María del MarCardona
I'm María del Mar Cardona — a software engineer with a strong focus on mobile development, full-stack product engineering, and building tools that help people create. I enjoy taking ideas from a sketch to a polished, shipped product, owning every step of the journey: UX, architecture, code, analytics, delivery and iteration.
My work is deeply influenced by music. My personal brand, Seikilos, comes from the oldest surviving complete musical composition. Its message — “As long as youre alive, shine” — is a reminder to create with purpose and never postpone what matters. That philosophy guides how I write software: intentionally, creatively and always learning.
I've built everything from native iOS apps and React Native products to full-stack web platforms, educational tools, BI systems and custom internal software. Whether I'm designing a mobile experience or architecting backend integrations, I aim for clarity, simplicity and long-term maintainability.
Experience
My Work Experience
My Work Experience
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Freelancer Software Developer
September 2021 - Present
Design, build, and maintain production-grade web and mobile applications for clients and personal products. Lead end-to-end development—from architecture and database design to UI implementation and deployment—using React Native, Expo, SwiftUI, UIKit, Next.js, Laravel, Supabase, MySQL, PostgreSQL, and cloud-based CI/CD pipelines.
Experience includes developing feature-rich mobile apps, optimizing performance across iOS/Android, implementing secure authentication flows, and shipping continuously through modern DevOps tools. -
Computer Science Teacher
September 2022 - September 2024
Taught advanced modules in databases, software architecture, and applied programming fundamentals at a public vocational center. Designed practical, industry-aligned coursework focused on SQL, relational modeling, API integration, and hands-on technical projects.
Mentored students in developing professional-quality applications and helped modernize the department's technical curriculum. -
Business Analyst
September 2019 - September 2022
Delivered data-driven solutions for public-sector and enterprise clients using MicroStrategy, Power BI, and MySQL. Led requirement-gathering, dashboard design, and data-modeling initiatives to support high-stakes decision-making. Built interactive desktop and mobile BI applications, automated reporting workflows, and collaborated with multidisciplinary teams to translate business needs into actionable technical implementations.
Initially hired as a junior analyst, I quickly became the point person for modernizing mobile dashboards thanks to my experience developing apps, and was promoted to team lead within two years, driving quality standards and mentoring new analysts.
Portfolio
Skills & Stack
Skills & Stack
End-to-End Product Engineering
I design, build, and ship mobile-first products, taking ideas from first prototype to production. My focus is on React Native and Expo, but my experience spans everything from backend APIs and databases to CI/CD pipelines, analytics and in-app monetisation.
My flagship project is Melodista, a fully self-built music creation app that combines chord generation, AI-assisted songwriting and a scalable Supabase backend with subscription billing through RevenueCat.
Mobile & Frontend
- React Native & Expo
- Expo Router, React Navigation
- TypeScript / JavaScript
- SwiftUI & Objective-C (iOS)
- Responsive UI & design systems
Web & Backend
- Next.js & React
- Laravel / PHP
- REST APIs & integration
- Authentication & security flows
Data & Analytics
- PostgreSQL & MySQL
- Supabase & Firebase
- MicroStrategy & Power BI
- Product & usage analytics
Tooling & DevOps
- Git & GitHub
- EAS, Vercel, CI/CD
- RevenueCat, Google Mobile Ads
- App Store & Play Store delivery
Ways I Like to Work
- Ownership from UX to release
- Performance and accessibility awareness
- Incremental delivery and continuous testing
- Close collaboration with designers & product teams
Projects
Selected Work
Selected Work
Melodista – AI-Powered Songwriting Companion
Melodista is my flagship mobile app: a music creation companion that helps songwriters generate chord progressions, explore harmonies and overcome writer’s block. Built end-to-end with React Native, Expo, Supabase and RevenueCat, it includes AI-assisted lyrics, progression playback, multilingual support and subscription monetisation.
I own the complete lifecycle: UX, architecture, implementation, analytics, CI/CD, and App Store / Play Store delivery.
React Native & Expo
Expo Router, TypeScript
Supabase (PostgreSQL, Auth, Storage)
RevenueCat Subscriptions
Analytics & in-app experiments
Seikilos – Code, Music & Time
Seikilos is my personal brand and developer identity, hosting my portfolio and experiments at seikilos.es.
The name comes from the Seikilos epitaph, the oldest surviving complete musical composition from Ancient Greece. Its message, “As long as you're alive, shine, don't be sad at all; life is short, time asks for its due”, resonates deeply with how I approach both music and software: create, iterate and ship while you can.
As a developer closely connected to music and inspired by artists and history, Seikilos represents the intersection of craft, creativity and time-limited opportunity.
Personal dev blog & portfolio
React / Bootstrap experiments
Multilingual web projects
Design systems & UI explorations
Teaching, Native Apps & Backend Projects
Udemy Instructor – Java & Swift (2016–2019)
Created and published online courses on Java and Swift programming, focusing on fundamentals, hands-on exercises and empowering new developers.
Chemistry App – Inorganic Formulation (2014)
At 17, I built an Objective-C iOS app helping students practise inorganic chemistry formulation. The app was repeatedly featured by Apple and widely used in schools. Though deprecated today, it was my first complete native app and marked the beginning of my journey as a developer.
Python Data Processing System
Developed a Python data-processing platform for a company needing to unify information scattered across several internal databases and external program APIs. The system automated data extraction, transformation and validation to produce management dashboards and provide deeper insight into accounting, KPIs and operational performance.
Recycling Game Backend – Junta de Andalucía
Implemented the backend for an educational recycling video game using Laravel and MySQL. Created REST APIs, admin tools, and user progress storage to support a gamified learning experience.
Desktop Tools for a Dance School
Built two desktop apps: one for accounting & financial control and another for managing student assessments. Improved their workflow efficiency and reduced dependency on manual spreadsheets.
Recycling Game Backend – Junta de Andalucía
Implemented the backend for an educational recycling video game using Laravel and MySQL. Created REST APIs, admin tools, and user progress storage to support a gamified learning experience.
Desktop Tools for a Dance School
Built two desktop apps: one for accounting & financial control and another for managing student assessments. Improved their workflow efficiency and reduced dependency on manual spreadsheets.
Full-Stack Client Platform (React & Next.js)
Built a full-stack web platform under NDA using React and Next.js, exposing both public pages and an authenticated area for internal users. Implemented server-side rendering, protected routes, API routes for business logic, integration with external services and a relational database, plus role-based access to dashboards and management tools.
Web applications (React & Next.js)
Developed a web applications with React and Next.js, focused on performance, SEO and maintainability. Implemented dynamic routing for blog and landing pages, added analytics, tracking pixels and custom forms, and set up CI/CD for fast, safe deployments.
Education
My Education
Professional Education and Training
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Master's Degree in Teacher Training
2023 - 2024
Master's Degree in Teacher Training for Compulsory Secondary Education, Baccalaureate, and Vocational Training at Isabel I de Castilla University.
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MicroStrategy Education
2019 - 2020
Advanced training in MySQL and MicroStrategy for business dashboard development
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Bachelor's Degree in Computer Engineering
2014 - 2019
Focused on computing, statistics and software development.
Blog
Publishing your app on Google Play Store
Publishing an app on Google Play is not just clicking “Upload” and waiting. The process has changed, and today many developers get stuck without understanding why.
Designing for Apple the Right Way: Applying HIG in React Native
The most important Apple HIG principles and how to implement them in React Native apps.
No user left behind
The most important accessibility practices you should adopt right away.
A Complete Guide Uploading your App to the Apple Store
Step-by-step instructions for registering, configuring, and submitting your app for approval.
Mastering Bottom Tab Navigation in Expo
Getting Started with Expo Router and Bottom Tabs. Expo Router brings file-based routing to React Native, making it simple to organize your screens and layouts.
Implementing Google Mobile Ads
This article aims to assist developers facing similar issues by providing a comprehensive guide. It focuses on a bare workflow approach, detailing the steps from an initial setup to a production-ready environment.
Why Fonts Matter in Web Design
Fonts do more than just display words; they shape how we perceive a website, influence readability, and even impact user experience.
Button Design
Button design best practices: well done, goes unnoticed.
Dark/Light Mode
Implementing Light and Dark Mode with Color Themes in Expo React Native
Social Share in React Native
Integrating social sharing features into an app can significantly enhance its visibility, foster user engagement, and attract new audiences organically.
From React Native Navigation to Expo Router
The transition from React Native Navigation to Expo Router marks a significant evolution in the React Native ecosystem, prioritizing simplified navigation, enhanced developer experience, and alignment with modern web development standards.
Mastering Safe Areas in Expo Router
A Comprehensive Guide to Managing Padding and Margins in React Native
Multilingual Websites Using Bootstrap
How to implement multilingual functionality in a Bootstrap-based website with a simple and efficient approach, requiring only a few steps