Description

I'm a Senior Full-Stack Developer with 7+ years turning ideas into shipped products — from early-stage startup MVPs to internal platforms used by enterprise teams across ES and the EU.

My sweet spot: building modern B2B SaaS in Python and TypeScript, and weaving AI into features people actually use RAG pipelines over private data, LLM-powered assistants, semantic search, and the engineering glue that turns a ChatGPT prototype into a production-grade product.

What I typically work on:

- Backend & APIs: Python (Django, FastAPI, Flask), Node.js (NestJS, Express), REST & GraphQL, PostgreSQL, Redis. Clean architecture, SOLID and DDD when the project earns it.

- Frontend: React (Next.js, Server Components), Vue / Nuxt, Astro, TypeScript, Tailwind. Interfaces that feel fast and don't break.

- AI & LLMs: RAG systems, embeddings, vector databases (Pinecone, Chroma, pgvector), LangChain / LangGraph, prompt design, evaluations and cost control.

- Cloud & DevOps: AWS, Google Cloud (BigQuery, Cloud Storage, Pub/Sub), Docker, CI/CD with GitHub Actions, GitLab CI and Jenkins.

- Mobile when needed: React Native and Flutter.

I've worked with Vocento, PENTAX Medical, AEDV Spain, Indra and Sandav, building experience across banking, healthcare and media, plus a steady flow of startups sometimes as solo engineer shaping the stack from day one, sometimes as Tech Lead inside a product team.

What clients tell me I'm good at: understanding the business before writing a single line of code, shipping what's actually useful, and being the senior engineer who moves between backend, frontend and AI without dropping the ball.

Outside the terminal: continuous learner, future-teacher-someday, and a frequent traveler who finds the best ideas at 30,000 feet.

Currently available for freelance per project or monthly retainer, fully remote. Happy to plug into your product team for a sprint or a full year.

Industry field of expertise

Languages

Spanish
Native or bilingual
English
Fluent

Workplace preferences

Remote only

Primarily works remotely

Mr.Milú
Senior Full-Stack Developer
INTERNET OF THINGS (IOT)
August 2024 - Today (1 year and 10 months)
Madrid, Spain
- Build and ship full-stack features end-to-end: backend with Python (Django REST Framework) and frontend with Angular and React (TypeScript), owning APIs, data models and UI integration.

- Design data pipelines and integrations on Google Cloud — BigQuery for analytics, Cloud Storage and Pub/Sub for event-driven flows, and Cloud Data Transfers for automated ingestion — with async processing handled by Celery.

- Operate containerized services with Docker, CI/CD and automated testing (Pytest / Jest), keeping the path from feature branch to production fast and reliable.

- Bring AI into daily development and product features: integrate OpenAI and Anthropic (Claude) APIs where they add real value, work with Anthropic Skills, and use AI-assisted coding tools (Claude Code, GitHub Copilot) to ship faster without compromising quality.

- Partner with product and design to translate business needs into clean, maintainable code — SOLID principles, agile practices, and code that future-me doesn't hate.

Stack: Python · Django REST Framework · Angular · React · TypeScript · BigQuery · Google Cloud (Storage, Pub/Sub, Data Transfers) · Docker · Celery · CI/CD · SQL · Git · OpenAI API · Anthropic Claude API.
AngularJS Python Django Django Rest Framework docker-compose
OMD HR Consulting
Senior Front-end Developer
HUMAN RESOURCES
July 2023 - Today (2 years and 11 months)
Madrid, Spain
- Led the design and development of complex, scalable front-end architectures in React and TypeScript, with GraphQL integrations — owning both day-to-day delivery and long-term maintainability.

- Built and maintained a robust design system on Storybook following Atomic Design principles: reusable components, layouts and environments that kept UI consistent across products and unblocked parallel work between teams.

- Continuously refactored and optimized the front-end architecture, keeping it aligned with current web development best practices (performance, accessibility, modern React patterns).

- Worked in close collaboration with UX/UI designers and backend teams to ensure smooth integration between interfaces and APIs — clean handoffs, fewer surprises, faster iterations.

- Applied SOLID principles and clean code practices so the system stayed easy to extend as new product requirements came in.

Stack: React · TypeScript · GraphQL · Storybook · Atomic Design · JavaScript · HTML · CSS · Git.
React.js React Testing Library JavaScript Javascript / JQuery Python (Programming Language)
Vocento
Senior Full-Stack Developer
INTERNET OF THINGS (IOT)
January 2023 - July 2023 (7 months)
Madrid, Spain
- Built real-time results modules and data visualizations for Vocento's coverage of the Spanish 28M 2023 regional and local elections — a high-visibility product consumed by millions of readers on election night.

- Delivered multiple React components and interactive charts that rendered live scrutiny data: parties leading by region, province and municipality, updated continuously as results came in.

- Engineered the front-end to handle high concurrency and traffic peaks, working in tight coordination with editorial and data teams under hard deadlines.

- Shipped the full stack end-to-end using Node.js, React.js and vanilla JavaScript, with a strong focus on performance under load and correctness of the displayed data.

Stack: React.js · Node.js · JavaScript · TypeScript · Real-time data · High-traffic front-end · Git.
React.js Node.js JavaScript Typescript Javascript / JQuery

Check out Oscar Iván's experience

Alvaro

Mr.Milú

Reviewed on 31/07/2024

Gran profesional, serio y técnicamente muy potente. Capaz de hacer fullstack de verdad. Uno de sus skills era React y tuvo que tocar Angular y en muy poco tiempo se puso al nivel. Volvería y volveré a trabajar con él.

Ignacio

KOP STADIUM S.L.

Reviewed on 25/05/2024

Hemos estado encantados tanto con la comunicación y la disposición como con la calidad técnica de Oscar. Se ha comprometido con los plazos e hitos desde el primero momento y ha hecho que podamos llegar en tiempo a lo que nos habíamos propuesto. Además, ha dado feedback sobre el proyecto y el código muy útil para el futuro. Ha detallado muy bien todas las tareas y desarrollos que ha ido realizando con nuestro equipo. Volveríamos a trabajar con él sin dudarlo y lo recomendamos al 100%.

Show all 8 reviews