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iOS & ANDROID APPS · BOOKING NEW PROJECTS

Your app live on both stores in 4 to 8 weeks.

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.

EXPERIENCE13+ years shipping · mobile since 2019
APPS7 built end to end
STORES3 live on App Store · Google Play
DELIVERYMVP in 4–8 weeks · fixed quote
Get my app quoted Send the brief by email
  • Top Rated on Upwork
  • 100% Job Success
  • Apps in production with real users
  • English / Español · GMT-5
Pet-Meet, app screenPet-MeetCommunity & smart collarsIntervatar, app screenIntervatarAI interview coachOromarGo, app screenOromarGoStreaming & live TVRevUp, app screenRevUpFintech for creatorsArcaVida, app screenArcaVidaHealth & wellnessSudApp, app screenSudAppFitness rewardsMenonita Health, app screenMenonita HealthHospital management
PROOF · SHIPPED WORK

7 apps, real users on the other side.

Not concepts: products in production
Pet-Meet, app screen 1Pet-Meet, app screen 2
№ 01SHIPPED 2026Live in stores

Community & smart collars

Pet-Meet

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, and a friend network. Available on iOS and Android. Around the app: an Astro public site with shareable deep-link pages for pets, reports and collar activations, and the collar admin dashboard listed separately as Pet-Meet Admin, all in one Turborepo monorepo.

React NativeExpoNext.jsAstroFastifySupabaseDrizzle ORMTurborepoAWS S3Twilio
App StoreGoogle Playwww.pet-meet.com
See how it was built
Intervatar, app screen 1Intervatar, app screen 2
№ 02BUILT 2026In beta testing

AI interview coach

Intervatar

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.

React NativeExpoTypeScriptReact NavigationReanimatedPythonOpenRouterDeepgramexpo-iapi18next
See how it was built
OromarGo, app screen 1OromarGo, app screen 2
№ 03SHIPPED 2026Live in stores

Streaming & live TV

OromarGo

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.

Next.jsExpoBunny CDNClerkOneSignalRevenueCatWordPress
App StoreGoogle Play
See how it was built
RevUp, app screen 1RevUp, app screen 2
№ 04SHIPPED 2024Private / enterprise app

Fintech for creators

RevUp

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.

React NativeExpoTypeScriptReact QueryNativewindFormiki18nextAxios
See how it was built
ArcaVida, app screen 1ArcaVida, app screen 2
№ 05SHIPPED 2026Private / enterprise app

Health & wellness

ArcaVida

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.

ExpresstRPCReactExpoMySQLTiDBDrizzle ORMStripeOpenAI
arcavida.vercel.app
See how it was built
SudApp, app screen 1SudApp, app screen 2
№ 06SHIPPED 2025Live in stores

Fitness rewards

SudApp

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.

React NativeExpoTypeScriptApple HealthGarmin
App StoreGoogle Playwww.sudapp.co
See how it was built
Menonita Health, app screen 1Menonita Health, app screen 2
№ 07SHIPPED 2025Private / enterprise app

Hospital management

Menonita Health

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.

NestJSTypeORMPostgreSQLExpoAWS CognitoRedis
See how it was built
CROSS-PLATFORM & NATIVE

React Native when it fits, fully native when it matters.

The right tool for your product, not for my resume

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.

01§

Native iOS

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.

SwiftSwiftUIWidgetKitLive ActivitiesApp Intents
02§

Native Android

Apps built with Kotlin and Jetpack Compose: Material You dynamic theming, home-screen widgets, and modern concurrency with coroutines and Flow.

KotlinJetpack ComposeMaterial YouCoroutinesFlow
03§

Native modules in React Native

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.

React NativeSwiftKotlinTurbo Modules
04§

An honest technical call

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.

ArchitectureTrade-offsRoadmap
HOW WE WORK TOGETHER

From idea to the stores, in four moves.

One senior engineer, end to end

  1. Discovery

    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.

    ScopeTimelineFixed quote

  2. Design & build

    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.

    React NativeExpoWeekly builds

  3. Real-device QA

    Testing on actual iPhones and Androids: performance, offline behavior, push notifications, deep links and the edge cases that only show up on real hardware.

    TestFlightDevice testingPush & deep links

  4. Launch & beyond

    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.

    App StoreGoogle PlayOTA updates

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 quoted
FAQ

Questionspeople actually ask.

Hiring, AI, MVPs & how I work
01

How long have you been building mobile apps?

Ramón 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.

02

Do you build apps for both iOS and Android at the same time?

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.

03

Do you only work with React Native, or also native iOS and Android development?

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.

04

How long does it take to build a mobile app, and what does it cost?

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.

05

Do you handle publishing to the App Store and Google Play?

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.

06

Can you integrate AI into a mobile app?

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.

07

What happens after launch?

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.

08

Do I also need a backend or a web version? Can you build those too?

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.

09

Who owns the code and the App Store and Google Play accounts?

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.

START YOUR APP

Tell me about your app. I’ll tell you what it costs and how long it takes.

Guayaquil, Ecuador · GMT-5 · English / Español

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.

  1. You write to me

    WhatsApp or email, with whatever you have: an idea, a Figma file, or an app that already exists and needs a rebuild.

  2. 30-minute call

    We define the core use case, what belongs in version one, and what can wait for version two.

  3. Closed proposal

    Scope, timeline and price in writing. If you say yes, we start that same week.

WhatsAppLinkedInUpwork
  • Free, no commitment
  • Fixed quote per project
  • The code and the store accounts are yours
  • NDA on request