Introduction Building a mobile application that handles sensitive financial data — crypto transactions, KYC verification, gift cards — means security is not an afterthought. It is a core deliverable. During the development of a cross-platform fintech application, one of the non-negotiables on the security checklist was runtime application self-protection (RASP). After evaluating our options, we
Building a Full-Stack Habit Tracker with Claude Code - Part 2: Polish, Testing & Deployment Taking the habit tracker from MVP to production-ready with categories, analytics, comprehensive testing, and Vercel deployment In [Part 1], we built a fully functional habit tracker MVP in about 6-8 hours using Claude Code as our AI pair programmer. We had: ✅ Basic CRUD operations for habits ✅ Date-based
React Native's New Architecture — JSI, Fabric, and TurboModules — has been "coming soon" for long enough that some teams wrote it off as vaporware. It shipped. It is now default in new React Native projects. And it meaningfully changes how the framework works at the performance-critical boundaries between JavaScript and native code. This post is not a getting-started guide. It is an honest account
Originally published on rohitraj.tech UPI fraud hit ₹805 cr in India last year. Cloud APIs leak data. So I built ScamRakshak — fully on-device scam detection. 3-tier inference engine: Gemma 4 LLM — context-aware classification LiteRT — fast pattern model Regex fallback — when battery low Full architecture write-up: https://rohitraj.tech/en/notes/build-on-device-ai-scam-detector-android-gemma Read
Testing Firefox Extensions with Playwright: End-to-End Testing Guide Extension testing is one of those things everyone knows they should do but few actually do. I've been using Playwright for end-to-end tests on the Weather & Clock Dashboard extension and it's changed how I think about extension quality. Unit tests don't cover the biggest failure modes: Does the extension actually load in Firefo
It's a one-line item on the roadmap. "Send a push notification when X happens." Estimate is two days, three if the backend doesn't have FCM credentials yet. There's a library for it. The library is the visible part. The other 90% is platform lifecycle, registration state machines, race conditions with navigation, payload archaeology, and a half-dozen iOS and Android quirks. Nobody writes them down
I have been building web apps for 12 years. In that time I never wrote a single line of mobile code. Not Swift, not Kotlin, not even a basic React Native hello world. That changed last month because of my wife. She has been using Synapse, the AI companion I built for her, every day from her phone browser. If you are new here, Synapse is a personal AI that uses a temporal knowledge graph instead of
The most basic concept in test doubles is the dummy. When testing a function, there are usually two kinds of input: Meaningful input Data that affects the result of the function. Dummy input Data that is required by the function, but does not affect the behavior we are testing. Below is an example of meaningful data vs dummy data. This is a calculateShipping function: function calculateShip