Freelance full-stack & AI engineer · Barcelona · EN/ES
Software that keeps working after launch.
I design and build websites, booking and payment systems, apps and AI tools for small businesses and startups, and I keep them running after launch.
Services
A fixed price, agreed before we start. Every project begins with a free 30-minute call.
From€1,5002–3 weeks
A fast website, in one or two languages, that shows up on Google and turns visitors into calls, bookings or sign-ups. You can change the texts and photos yourself.
See details — Landing page or business websiteFrom€4,0004–8 weeks
Customers book and pay online and get a private area of their own. You run everything from one panel, and confirmations and reminders go out by email and text message on their own.
See details — Web app with bookings or paymentsFrom€3,500First version in 2 weeks
An assistant that answers your customers, a phone agent that takes calls, search across your own documents, or a tool that pulls data out of forms and PDFs. Tested on real examples before your customers use it.
See details — AI tools for your businessFixed price€6501 week
An app or website someone else built, or one made with AI, that keeps breaking? In one week I review it and give you a clear written report: what is wrong, what to fix first and what it will cost.
See details — Code audit & rescueOngoing work and maintenance from €45/hour or a monthly plan. Prices exclude VAT. Services →
How we work
30 minutes to understand what you need and tell you honestly whether I am the right person for it.
What I will build, the price and the dates, in writing within 48 hours. No surprises later.
Every week you see and try the real thing, not a status report.
I put it online, hand you every access and fix any problem for 30 days at no cost.
Products
Products of my own that I designed, built and launched, from the first idea to the last detail.
My product · 2026
Plumbers, electricians, cleaners and other home-service businesses get a website where customers book jobs online, and a phone app to run the day. In English and Spanish, ready in 48 hours, one flat monthly price.
My app · Android & iPhone · 2026
A habit tracker you use straight from your phone’s home screen: one circle per habit, tap it and today is done. For Android and iPhone, with no account and no ads.
My app · Mac, iPhone & Android · 2026
A private budgeting app. Take a photo of a receipt and it puts every item in the right category. Everything is encrypted and stays on your device: no account, no tracking.
My app · Mac · 2026
Dictation for the Mac. Hold a key, speak and let go: about a second later, clean text appears wherever you were typing, without the “ums” and with your own words spelled right.
My app · Mac · 2026
An app that makes any Mac keyboard and mouse sound like an expensive mechanical keyboard. The sounds come from real recordings, and the app tells you honestly which ones are.
The philosophy
Software is finished when it works for real people, not when the demo looks good. I check what AI produces instead of trusting it blindly, take care of the boring details, and only deliver what I would be happy to look after myself.
I'm Alejandro, a full-stack and AI engineer based in Barcelona. Full-stack means I build every part of a product: what people see and use, and the systems behind it that store the data, take the payments and send the messages.
Today I build AI phone agents that answer and make real calls for businesses. Before that I built an online shop platform used by many stores and a booking system for tourism. With me you talk to one person who builds the whole thing, explains it without jargon and stays responsible for it after launch.
Tools I use
Python, FastAPI, Django REST, Node.js, NestJS, Express, Webhooks, Stripe, Twilio
TypeScript, React 19, Next.js, Astro, Vite, Angular, SwiftUI, Jetpack Compose
LLM APIs, RAG / GraphRAG, Embeddings, LangChain, Evals, Whisper, PostgreSQL
Cloudflare, AWS, Docker, Terraform, Kubernetes, GitHub Actions, GitLab CI, Nginx, Linux
Experience
Remote teams, startups and research between Havana, Germany and Barcelona.
Jul 2026 — Present
VOICO GmbH
Germany · Remote
I design and build AI phone agents that answer and make real calls for businesses, and the platform around them.
Aug 2024 — Mar 2026
Guajiritos
Havana · Hybrid
Owned the build of an e-commerce platform where many shops each run their own online store.
Sep 2023 — Aug 2024
Guajiritos
Havana · Hybrid
A tourism platform to book accommodation, transport and tours.
Jan 2024 — Apr 2025
University of Havana
Havana
Built a system that reads documents with AI and turns them into a searchable map of facts.
Jan 2023 — Jun 2023
Cubarte
Havana · Hybrid
A platform to discover music events, artists and venues.
Education
FAQ
No. I explain every decision in plain words, you approve what matters, and you get something that works, not a pile of code.
Yes. I work remotely in English or Spanish, and my hours overlap with all of Europe and with US mornings. Calls and demos happen on Google Meet or Zoom.
You do. The code, the accounts and the domain are in your name from day one, and you get everything when the project ends.
Fixed-price projects are paid in two parts: 40% to start and 60% on delivery. Larger projects are split into stages you approve one by one.
Yes. That is what the code audit is for: in one week you know what state it is in, what to fix first and what it will cost.
Of course. Send it before the first call if you need to share details.
Problems are fixed free for 30 days. After that I can keep it running with a monthly plan, or hand it to your team with clear documentation.
Let's connect
Have an idea or a project in mind? Book a call or tell me about it here.
Tell me what you need and when. I reply within one business day, in English or Spanish.
Book a free 30-min callPick a time that suits you. No commitment.