Spec-Driven Development
Specifications that drive the project, not improvised code.
— Backend developer with Java and Spring Boot. I work with Spec-Driven and Test-Driven Development
Available for freelance work Backend developer with Java and Spring Boot.
I work with Spec-Driven and Test-Driven Development
<developer /> · building for the web
North, for the north that saw me born. Code, for what I am passionate about.
- Experience
- 2+ yrs
- Projects
- 20+
- In production
- 3+
/ about
The 180º shift
AI won't take jobs from programmers. It will give them back the ones that truly matter.
For years, the focus of this craft was knowing languages and frameworks by heart. The arrival of AI changes that: encyclopedic knowledge loses weight, and the phases that were always underappreciated —analysis, specifications, architecture, testing, security— become the heart of development once again.
And that's exactly where my strengths lie.
Who I am
My name is Javi. I'm a software developer based in Java + Spring Boot, with experience also in PHP and Python. I'm currently pursuing a degree in Computer Engineering.
I'm passionate about AI as a development tool and I work with Spec-Driven Development — a methodology where defining specifications, documentation, and testing stop being a formality and become the driving force of the entire project. I organize every project into milestones with ratified, verifiable decisions (ODD), so the plan evolves with the project instead of becoming a dead document.
Why I work this way
My profile isn't the dev who lives in the editor churning out code. It's the dev who understands the client's problem first, who designs the solution before writing a single line, and who uses AI to execute with precision what's already well thought out.
That's the paradigm shift. And it's where I add the most value.
AI as a tool
Humans direct, AI executes. Always.
Analysis first
Understanding the client's problem before writing a single line of code.
Java + Spring Boot
Robust backend with SOLID principles and clean architecture.
Education
- CFGS — Web Development
- CFGS — Multiplatform Development
- Degree in Computer Engineering — in progress
- Postgraduate — Java Application Development with Spring
- Master's in AI Development — Big School
/ stack
The tools I work with.
Pragmatic technology choices — the right tool for the job, never tech for its own sake. Here's what I reach for daily.
01
Backend
- Java
- Spring Boot
- PHP
- Python
- REST
- PostgreSQL
02
Frontend
- HTML
- CSS
- TypeScript
- React
- Astro
- Tailwind CSS
03
Practices & DevOps
- Spec-Driven Development
- TDD
- ODD
- IA
- Docker
- GitHub Actions
- Vite
- Vitest
/ projects
Selected work.
Real projects that show how I solve problems end to end — from analysis to deployment.
foodie-pickup
Launching soonWhite-label multi-tenant SaaS for home-style food businesses with a premises: finite daily portions for pickup, oversell-proof inventory and Stripe Connect payments. Hexagonal architecture, strict TDD, GDPR-ready — production by end of year.
- TypeScript
- NestJS
- Next.js
- PostgreSQL
- Hexagonal
2026 02 / 05 ValenMetro
Available on Google PlayPublished Android app showing Metrovalencia trains using GTFS open data published by the Ministry of Transport and Sustainable Mobility. 7 releases in production.
- Kotlin
- Android
- GTFS
- Material 3
ParkManager
Parking management platform with full-stack monorepo. Express API with Prisma, React web with Zustand and shared types with Zod.
- TypeScript
- Express
- React
- Prisma
- Zod
Site Visit Registry
Construction site visit logging system for a trade union organization. Hexagonal Spring Boot backend with Firebase, Flutter mobile app with maps and geolocation.
- Java
- Spring Boot
- Flutter
- Firebase
- Hexagonal
2026 05 / 05 quotadeck
Chrome Web StoreChrome extension (MV3) that live-tracks your GLM Coding Plan usage: 5-hour and weekly token windows, MCP quota and balance in one toolbar badge.
- TypeScript
- Chrome MV3
- Service Worker
- Vitest
/ client websites
Websites I delivered to real clients
End-to-end design, development and delivery, built with Spec-Driven Development. Live, in-production sites.
2026 Amaini
Personal brand for a psychologist: blog with a CMS the client edits herself, downloadable guides and integrated email marketing.
- Astro
- Sanity CMS
- MailerLite
- Cloudflare Pages
2026 JD Soluciones Eléctricas
Corporate site for an electrical company in Valencia: services, projects, FAQ and direct contact via form and WhatsApp.
- Astro
- Tailwind CSS
- Formspree
/ services
How I can help you.
My focus is on analysis, specifications and architecture — the phases that make the difference between a project that scales and one that doesn't.
Backend & APIs
Robust REST APIs with Spring Boot, clean or hexagonal architecture and SOLID principles. Solid data modeling, testing and security by design.
01Full-Stack Development
Integrated web and mobile applications from end to end. Backend, frontend and mobile working as one coherent system.
02AI-Assisted Development
Projects driven by Spec-Driven Development. AI executes what's well-specified — analysis, documentation and testing (TDD) drive the entire process.
03Consulting & Architecture
Problem analysis, architecture reviews and solution design before writing a single line of code. Where I add the most value.
04Need something different?
Let's talk about your project / contact
Let's build something together.
Got a project in mind, or just want to explore an idea? I reply to every serious inquiry within one business day.
Currently accepting new projects