BuildBrief: The apps with 1 feature beat the apps with 50 features. Here's why

Your mobile app has 12 features.

Your competitor's app has 1 feature.

Guess who's winning?

Spoiler: Not you.

Here's the brutal truth: every feature you add to a mobile app makes it worse, not better.

The platform changes the rules completely.

Why mobile apps must be simple

Mobile screens are tiny. Attention spans are even smaller.

People open your app on the go, between meetings, in line at the grocery store, while walking their dog.

They don't have time to learn complex interfaces or navigate through multiple tabs.

They need to open your app, solve one problem, and close it.

That's it. That's the entire job.

If your mobile app tries to do everything, it does nothing well.

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Web apps can be complex:

People sit at desks with large screens and keyboards. They have time and focus. They expect power tools with lots of options.

Notion, Figma, Airtable - these are power tools. They have dozens of features because desktop users need them.

Mobile apps must be simple:

People use phones while doing something else. They're distracted, in a hurry, or looking for a quick solution.

The best mobile apps solve exactly one pain point with one core feature.

Examples:

• Uber: Get a car to your location. That's it. Not trip planning, not social features, not ride reviews at the core. Just "get me a car now."
• Venmo: Send money to a friend. Everything else is secondary. The core action takes 3 taps.
• Shazam: Identify this song playing right now. One button. One purpose. Perfect execution.

Notice the pattern: Each app does ONE thing so well that alternatives feel complicated.

Before building your mobile app, answer this question:

"What is the ONE problem someone opens my app to solve?"

If you can't answer in one sentence, your app is too complex.

If your answer has the word "and" in it, you're building two apps.

Bad answers:

• "It helps people track habits AND journal AND set goals"
• "It's a social network AND marketplace AND messaging app"
• "It does budgeting AND investing AND bill tracking"

Good answers:

• "It helps people split bills with friends instantly"
• "It blocks distracting websites during work hours"
• "It reminds you to drink water throughout the day"

The simpler your answer, the better your app will perform.

How to build a one-feature mobile app

Step 1: Identify your core action

What is the single most important thing users do in your app?

Everything else is noise. Cut it.

Step 2: Make that action instant

How many taps does it take to complete your core action?

If it's more than 3-5 taps, you're losing users.

Optimize the path:

• Remove unnecessary screens
• Skip optional inputs
• Pre-fill what you can
• Save preferences
• Make defaults smart

Step 3: Hide everything else

Your app probably needs settings, profiles, and other features.

But users shouldn't see them unless they look for them.

The 80/20 rule:

• 80% of screen real estate = core feature
• 20% = everything else (tucked away in menus)

Step 4: Test with the 5-second rule

Hand your phone to someone who's never seen your app.

Ask them: "What does this app do?"

If they can't tell you in 5 seconds, your interface is too cluttered.

Action steps

1. Write down your core feature in one sentence. If you can't, simplify your concept.

2. Map your core action flow. Count the taps. If it's more than 5, start cutting.

3. Audit your screens. Delete any screen that doesn't directly support your core feature.

4. Test the 5-second rule. Show your app to 3 people and see if they instantly understand it.

The best mobile apps aren't built by adding features.

They're built by removing everything that doesn't matter.

If you're ready to build your app idea and get it live in the App Store...

then click here to get started!

Happy building!
– Kristoffer, BuildWithAI