FreeCodingCourses
Intermediate
JavaScript

Build it free

Build a Mobile App for Free

A cross-platform mobile app built with React Native that runs on iOS and Android.
About 230 hours2 stages, 2 free courses

The short version

One codebase, two app stores. React Native lets you build a real mobile app for both iOS and Android using JavaScript, and you can learn it entirely free in about 230 hours. Start with JavaScript on Scrimba, then take Full Stack Open's React and React Native modules from the University of Helsinki. You finish with an app that runs on an actual phone, built the way modern startups build.

What you will build

  • 01A cross-platform app that runs on both iOS and Android from one codebase
  • 02Screen navigation and native UI components
  • 03A connection to a backend API for real data
  • 04An app you can run on your own phone through Expo

The path, stage by stage

Work through these free courses in order. Each stage links to the full course details, its platform, and what you walk away able to do.

StageCoursePlatformHoursWhat you gain
1. Learn JavaScriptLearn JavaScript for FreeScrimba30React Native is JavaScript, so this is the foundation. Scrimba's interactive lessons get you writing functions, working with arrays and objects, and thinking in components before you touch a phone.
2. Learn React and React NativeFull Stack OpenFull Stack Open200Full Stack Open includes a dedicated React Native module from the University of Helsinki. You learn React first, then apply it to mobile: navigation, native components, and talking to a backend. You come out with a real app on your phone.

Why these courses, not the alternatives

React Native is our pick over Swift or Kotlin for a first mobile app because one JavaScript codebase ships to both platforms, which is far more reachable solo. We start with Scrimba because its in-browser practice builds the JavaScript reflexes React Native needs. Then Full Stack Open is the standout free choice: it is a real university course (Helsinki) with a dedicated React Native part, and it teaches React properly first, which is the piece most mobile tutorials skip. Free, current, and rigorous in a way most YouTube courses are not.

Before you start

No prior mobile or JavaScript experience required. Some HTML and CSS familiarity makes the React sections easier.

What you walk away with

A cross-platform mobile app built with React Native that runs on iOS and Android.

Start with the first course

Learn JavaScript for FreeFull Stack Open

Apply it with a code-along tutorial

Frequently asked questions

What is the easiest way to build a mobile app for free?

React Native with Expo is the most beginner-friendly free route because you write JavaScript once and run it on both iOS and Android, and Expo removes most of the setup pain.

Do I need a Mac to build a mobile app?

Not to learn or to run on Android. With Expo you can test on your own phone from any computer. A Mac is only needed to publish to Apple's App Store.

Should I learn Swift or React Native first?

For a first app that reaches the most people with the least code, React Native. Learn Swift later if you want deep iOS-only performance. This path takes the React Native route.

Is Full Stack Open really free?

Yes. Full Stack Open is free courseware from the University of Helsinki, including its React Native module. You can even earn credits, though that is optional.

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Where this build leads