I design, build and publish iOS and Android apps with React Native and Expo, and fully native in Swift or Kotlin when the product calls for it. One senior engineer end to end: from the first screen to Apple review, with real builds on your phone from week two. 13+ years shipping software, the last 7 focused on mobile. Scope and price closed before we start.
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, with no account needed. Available on iOS and Android.
AI interview coach
AI interview coach that turns your resume, job description and STAR stories into a digital twin. Ask a question by voice and get an answer written in your own material, in several lengths (30s, 60s, executive, technical, STAR), plus mock interviews, scored voice practice and a Zero-Glow live copilot for real interviews. Expo app for iOS and Android over a Python backend with speech-to-text and LLM routing.
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. On the first call I tell you which one fits your product, with numbers: cost, timeline, and what you gain or give up either way.
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 recommend what serves your budget, even when it means less work for me, and I explain why.
A free 30-minute call to define the core use case: who the app is for, the flows that matter, and what "done" looks like. You leave with a scoped proposal: timeline, price and what is out of scope. No surprises later, no cost if you decide not to go ahead.
The app takes shape in weekly, visible increments: real builds on your phone from week two via TestFlight and internal tracks, not mockups at the end. You see progress every week, so nothing gets built for six weeks in the wrong direction.
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, screenshots, Apple review and release, then over-the-air updates, analytics and iteration. You own the code, the accounts and the keys from day one. The launch is the start of the product, not the end of the project.
No agencies in the middle, no account manager relaying messages: you talk to the person writing the code, from the first call to the first release.
Get my app quotedRamón has been shipping production software since 2012, more than 13 years, and has worked on mobile since 2019: React Native bridge apps at Desarol, then senior full-stack mobile developer at NativApps, and lead React Native developer for a mobile team in Madrid. The apps shown here are the most recent ones, released between 2024 and 2026; the experience behind them is far older than those release dates.
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, and 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 free 30-minute call to define the use case. You get scope, timeline and a fixed price in writing before anything starts, with no cost if you decide not to go ahead. 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.
You do. The repository, the code and the store accounts are published under your name and stay yours, so you are never locked to one developer. Ramón can keep maintaining the app afterwards, but that is a choice, not a dependency, and he signs an NDA when the project needs one.
Send me two or three lines about your idea: what the app does, who it is for, and when you need it in the stores. I reply with the questions that are missing and we book a 30-minute call, free and with no commitment. If your project is not a fit for me, I tell you on that same call.
WhatsApp or email, with whatever you have: an idea, a Figma file, or an app that already exists and needs a rebuild.
We define the core use case, what belongs in version one, and what can wait for version two.
Scope, timeline and price in writing. If you say yes, we start that same week.
