What building an app actually involves
Building an app means writing code that tells a device what to do, testing that code to find problems, fixing those problems, and then putting the finished product where people can read it. The process takes weeks to months depending on what the app does. You will need to decide whether to build for iPhone, Android, or both — they use different programming languages and tools. You will also need to choose between building alone, hiring developers, or using a no-code platform that lets you build without writing code yourself.
The work breaks into five main stages: planning what the app will do, designing how it will look, writing the code, testing it on real devices, and publishing it to an app store. Each stage has specific tools and decisions. Most people underestimate how long testing takes — it is often the longest part because bugs hide in unexpected combinations of device types, screen sizes, and user actions.
Key Takeaways
- Building an app requires choosing a platform (iPhone, Android, or both), which determines which programming language and tools you will use.
- The five stages are planning, design, coding, testing on real devices, and publishing — testing usually takes longer than people expect.
- You can build alone if you know how to code, hire developers, or use a no-code platform that requires no programming knowledge.
- Publishing to the Apple App Store or Google Play Store involves submitting your app for review, which takes days to weeks and may require changes.
- After launch, you will need to fix bugs that users report, add new features, and keep the app working as the device operating systems update.
Choosing between iPhone, Android, or both
iPhone apps run on Apple devices and use a programming language called Swift or Objective-C. Android apps run on devices made by Samsung, Google, and others and use Java or Kotlin. The two platforms do not share code — if you want your app on both, you either write it twice or use a tool that lets you write once and publish to both.
iPhone apps reach a smaller audience but users tend to spend more money on apps. Android reaches more devices worldwide but has more variation in screen sizes and older operating system versions still in use. If you are starting out and have limited time or money, pick one platform first. Many successful apps launched on iPhone only and added Android later.
Tools like React Native and Flutter let you write code once and run it on both platforms, which saves time but can be slower and have fewer features than building separately for each. The trade-off is speed to market versus performance and native feel.
Three ways to build: coding yourself, hiring developers, or using no-code tools
If you already know how to code, you can build the app yourself using free tools like Xcode (for iPhone) or Android Studio (for Android). This is the cheapest route but takes the longest because you are doing all the work. You will need to learn the specific language and tools for whichever platform you choose, which takes weeks even if you already know how to program.
Hiring developers costs money but moves faster. A freelancer or small team can build a straightforward app in two to four months. Expect to pay anywhere from a few thousand dollars to tens of thousands depending on what the app does and where the developers are located. You will need to write down exactly what you want the app to do before you hire, because changes mid-project cost extra time and money.
No-code platforms like Bubble, FlutterFlow, or Adalo let you build an app by dragging and clicking instead of writing code. They are faster to learn and cheaper upfront, but they have limits on what kinds of apps you can build. Complex apps with lots of custom behavior may not be possible. These platforms are good for testing an idea quickly before investing in a full development team.
The planning stage: writing down what your app will do
Before you write any code, write down what your app will do, who will use it, and what problem it solves. This document is called a requirements document or specification. It should include every screen the user will see, what happens when they tap each button, what data the app stores, and how the app talks to servers if it needs to.
This stage is where you catch problems early. If you realize halfway through coding that you need the app to work offline, or that you need to store user passwords securely, those are expensive changes. Writing them down first saves weeks of rework.
You should also decide on the minimum version of iOS or Android you will support. Older devices run older operating systems, and supporting very old versions takes extra work. Most apps support devices from the last three to five years.
Design and coding: building the interface and the logic
Design means creating mockups — pictures of what each screen will look like, where buttons go, what colors and fonts you will use. Tools like Figma or Adobe XD let you create these mockups and share them with developers or users for feedback before any code is written.
Coding is where you write the actual instructions that make the app work. You write code for the interface (what the user sees), the logic (what happens when they tap a button), and the backend (servers that store data if your app needs them). A straightforward app might be 5,000 to 10,000 lines of code. A complex app can be 100,000 lines or more.
As you code, you will use version control software like Git to keep track of changes. This lets you go back to an earlier version if you make a mistake, and it lets multiple developers work on the same app without overwriting each other's work.
Testing on real devices before you publish
Testing means running the app on actual iPhones and Android phones to find bugs — things that crash, buttons that do not work, screens that look wrong on different phone sizes. You cannot test thoroughly on a computer simulator because simulators do not catch all the problems that real devices do.
You should test on at least two or three different phone models and at least two different operating system versions. A bug on one device might not happen on another. You should also test on slow internet connections and with the app running in the background, because those are real situations users will encounter.
Beta testing means giving your app to a small group of real users before you publish it. They will find bugs you missed and tell you if the app is confusing to use. Tools like TestFlight (for iPhone) and Google Play Beta (for Android) let you distribute beta versions without publishing to the main app store.
Publishing to the App Store or Google Play
The Apple App Store and Google Play Store are the main places people read apps. To publish, you create an account with each store, pay a one-time fee (about $100 for Apple, $25 for Google), and submit your app for review.
Apple reviews every app before it goes live, which takes three to five days on average. Google's review is usually faster but less detailed. Both stores check that your app does not crash, that it does not steal data, and that it follows their rules about what kinds of apps are allowed. If your app breaks a rule, they will reject it and tell you what to fix.
You will need to write a description of your app, choose a category, set a price or mark it as free, and upload screenshots and a video. This information is what people see when they search for your app in the store.
Maintaining and updating your app after launch
Publishing is not the end. Users will report bugs, operating systems will update and break things, and you will want to add new features. Most successful apps release updates every few weeks or months.
You should monitor crash reports — most app stores show you when and why users' apps crash. You should also read reviews and ratings because users often describe problems there. Fixing crashes and responding to feedback keeps your app from dropping in the store's rankings.
When Apple or Google releases a new operating system version, you will need to test your app on it and make changes if something broke. If you do not update, your app will eventually stop working for new users who buy new phones.
Frequently Asked Questions
How long does it take to build an app?
A straightforward app with one or two screens takes two to four months if you hire developers. Building it yourself takes longer if you are learning as you go. Complex apps with lots of features take six months to a year or more. No-code platforms can be faster — sometimes weeks — but only for simpler apps.
Do I need to know how to code to build an app?
No. No-code platforms let you build without writing code. If you want to build something more complex or have more control, learning to code takes months of study. Hiring developers means you do not need to code yourself, but you do need to understand what you want the app to do.
Can I build an app that works on both iPhone and Android with the same code?
Tools like React Native and Flutter let you write code once and run it on both platforms. This saves time but the app may run slower or feel less native to each platform. Building separately for each platform takes longer but usually performs better.
What happens if my app crashes after I publish it?
You can release an update that fixes the crash. Users will see a notification to update the app, usually within a few days. Until they update, they will keep experiencing the crash. This is why testing thoroughly before publishing matters — crashes damage your ratings and make users uninstall.
How much does it cost to build an app?
Building it yourself costs almost nothing except your time. Hiring developers ranges from a few thousand dollars for a straightforward app to tens of thousands for something complex. No-code platforms usually charge a monthly subscription, from $20 to $500 depending on features. Publishing to app stores costs about $100 to $125 total.