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Hi, I'm Feryael Justice

Android & Full-Stack Developer

I craft efficient, secure and scalable apps, from Jetpack Compose to full-stack web. Based in Mallorca, Spain.

4+
Years coding
6+
Shipped apps
5+
Core stacks
About me

Building for mobile, web and beyond

Fernando González Serrano

📍 Mallorca, Spain

My name is Fernando González Serrano, but everyone calls me Fer or Feryael Justice. I started programming at 15, exploring web development and desktop software, and never stopped building since.

Most recently I worked as an Android Developer at ExisTI, a tech consultancy, on a banking app, building it from scratch and migrating a legacy version, alongside a great team in a large company like NTTData.

Along the way I've shipped desktop enterprise software with Delphi at Tec-Soft, and full-stack web products with Laravel, Vue.js, Node.js and TailwindCSS. My passion is creating efficient, secure and scalable applications, and growing on impactful projects.

4+

Years coding

6+

Shipped apps

5+

Core stacks

Selected work

Projects I've shipped

From native Android apps to full-stack platforms, real products, real users.

Signal Vault
In development
E2E EncryptedWeb + Android + iOS PlatformsSTOMP Real-time

Signal Vault

A secure, end-to-end encrypted messaging and vault app available on all platforms. Spring Boot + JPA backend, STOMP for real-time messaging, a Next.js web client with TanStack Query, Web Crypto API for client-side encryption, native Android with Jetpack Compose and native iOS with SwiftUI.

  • Spring Boot
  • JPA
  • STOMP
  • Next.js
  • TanStack Query
  • Web Crypto
  • Kotlin
  • Jetpack Compose
  • SwiftUI
Vince Pro Shop - Web
Stripe PaymentsAI + ML Built-inJWT Auth

Vince Pro Shop - Web

Full-stack e-commerce for a billiards store on Node.js: React (Next.js) + Express, MySQL, VPS on Debian. Secured with JWT and bcrypt, custom admin panel, Stripe checkout, an AI chatbot and ML-powered product suggestions.

  • Next.js
  • React
  • Express
  • MySQL
  • Stripe
  • AI/ML
Vince Pro Shop - Mobile
In development
KMP Shared codeiOS + Android PlatformsMaterial 3 Design

Vince Pro Shop - Mobile

The mobile companion for Vince Pro Shop, built with Kotlin Multiplatform + Compose Multiplatform for both iOS and Android. Clean architecture with Koin, SQLDelight, Ktor, Room, Datastore, CredentialManager/Keychain, Material 3 and Stripe.

  • Kotlin
  • KMP
  • Compose
  • Ktor
  • Stripe
MiraiLink
Compose Native UIClean Arch ArchitectureExpress Own backend

MiraiLink

A social app designed for anime and video-game fans, with its own Express.js backend. Native Android built with Jetpack Compose, MVVM, Hilt, Version Catalog and Clean Architecture.

  • Android
  • Kotlin
  • Compose
  • Hilt
  • Express
Compound Interest Master
Vico ChartsUnit tests TestedStateFlow Reactive

Compound Interest Master

An app that helps you understand and calculate compound interest simply. Built with Jetpack Compose, MVVM, Hilt, Clean Architecture, StateFlow, Coroutines, unit testing, Material 3 and Vico charts.

  • Android
  • Kotlin
  • Compose
  • Hilt
  • Testing
Super Snake Game
Firebase LeaderboardGoogle Sign-in2D Game

Super Snake Game

Relive the classic Snake with a 2D style and more. Compete for your high score! Built with Jetpack Compose, MVVM, Hilt, Firebase, Credentials, Google Sign-in and Clean Architecture.

  • Android
  • Kotlin
  • Compose
  • Firebase
Super News App
Retrofit NetworkingSOLID PrinciplesMVVM Pattern

Super News App

Your favourite news app, built with Jetpack Compose, MVVM, Hilt, Version Catalog, SOLID principles and Retrofit for API calls.

  • Android
  • Kotlin
  • Compose
  • Retrofit
Hotel Aura de Mallorca
Weather API Booking logici18next MultilingualSocket.io Realtime

Hotel Aura de Mallorca

A hotel website (React + Express) with a weather API that decides booking availability based on local conditions. Uses Axios, QR codes, React Calendar, i18next, Google reCAPTCHA, Socket.io, cryptography, Nodemailer and Helmet.

  • React
  • Express
  • Socket.io
  • i18next
Feryael Dev
YouTube ChannelAndroid Topics

Feryael Dev

My programming YouTube channel, showcasing mobile projects and knowledge across different Android topics.

  • YouTube
  • Android
  • Content
Career

Where I've worked

~2 years of professional experience

  1. Dec 2024 – Jun 2025 · 6 months

    Android Developer (Junior)

    ExisTI

    Tech consultant focused on Android. Collaborated on a banking app with NTTData, building 5+ new features with Kotlin, Jetpack Compose, Hilt, MVVM and Retrofit, and shipping secure builds with Proguard/Dexguard.

    • Kotlin
    • Compose
    • Hilt
    • Retrofit
  2. Sep 2023 – Aug 2024 · ~1 year

    Fullstack Web Developer

    Homerti

    Maintained and developed internal web products with Laravel and Vue.js, in an Agile team using Bitbucket for version control. Started as a higher vocational training internship (Sep–Dec 2023).

    • Laravel
    • Vue.js
    • Agile
  3. May 2022 – Aug 2022 · 4 months

    Software Developer

    Tec-Soft

    Developed enterprise software in Delphi Seattle for desktop environments, including tooling such as PDFBuilder.

    • Delphi
    • Desktop
Tech arsenal

The stack I build with

Tools and technologies I use daily across mobile, web and backend.

Mobile / Android

  • Kotlin
  • Jetpack Compose
  • Android
  • Kotlin Multiplatform
  • Swift / iOS
  • Material 3
  • Hilt / Koin

Frontend / Web

  • React
  • Next.js
  • Astro
  • Vue.js
  • TailwindCSS
  • JavaScript / TS

Backend / Data

  • Node.js
  • Express.js
  • Laravel
  • MySQL
  • Ktor
  • REST APIs

Architecture & Tooling

  • Clean Architecture
  • MVVM / MVI
  • Coroutines
  • Retrofit
  • Firebase
  • Stripe
  • AI / ML
Contact

Let's build something together

Open to new opportunities and collaborations. The fastest way to reach me is by email.

nano9gs@hotmail.es