How a solo founder built a $20K/month Christian app in six months

Executive overview

Most solo founders stall not on building, but on picking the right idea and distributing it. Mau Baron built PrayerLock — a phone-blocking app that forces users to pray before unlocking apps — in three days using AI tools, then scaled it to $20K/month in six months with no developer, content, or ads background.

The lever was onboarding. A weak onboarding kept paid ads unprofitable; rebuilding it 3x'd conversion organically and made ads viable. Once ads worked, Spark ads on a high-performing UGC creator unlocked rapid scale.

The fastest path to $20K/month is copying a working app, obsessing over onboarding conversion, and then putting ad spend behind organic content that already converts.

App and business model

• PrayerLock blocks chosen apps until the user answers two questions and recites an AI-generated prayer
• Subscription model: $49.99/year or $9.99/week
• 58K downloads, 6.7K reviews, 4.9-star App Store rating in six months
• 43% download-to-trial conversion rate; $23.60 revenue per paying user
• Monthly revenue: $10K (Oct) → $15K (Nov) → $21K (Dec); growing 50%+ per month

Building with AI

• Cursor (Claude Sonnet) as daily coding driver; ChatGPT for questions and simpler changes; Codex CLI for complex tasks
• Do not design mockups — study the best onboarding screens in your niche and apply them directly
• Break the app into blocks; one-shot individual features or screens rather than the whole app
• Skip authentication and a database where possible — reduces friction and cost; data saved on-device
• Launched in three days; App Store approval took over a week

Organic growth playbook

• Started posting 40 times a day across 12 accounts to find what worked
• Winning format: UGC girl reaction video with an in-app demo overlay
• After 40 posts found one hook that worked — then spammed that format on TikTok and Instagram
• 10K views/day converted to 200–300 downloads/day on this optimised format
• Scaled to a second UGC creator account; combined reach got to $1.5K (July) → $2.4K (August)

Onboarding as the growth lever

• First paid ads attempt failed — optimised for downloads, not trials; onboarding was too weak
• Extended onboarding from 5 minutes to 15 minutes; longer onboarding works if it adds value and tells a story
• Rebuilding onboarding 3x'd organic conversion rate without any paid spend
• Target: 10%+ download-to-trial conversion before running paid ads

Paid ads strategy

• Started with Meta at $20/day — decent results, ~$10 per trial
• Switched to TikTok: broad campaign, US-only targeting, inserted top UGC reaction videos
• TikTok result: ~$4 per trial started; threw $4K savings in, closed October at $10K
• Found 15-year-old UGC creator Matthew whose organic videos got consistent 10K views
• Ran Spark ads on his videos: dropped to $3 per trial; threw another $6K in → $15K in November
• December: continued scaling weekly ad spend → $21K; January target: $40K
• December ad spend: ~$9K against $21K revenue; current cost per trial: $1.88

Six-step playbook for 2026

1. Find niches with apps doing $50K+/month; use Sensor Tower for revenue estimates
2. Find an app you like and improve it substantially
3. Code it in under two weeks — hard deadline to prevent endless iteration
4. Do not touch the app; obsess over distribution; post at least 20 times a day
5. Iterate on onboarding until download-to-trial conversion exceeds 10%
6. Place ad spend on organic videos already getting 10K+ views; prioritise TikTok Spark ads

Tech stack and costs

• Cursor + Codex CLI: $20/month
• ChatGPT: $20/month
• Lottie (design iteration): $25/month
• PostHog (analytics): $10/month
• Superwall (paywalls + revenue analytics): $0.20/conversion
• Singular (MMP for paid ads): $0.05/conversion after 15K free
• AWS (hosting): ~$2/month
• Google Gemini Flash 2.5 (in-app AI): ~$9/month