PSR App Template — production Expo/React Native boilerplate

The boilerplate for sensor-measurement apps that charge money — with a DSP library validated against scipy, and a paywall where a fake subscription doesn't compile.

Ship a paid measurement app (sound level, vibration, spectrum, pitch…) on iOS and Android without spending months on the parts that get apps rejected: signal processing you can defend, App Store monetisation rules enforced by the compiler, and a PDF report engine — all wired together, all covered by 1,425 automated tests that run in plain Node.

What's inside:

• 🎛 A DSP library validated against numpy/scipy (~1e-7): FFT, real-FFT, windows, Welch PSD, spectrogram, octave bands, A/C weighting, autocorrelation pitch, RMS/peak/crest. Pure TypeScript, zero React Native imports — the scipy cross-validation fixture ships in the box.
• 💰 A paywall where a fake subscription doesn't compile: App Store Guideline 3.1.2(a) ongoing-value rule enforced at type level + runtime validator. An on-device sound meter literally cannot declare a monthly plan.
• 🛡 Anti-rejection engineering: permission minimisation, restore-purchases flow, paywall disclosure strings, plus docs/paywall-review-safety.md quoting the live guidelines.
• 📄 PDF report engine that throws if the "not a certified instrument" disclaimer is missing.
• 🌍 Ten languages from day one (en, es, pt, de, fr, it, ja, zh, ru, pl).
• 📡 Sensor wrappers that know the hardware: 48 kHz PCM mic, IMU with the Android HIGH_SAMPLING_RATE fix, GPS, barometer, documented hardware ceilings.
• 🏭 An app factory, not a starter: edit one object in app.config.ts and everything downstream derives from it. One purchase, unlimited apps.
• ✅ 1,425 tests / 28 suites, zero device required — the whole commercial and numerical core runs under vitest in Node.

Who this is for: solo devs and small teams building paid utility/measurement apps on Expo/React Native; anyone burned by an App Store rejection over subscriptions, permissions, or paywall disclosures.

Who this is NOT for: no-code makers (you need TypeScript + Expo toolchain), web/SaaS builders, ad-monetisation apps, certified medical/safety use, Expo Go (native modules need an EAS dev build).

Not included (honesty sells): Apple Developer (US$99/yr), Google Play (US$25), Expo/EAS and RevenueCat accounts; store art/screenshots or a niche idea; legal review of templates; a backend (these apps run on-device).

License: unlimited commercial apps you own, one license per person or organization, perpetual, zero royalties. You may not resell or redistribute the boilerplate itself. Full text in LICENSE.txt inside the zip.

Price: US$149 one-time. 7-day money-back guarantee, no questions asked.

Instant download (zip). Personal/organizational license as above.