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jcellomarcano/README.md

Hi there, I'm Jesús Marcano 👋

🚀 About Me

I am a Senior Software Engineer and Mobile Architect with over 9 years of experience orchestrating high-performance applications across Fintech, HealthTech, Entertainment, and Marketplaces.

Currently, I operate as a Digital Nomad / Autónoma based in Barcelona, Spain. I approach software engineering with the same discipline I learned as a professional Cellist: prioritizing structure, harmony between modules, and precise execution.

I am currently the Lead Android Engineer for the Messaging Domain at Leboncoin (France's largest marketplace), where I focus on scaling communication architecture for 10M+ users.

  • 🔭 Current Tech Focus: Migrating legacy native apps to Kotlin Multiplatform (KMP) and building autonomous agents using Claude Sonnet 4.5, Gemini 3.0, and the Google Antigravity agent tool.
  • 🤝 Collaboration: I specialize in bridging the gap between Mobile Clients (State management, UI) and Backend AI Logic (Python, LangChain).

🛠 The Tech Stack

Mobile & Multiplatform Kotlin KMP Android Swift Flutter Jetpack Compose

AI, Data & Backend Python LangChain Gemini Claude GraphQL Haskell

IoT & Hardware BLE NFC


💼 Featured Experience

🟠 Leboncoin (Marketplace) | Current

  • Role: Senior Android Engineer (Messaging Ownership).
  • Impact: Leading the architectural migration of the Messaging module to a standalone ecosystem. Achieved a 40% reduction in response latency through coroutine and thread optimization.

🟣 Parallel Digital (AI & Tech)

  • Role: Senior Software Engineer.
  • Impact: Built AI-informed chatbots using Python & LangChain for customer service. Developed backend functionalities using Haskell and Appwrite.

🔵 Butterfly Network (HealthTech)

  • Role: Senior Android Engineer.
  • Impact: Upgraded critical medical imaging systems to Kotlin 1.9 and Apollo GraphQL. Implemented RIBs architecture for modularity in a handheld ultrasound device app.

🔵 Venmo / PayPal (Fintech)

  • Role: Senior Android Engineer.
  • Impact: Developed the Cryptocurrency feed and "Shared Accounts" features. Led Accessibility (TalkBack) initiatives to support visually impaired users.

🟢 TouchTunes (Entertainment)

  • Role: Senior Android Engineer.
  • Impact: Integrated Google Pay and managed complex audio states for over 65,000 interactive jukeboxes in bars/restaurants.

👨‍💻 Beyond the Code

I believe that great engineering requires a balance of technical rigor and creative passion.

  • 🎻 The Musician: I am a trained Cellist (Simon Bolivar Conservatory). I also enjoy creating musical arrangements and am currently learning Piano. Music taught me that "synchronization" isn't just a thread concept—it's how teams succeed.
  • 🌌 The Jedi: Huge Star Wars fan. I'm fascinated by the lore, the technology, and the philosophy. This is the way.
  • ✈️ The AvGeek: Passionate about Aviation. I love planes and the engineering marvels that keep them in the sky.
  • The Fan: Loyal supporter of FC Barcelona (Barça). Visca el Barça!

🗣️ Languages

I am a language enthusiast. I believe learning new languages rewires the brain just like learning new code paradigms.

  • 🇺🇸 English: Professional Working Proficiency (C1)
  • 🇪🇸 Spanish: Native
  • (CAT) Catalan: Professional Working Proficiency
  • 🇩🇪 German: Next Goal (In Progress)
  • 🇫🇷 French: Future Goal

📈 GitHub Stats



📫 Let's Connect

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  1. MaferMazu/willy-language-interpreter MaferMazu/willy-language-interpreter Public

    Lexer, Parser.

    Python 1 1

  2. parakeet-repository parakeet-repository Public

    Test doing a PokeAPI with Flutter

    Makefile

  3. Foody Foody Public

    Kotlin

  4. TheFlagStationbusTerminal TheFlagStationbusTerminal Public

    Gention para Terminal la bandera

    Kotlin

  5. FearlessBirthHeuristic FearlessBirthHeuristic Public

    Kotlin

  6. iAlbumSeeker iAlbumSeeker Public

    Kotlin