Software developer

From an idea to a digital product that works

I am a software developer with more than 15 years of experience and frontend roots. I build digital products end to end: interface, backend, database and deployment. You always talk to me.

I want to build a product See what I've built

Prefer to tell me directly? Write to me

15+ years building software
Experience in banking, retail and consulting
Own products with public code on GitHub

How I can help

What I can build for you

From the first sketch to a product in use, talking directly to me.

For founders, startups and companies

Product development

You have an idea, or a process that still lives in Excel and email. I deliver a working application, with its code and documentation.

Tell me about your project

MVP
A first version with just the essentials, to test the idea with real users.
Web applications
With user accounts, dashboards and your own data, on mobile and desktop.
Internal tools
What is done by hand or in spreadsheets today, in a tailor-made application.
Code you own
Frontend, backend, database and deployment, documented so someone else can carry on.

Experience

15+ years building software

I'm Juan Antonio Madueño, from Málaga. I started in frontend and have worked at startups, consultancies and large banking and retail companies, remotely with teams in Madrid, Barcelona, London and Amsterdam.

Over time I widened my scope: today I design and build complete products, with backend, database and deployment, without losing my care for the interface.

Outside of code I'm a creative person: music, tattoos and everything visual. That shows in how I care for interfaces and for the experience of the people who use them.

What I work with

React
Next.js
TypeScript
Angular
Node.js
PostgreSQL
Tailwind CSS
Storybook
StencilJS
Web Components
Jest
Cypress
Testing Library
CI/CD
DDD
Figma

2010Early days

2014Google Glass & TV

2016The craft

2018The team

Quality is automated

Tests, static analysis and continuous integration from day one. Whether something works shouldn't depend on anyone's memory.

Experience in demanding environments

Regulated environments, many people touching the same code and strict review processes. That is where my way of working comes from: review, tests and order.

Code others can maintain

Clear architecture and names that make sense. Someone else can pick up what I deliver without depending on me.

A tremendous professional with great problem-solving skills.

Companies and projects I've worked on

BBVA
Inditex
CaixaBank
Capgemini
ALTEN
GFT
moeve

I was embedded in their development teams, in many cases through consultancies. They are not direct clients of my current business.

Projects

What I can show you and what I can't

In banking and retail I've worked under confidentiality agreements: I can tell you what kind of work I did, but I can't show you the code. That's why I set myself a public challenge.

The challenge

12 months, 12 projects

Every month I publish a complete product: the working app, the code on GitHub and an article on how I built it.

1Rumbo
2Nous
3PokéVault
4In progress
5
6
7
8
9
10
11
12

3 of 12 published

And in companies, under confidentiality

Banking

Angular applications in a regulated environment

Clean architecture, automated tests and static analysis to the bank's standards.

Angular
TypeScript
Jest
CI/CD

International retail

A React frontend organized by domain

DDD and hexagonal architecture, reusable web components and end-to-end tests.

React
TypeScript
DDD
Cypress

Banking · Design System

A shared component library

StencilJS web components, documented in Storybook and used by several teams.

StencilJS
React
Storybook

Tell me about your project Follow the challenge

How I work

A simple process, no surprises

Five steps, the same for an MVP as for a larger product. Scope and budget are defined after I understand your project.

Understand the problem
We talk about what you want to solve, for whom and what already exists. This is also where I tell you whether I think the project suits me.
Define the scope
We agree what goes first and what can wait. With that I prepare a proposal with scope and budget.
Design the technical solution
I pick the architecture and tools so the product can be maintained and grow.
Build and validate
I work in short deliveries you can see and try. Each one goes through review and tests before it reaches you.
Deliver and evolve
I deploy, hand over code and documentation, and if you need it we keep improving the product.

I work alone. I use AI tools such as Claude Code to iterate faster, but everything goes through my own review and tests. If something doesn't suit me, I will say so.

What they say about me

People who have worked with me

Don't just take my word for it. This is what the people I've shared projects with have to say.

“If I had to sum up our professional relationship in one word, I would choose: TRUST. Creative, analytical and results-driven. He has been key in nurturing our development teams and technical architecture. As a developer, UX consultant or project manager, he has always delivered with quality and punctuality.”

“His level of commitment and proactivity helped us improve timelines in processes and deliveries. It is not easy to find project partners who share the same vision.”

“He demonstrated time and again an incredible capacity for adaptation. Ambitious, non-conformist and organised. Working in the same team or project as him always brings productive results through efficient methods.”

“A tremendous professional with great problem-solving skills. I highlight his learning ability and his capacity to adapt to whatever project is needed. A great colleague from whom I have learned a lot.”

Find me on LinkedIn →

Frequently asked questions

Before you write to me, this might already answer it

What I get asked most before we start working together.

Don't see your question? Send me your question →

From an idea to a digital product that works