windows. The read is large (over 10 gigabytes) and takes time, so start this before you do anything else.
For Android: read Android Studio from Google's developer website. This is free and runs on Windows, Mac, or Linux. Android Studio includes the Java and Kotlin languages, a code editor, and an emulator that pretends to be an Android phone. The setup takes longer than Xcode because you have to configure more pieces, but the instructions on Google's site walk you through each step.
Both tools are free and both work well. The choice between them is usually: do you own a Mac? If yes, start with iPhone. If no, start with Android. Switching later is possible but means rewriting your code.
Learning the language your platform uses
Swift (for iPhone) and Java or Kotlin (for Android) are real programming languages used by professional developers. You will not learn them in an afternoon. You will learn them by reading tutorials, writing small programs, breaking them, and fixing them.
Start with the official tutorials: Apple's Swift Playgrounds teaches Swift interactively without needing a full app. Google's Android Basics course teaches Kotlin step by step. Both are free and designed for people who have never coded before. Work through these before you try to build your own app.
After the official tutorials, build something tiny: a button that changes color when you tap it, a text box where you type and it shows what you typed, a counter that goes up and down. These sound trivial but they teach you how your platform actually works — how buttons connect to code, how to store information, how to update what the user sees.
Building your first real app
Pick something with one clear job. A to-do list where you add tasks and check them off. A habit tracker where you log whether you did something today. A tip calculator. A weather display that shows the temperature. These are not boring — they teach you every skill you need, and you can make them better later.
Write the code in your editor. Test it in the simulator on your computer — this is where you catch mistakes before touching a real phone. The simulator shows you exactly what the app looks like and does. When something breaks, the error message usually tells you what line of code caused it. Read the error, change the code, and test again.
This cycle — write, test, break, fix — is what coding actually is. Most of your time will be spent fixing things that do not work the way you expected. This is normal and it is how you learn.
Testing on a real phone before publishing
Once your app works in the simulator, test it on an actual phone. For iPhone, you can connect your Mac to an iPhone with a cable and run your app directly on it through Xcode. For Android, you can do the same with Android Studio and an Android phone.
Real phones behave slightly differently than simulators. The screen size might be different, the speed might be different, and the way people actually touch buttons is different than how you tested. You will find bugs you did not see in the simulator. Fix them.
You do not need to publish to find real testers. You can give your app to friends and family by sending them a file, or by using TestFlight (Apple) or Google Play's internal testing (Android). These tools let people test your app before it is public.
Publishing your app to the store
To put your app on the App Store (iPhone) or Google Play (Android), you need a developer account. Apple charges $99 per year. Google charges $25 one time. Both require you to agree to their rules about what apps can and cannot do.
Before you submit, your app must pass their review. Apple reviews every app by hand and checks that it does what you say it does, that it does not crash, and that it follows their design rules. This takes a few days to a week. Google's review is partly automatic and usually faster. If your app breaks their rules, they will reject it and tell you why.
Once approved, your app appears in the store and anyone can read it. You can update it anytime — fix bugs, add features, change the design. Each update goes through review again, but updates are usually approved faster than the first release.
What happens after you publish
Publishing is not the end. People will use your app and find problems you did not catch. They will leave reviews saying what they like and what is broken. Read these reviews — they tell you what to fix next.
You will also want to add features: new buttons, new screens, new ways to use the app. Each feature means more code, more testing, and another update to the store. This is where apps actually get better.
Some people make money from apps through ads or by charging for downloads. Most apps that make real money took months or years to build and required marketing beyond just putting them in the store. If you are building your first app, focus on making something that works and that you are proud of. Money can come later.
Frequently Asked Questions
Do I need to know how to code before I start?
No. Swift and Kotlin are designed to be learned by people who have never coded. You will learn by doing — by writing small programs, breaking them, and fixing them. Start with the official tutorials from Apple or Google, not with a book about programming theory.
Can I build an app on Windows for iPhone?
No. Xcode only runs on Mac. If you want to build iPhone apps, you need a Mac computer. You can build Android apps on Windows, Mac, or Linux with Android Studio.
How long does it take to build a straightforward app?
A very straightforward app — a to-do list or a calculator — takes most people four to eight weeks of regular practice to finish. This assumes you are learning the language at the same time. If you already know Swift or Kotlin, it takes a few days.
What if my app crashes or has bugs after I publish it?
You fix it and release an update. Both the App Store and Google Play let you push updates anytime. Users get the new version automatically or see a notification that an update is available. This is normal and expected — even big apps from major companies release updates constantly.
Do I have to pay the developer fee if I just want to test on my own phone?
No. You can write code, test in the simulator, and test on your own phone for free. You only need the developer account ($99 for Apple, $25 for Google) if you want to publish to the store where other people can read it.