Jinshu
jinshu.built4.fun
An immersive multilingual EPUB reader. Every word shows its CEFR level, sentences read aloud in natural voices, and looked-up words flow into a spaced-repetition deck. Tuned for e-ink.
Indie studioReading + writing apps
Small apps, made with care and a little wildness.
Built4.Fun makes polished software for people who still like to read slowly, write carefully, and keep a bit of joy in the tools they use every day.
Jinshu for multilingual reading
TeenyWriter for Chinese diary practice
Direct lifetime code for Android and E-Ink
Products
Two apps, both shipping. Each has its own home, support docs, and a clear job to do.
TeenyWriter 小小作家
writer.built4.fun
A Chinese diary-writing companion for primary-school students. Kids speak about their day; the app rewrites it into a grade-appropriate diary, then guides them through copying it onto a real grid notebook with photo-based feedback.
What we sell
One product is sold directly here. Everything else lives in the App Store, Google Play, or our Taobao store.
Jinshu Lifetime — E-Ink & Android
A one-time activation code that unlocks Jinshu Premium on up to 5 Android or E-Ink devices, forever. Includes all future updates. Ideal if you read on a Boox, Kindle Scribe-class device, or just prefer paying once.
- 5 devices, lifetime
- All future updates
- Code emailed within minutes
- 7-day refund window
After paying, you'll receive an activation code at the email used at checkout. Open Jinshu on Android, tap the paywall, choose Enter activation code, and paste it in.
iOS users: subscriptions and Lifetime are sold inside the app via the App Store. Buyers in mainland China: a CNY-priced version is available on Taobao — email us for the link.
About
Built4.Fun is a small studio. We don't try to please everyone — we make small things, with care, for ourselves and the few people who'll get them. We charge fairly when servers cost money, and stay honest about what each app does and doesn't do.
Questions, refunds, partnership ideas, bug reports — all roads lead to [email protected].