I design and build iOS and Android apps with React Native and Expo — and fully native with Swift/SwiftUI and Kotlin/Jetpack Compose when the product calls for it — from the first screen to the App Store and Google Play. These are the apps already in production, with real users on the other side. The next one could be yours.
Community & smart collars
App for finding lost pets. Users report missing or found pets on a live map and receive push notifications when one appears nearby. Includes smart QR collars that display contact info when scanned by anyone — no account needed. Available on iOS and Android.
Streaming & live TV
Streaming and news platform for Oromar TV. Includes live TV, on-demand content, rapinovelas (9:16 shorts), and news portal. Web with Next.js and mobile app with Expo.
Fintech for creators
Mobile app for managing and tracking music revenue, channels, and financial operations for content creators and MCNs. Features analytics dashboard with trend charts, balance and withdrawal management, channel performance tracking, biometric authentication, and multi-language support.
Health & wellness
Health and wellness platform based on natural remedies and herbal medicine. AI health chat (OpenAI), herb and remedy library, health journal, and personalized guidance. Web with Express + tRPC + React and mobile app with Expo.
Fitness rewards
Fitness rewards app that turns workouts into real benefits. It reads activity and heart rate from Apple Health and devices like Garmin, converts each session into points ("Drops"), and lets users redeem them for offers from 110+ partner brands by city and category. Includes weekly ranking, streaks, challenges and communities.
Hospital management
Hospital management system with patient management, appointments, medical records, and insurance handling. REST API with NestJS + TypeORM + PostgreSQL and mobile app with Expo. Features biometric authentication.
Most products win with React Native and Expo: one codebase, both stores, faster iteration. But some apps demand the platform itself — top-tier performance, the newest OS APIs, a native feel down to the pixel. I build those too: pure native iOS and Android with each platform’s latest technologies.
Apps built with Swift and SwiftUI on Apple’s latest APIs: home-screen widgets with WidgetKit, Live Activities, App Intents & Siri integration, and rich notifications.
Apps built with Kotlin and Jetpack Compose: Material You dynamic theming, home-screen widgets, and modern concurrency with coroutines and Flow.
The best of both: a React Native base with custom Swift/Kotlin modules where it counts — camera, sensors, third-party SDKs, and performance-critical paths.
Cross-platform or native isn’t ideology — it’s a per-product decision based on team, budget, timeline and what the app actually needs. I’ll recommend what serves you, and explain why.
A short call to define the core use case: who the app is for, the flows that matter, and what "done" looks like. You get a scoped proposal with timeline and price — no surprises later.
The app takes shape in weekly, visible increments — real builds on your phone from the first weeks via TestFlight and internal tracks, not mockups at the end.
Testing on actual iPhones and Androids: performance, offline behavior, push notifications, deep links and the edge cases that only show up on real hardware.
Store listings, review process and release — then over-the-air updates, analytics and iteration. The launch is the start of the product, not the end of the project.
Yes. Ramón builds cross-platform apps with React Native and Expo, so one codebase ships to both the App Store and Google Play. Pet-Meet and OromarGo are live on both stores today, and RevUp is on the App Store — real production apps, not prototypes.
Both. React Native with Expo is the default when sharing one codebase across both stores makes sense — most of this portfolio shipped that way. When the product calls for it, Ramón also builds fully native: Swift and SwiftUI on iOS and Kotlin with Jetpack Compose on Android, using the platforms’ latest APIs (widgets, Live Activities, App Intents, Material You). And in between, React Native apps with custom native modules in Swift/Kotlin for camera, sensors, third-party SDKs or performance-critical paths.
A focused mobile MVP — the core flows, working on real devices, submitted to the stores — typically ships in 4 to 8 weeks. Cost depends on scope (screens, backend, integrations like payments or push notifications), so pricing is quoted per project after a short call to define the use case. Larger products like streaming or health platforms take longer and are scoped in phases.
Yes, end to end: app signing and builds with Expo EAS, store listings, screenshots, review guidelines, and the back-and-forth with Apple review until the app is approved. Every store-published app in this portfolio went through that process with Ramón driving it.
Yes — it is one of his specialties. ArcaVida ships an AI health chat built on OpenAI inside a platform with an Expo mobile app, answering grounded in a curated remedies base. He wires the model, the backend and the mobile UI end to end.
Apps need maintenance: OS updates, store policy changes, and new features. With Expo, many fixes ship instantly as over-the-air updates without waiting for store review. Ramón offers ongoing support — monitoring, push notification campaigns, analytics, and iterating on what users actually do.
Most real apps need a backend (accounts, data, notifications) and often an admin panel or website. Ramón works full-stack: Pet-Meet, for example, is a React Native app plus a Fastify backend, a Next.js admin panel and an Astro public site, all in one monorepo — one person, no coordination overhead between separate contractors.
More than a decade shipping product across web, mobile and AI left me something more valuable than a stack: judgment. If your team is stuck on a technical decision, evaluating a stack, or wants a second opinion before sinking months into a direction — let's talk.
