Blog

Notes on
shipping software

Occasional writeups on things we hit in the field: infra, mobile, scheduling, whatever broke that week.

LFeatured
AIOpenAINode.js

LLM APIs in prod: cost, limits, and guardrails that stick

What we actually measure before shipping OpenAI-style features: tokens, retries, user-visible failures, and when to say no in the UI.

Jafrix System9 min read
RFeatured
RevenueCatExpoMobile

RevenueCat with Expo: offerings, entitlements, and TestFlight reality

A straight checklist: App Store Connect products, RevenueCat dashboard, Expo app code, and the gotchas we hit with sandbox vs production.

Jafrix System10 min read
R
React NativeMobilePerformance

React Native New Architecture: what changed in our day-to-day

Fabric, TurboModules, and fewer bridge surprises. What we had to update in libraries and when we still turned the old arch off.

Jafrix System8 min read
E
ExpoReact NativeArchitecture

Expo Router: file routes without a maze of underscores

How we lay out app/, auth, and tabs so new devs find screens in under a minute.

Jafrix System7 min read
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AITypeScriptOpenAI

Structured outputs from OpenAI: JSON your app can actually parse

Why JSON mode and schemas beat prompt-level JSON instructions, and how we validate on the server before touching the DB.

Jafrix System8 min read