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I Built a $100K/Month Android App
Steve and his co-founder had both completed major personal weight loss journeys. Steve himself dropped 45 kilograms (100 lbs) by religiously tracking his daily calorie intake. Having used almost ev...
https://www.youtube.com/watch?v=0pp4X58q_0s
I Built a $100K/Month Android App

TL;DR: Steve bootstrapped his AI calorie tracking app, Journalable, from under $1K to $100K+/month in 18 months by defying conventional wisdom and prioritizing Android over iOS. Leveraging Google App Campaigns and a 10x target CPA budget rule, he built a highly profitable, friction-free subscriber flywheel with nearly 1 million downloads.

The Founder’s Story

Steve and his co-founder had both completed major personal weight loss journeys. Steve himself dropped 45 kilograms (100 lbs) by religiously tracking his daily calorie intake. Having used almost every competitor app on the market, Steve grew deeply frustrated with their high complexity and tedious database searching.

To solve this friction, he built Journalable—an AI-powered calorie counter and nutrition assistant that allows users to log meals using natural language sentences or photos. As a bootstrapped founder with limited budgets, Steve analyzed the market data and realized that while the developer community is hyper-saturated on iOS, Android presented a massive, cheap customer acquisition opportunity. By focusing on the Play Store, he scaled Journalable to over 30,000 active paying subscribers and $100K+/month in under 18 months.

The Building Process

Journalable’s core value proposition is extreme, friction-free simplicity. Calorie tracking is historically tedious. Journalable completely removes the traditional food-database search UI:

  • Text Tracking: A user types a conversational sentence (e.g., “yogurt, granola, blueberries, and almonds”). OpenAI’s API transcribes the text, breaks down the ingredients, extracts individual macro distributions, and calculates the total count in a second.
  • Photo Tracking: A user takes a photo of their plate. The app identifies the ingredients and portion sizes, outputting the exact calories and macros.
  • Vibe Coding Tooling: Steve relies heavily on AI-assisted development, utilizing Claude Code and Claude Co-work ($100/mo) alongside GitHub Copilot and CodeRabbit to handle the codebase rapidly, allowing them to remain a tiny, high-leverage team.

The Google App Campaign Blueprint

While iOS is widely viewed as the premium app marketplace, Steve’s marketing strategy centers on exploiting Android Arbitrage:

  • The Cost-to-Conversion Disconnect: RevenueCat’s 2025 State of Subscription Apps Report showed that while iOS users are four times more expensive to advertise to than Android users (higher CPMs), they only convert at 20% better rates.
  • Cheaper Budgets, Organic Spillover: Running ads on Android proved highly cost-effective and created a natural “spillover” effect, driving organic searches and downloads on iOS. Today, 80% of Journalable’s subscribers are on Android, and 20% are on iOS.

Steve’s 5-Step Paid UA Playbook

  1. Deep Attribution & Tracking Setup: Configure deep event measurement. You must track and report every install, paywall hit, free trial start, purchase, and purchase value back to Google Ads. Google’s machine learning algorithms cannot optimize delivery without this signal.
  2. Launch Install Campaigns: Run baseline install campaigns to feed the algorithm data. Flood the setup with the maximum allowed assets: 10 text pieces (5 headlines, 5 descriptions) and 20 images + 20 videos (using stock media is fine to start).
  3. The Asset Optimization Phase: Give campaigns time to learn. Start with a tiny budget ($10 to $15/day). Ramps up slowly, swapping stock files for custom creatives. Take big swings (wildly different text hooks or visuals) rather than making minor design tweaks.
  4. Deploy Target CPA (tCPA) Campaigns: Once assets have baselines, launch a Target CPA campaign. You must adhere to the 10x CPI Budget Rule: if a trial or purchase costs you $15, you must set your daily campaign budget to at least $150/day. Google’s algorithm requires a minimum of 10 conversion events per day to optimize successfully.
  5. AGGRESSIVE Store & Product Optimization: Because Google’s App Campaigns auto-generate creatives using your Google Play Store listing, you must constantly optimize your store screenshots, title, description, and keywords (using ASO tools like AppTweak). Concurrently, test paywalls and pricing structures to push subscription conversions upward, allowing you to scale campaign budgets safely.

The Tech Stack

  • Backend & Cloud Infrastructure: Google Firebase, Google Cloud Platform (GCP), BigQuery, Google Play Store
  • Subscription Management: Revenue Cat (1% transaction fee)
  • AI Core Backend: OpenAI API
  • Development & Automation: Claude Code ($100/mo), OpenAI Premium ($20/mo), GitHub Copilot ($39/mo), CodeRabbit ($30/mo), N8N (operations automation, $24/mo)
  • Customer Support: Fixer (AI email support, $30/mo)
  • ASO & Marketing: AppTweak ($180/mo), Google Ads ($500K all-time spend, operating at 100% break-even ROI to feed organic and subscription growth)
  • Web: Webflow ($18/mo)

Key Quotes & Metrics

  • MRR & ARR: $80,000 MRR ($125,000 in past 28 days), tracking at nearly $1 million ARR.
  • Downloads: Almost 1 million downloads on Android.
  • Subscribers: 30,000+ active paying subscribers (40,000 total).
  • Platform Distribution: 80% Android / 20% iOS.
  • The Android Opportunity: “iOS apps have been released at 5x the rate of Android apps recently, leading to heavy saturation on iOS. The easiest opportunity is finding successful iOS apps that don’t have an equivalent on Android and building them.”

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