The archive · Consumer Apps · Product decision · 2024–2026
Cat Flashlight's AI-built bet: ¥1 app tops China's paid chart in 4 hours, ~¥400k earned
A no-code solo developer used Cursor AI to build a selfie fill-light app in an hour; the ¥1 Pro version topped China's App Store paid chart and earned ~¥400k.
Cat Flashlight (小猫补光灯)
What the business is
An iPhone app that turns the screen into a bright colored fill light for selfies and videos — preset colors, brightness control, split-screen color temps and a Live mode — with a ¥1 Pro version adding dynamic effects.
Starting capital：Roughly US$99/year for the Apple developer account; no paid marketing (developer story via i5z.net).
How it started
Chen Yunfei (花生), an ex-big-tech manager with no coding background who quit in 2023, took his girlfriend's suggestion and spotted Xiaohongshu users relying on solid-color images for fill light. Using Cursor AI he built the MVP in under an hour and submitted it; Apple approved it the next day (36Kr via c114, 2026-05-22).
What happened
His 'I made an app with AI' Xiaohongshu post went viral off the controversy, driving 30k+ downloads from one post; he iterated on user feedback and, after copycats appeared, shipped the ¥1 Pro version within about two weeks. Downloads rose the day after the app started charging, and the Pro hit #1 on the paid chart within 4 hours.
How it ended up
Still live and profitable for a solo developer: ~300k–500k downloads per app and ¥300–400k Pro revenue by May 2026; Chen turned down 10+ investor approaches and moved on to an open-source 'Nuwa Skill' project adopted by Tencent, Kimi and Zhipu.
Background
Cat Flashlight (小猫补光灯) is a one-purpose iPhone app that turns the screen into a bright, colored fill light for selfies and video, with preset colors, brightness control, split-screen color temperatures and a Live mode. It was built in under an hour by Chen Yunfei (花生), a former big-tech manager with no coding background, using the Cursor AI coding tool — a demo of 'vibe coding' as a solo business.
The idea came from his girlfriend and from Xiaohongshu, where users posted with solid-color images as makeshift light panels. Chen validated the habit, shipped the free app in 2025, and posted an 'I made an app with AI' note on Xiaohongshu; the controversy drove 1M+ reads, 80k likes and tens of thousands of downloads, with about half of readers downloading the app.
After copycats appeared, Chen added a ¥1 Pro version within about two weeks. Charging did not slow downloads — they rose the next day — and the Pro hit the top of China's App Store paid chart within 4 hours of launch. By May 2026 the two apps had roughly 300k–500k downloads each and the Pro had earned about ¥300–400k; more than ten investors approached and were turned down.
What has to be true
- The product matched an existing behavior (solid-color light panels) instead of inventing a new one, so the first post had an audience ready to convert.
- Building with AI cut the idea-to-App-Store cycle to about a day, letting one person iterate on feedback and ship a paid version within two weeks.
- Making the ¥1 charge itself a story gave the pricing a viral hook, and downloads rose the day after charging began.
- Solo ownership let the developer say no to ten investors and keep a ¥300–400k revenue stream as a side business.
What can be applied
AI collapsed build time, not risk: the win came from a habitual need and a controversy-driven launch — the one-hour build was the last mile; demand and distribution carried the run.
Aftermath
As of May 22, 2026, Chen had two live apps with ~300k–500k downloads each and Pro revenue of about ¥300–400k; he declined investment and continued as an independent developer. He has since built and freely licensed an open-source project, 'Nuwa Skill' — a tool that packages a person's thinking style into AI-invocable 'skill packs' — which he says Tencent, Kimi and Zhipu's AI products have adopted. The Cat Flashlight apps remain available on the App Store.
Sources
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