1. The App Store Graveyard
TL;DR > Do not write Swift or Kotlin until you have validated your app with a high-fidelity Figma prototype and a Painted Door test.
There are over 5 million apps across the Apple and Google stores. The vast majority have zero active users. Building a native mobile app is one of the most expensive and time-consuming ways to launch a startup.
$150,000
Native App Cost
The average cost to design, develop, and launch a high-quality native mobile app across both iOS and Android platforms is upwards of $150,000.
2. The Prototype Test
You can validate 90% of an app's user experience without writing code. 1. Design the core screens in Figma. 2. Link them together so they are clickable. 3. Put the prototype on a user's actual phone using the Figma Mirror app. 4. Watch them try to use it. Where do they get stuck? Where do they get confused?
Cost to Discover UX Flaws
Why you must find errors in the prototype phase.
3. The Fake App Store
To test if people will actually download it, create a landing page that looks exactly like the Apple App Store. Drive Facebook Ads to it. If 1,000 people click "Get" and it pops up a "Coming Soon" email capture, you have validated demand.
For complex multi-sided markets, the rules change entirely. Read How to Validate a Marketplace Idea.