How I built a $30K/month mobile app

Summary

John Makavoy, a self-taught developer from Scotland, built a bus and train tracking app, Mumigo, that has been downloaded over 5 million times. Through a combination of App Store Optimization (ASO), targeted keyword research, and an innovative paywall strategy, he turned the app into a $30,000/month business. John shares his journey from graphic design to coding, the challenges of building an app without prior development experience, and his growth tactics, including leveraging analytics and AB testing. His story showcases the power of persistence and solving real-world problems through technology.

Takeaways

• 😀 John Makavoy, a self-taught developer from Scotland, built a bus and train tracking app called Mumigo, which has been downloaded over 5 million times since 2017.
• 😀 Despite having no prior coding experience, John taught himself how to code by leveraging his background in graphic design and gradually building up his skills.
• 😀 The app generates $30,000 in monthly recurring revenue, primarily from subscriptions, with around 400,000 monthly active users.
• 😀 John's key strategy for growing the app involved App Store Optimization (ASO), which helped boost its visibility without spending money on ads.
• 😀 ASO strategies included targeting location-specific keywords (e.g., 'New York subway' or 'Chicago CTA') and localizing the app's metadata and screenshots.
• 😀 John used research to identify specific, low-competition keywords, allowing his app to rank higher in search results for those terms.
• 😀 A crucial step in growth was asking users for ratings at key moments, such as when they could see real-time bus or train tracking on the map.
• 😀 The pandemic led John to pivot from ad-based revenue to a subscription model, which contributed to the app's sustained growth.
• 😀 AB testing was critical to refining the app's onboarding process and paywalls. By testing different versions, he increased the conversion rate from 0.5% to 8%.
• 😀 John's tech stack includes Laravel for the backend, Adobe Creative Suite for UI/UX design, and Mixpanel for event-based analytics, which helped drive growth.
• 😀 John's advice for new app developers is to solve a problem you're personally passionate about and rely on data (such as event-based analytics) to drive informed decisions and growth.

Q & A

Who is John Makavoy and what did he create?

John Makavoy is a self-taught developer from Scotland who built an app called Mumigo, a bus and train tracking app covering over 160 cities, which has been downloaded more than 5 million times.

How much revenue does John’s app generate?

Mumigo generates around $30,000 in monthly recurring revenue, primarily through subscription-based income.

What inspired John to create his app?

While working for a bus company in Edinburgh, John wanted a way to see buses moving on a map—similar to Uber’s live taxi tracking—so users could avoid waiting in the rain at bus stops.

What was John’s background before becoming a developer?

John began his career as a graphic designer and gradually became curious about coding, exploring JavaScript, backend systems, and databases before teaching himself app development.

Which technologies and tools were used to build Mumigo?

John initially used Xamarin with C# .NET, then later rebuilt the app using Swift for iOS and Flutter for cross-platform development. The backend runs on Laravel PHP, and he uses tools like Mixpanel, Cloudflare, and Lottie for animations.

What was the key strategy that led to Mumigo’s growth?

App Store Optimization (ASO) was the main strategy. John used location-specific keywords, localized screenshots, and keyword testing to boost visibility in app searches, leading to millions of downloads at no cost.

Can you summarize the three main steps John used for App Store Optimization?

Step 1: Add city-specific keywords and localized screenshots. Step 2: Research effective keywords using Apple Search Ads or search suggestions. Step 3: Request app ratings at ‘golden moments’ within the app to improve ranking.

How did John pivot his business model during the pandemic?

When ad revenue dropped during the pandemic, John shifted to a subscription model, introducing premium features and optimizing paywalls through A/B testing to increase conversions and revenue.

What major insights did John gain from using event-based analytics?

Event-based analytics allowed John to understand user behavior and optimize onboarding and paywalls effectively. This data-driven approach increased conversion rates from 0.5% to 8%.

What advice does John offer to aspiring app developers in 2025?

John advises developers to solve a real problem they personally face to stay motivated and to rely on data from event-based analytics rather than vanity metrics like active users to drive meaningful growth.

What are some of the main operating costs for Mumigo?

The largest expenses are server costs—about $2,500 per month across 20 dedicated servers—and third-party API fees, including mapping services, which cost around $1,000 per month.

How did the updated onboarding and paywall design improve Mumigo’s success?

John simplified onboarding to quickly show app value, introduced social proof, and implemented multiple pricing options. The introduction of a 'reverse trial' (free week after closing the paywall) significantly increased conversions.