Freelance Data Engineers in Madrid

Freelance Data Engineers in MadridFreelance Data Engineers in Madrid

Projects People

Berckan Guerrero

pro

14+ years building fast, accessible websites. AI Friendly.

1x: Hired

5.0: Rating

7: Followers

14+ years building fast, accessible websites. AI Friendly.

Cover image for Where Are They? (dondeestan.cl):

Full-stack platform

Where Are They? (dondeestan.cl): Full-stack platform built on Supabase PostgreSQL from the ground up. Designed and implemented the complete database architecture: 63 migrations, Row Level Security (RLS) policies, full-text search with Spanish stemming, and incremental data sync using SHA-256 change detection. The project aggregates 3,216+ records from 4 external sources through a Python ETL pipeline with 99% deduplication accuracy, AI-powered image restoration (Real-ESRGAN + GFPGAN), and a Nuxt 3 frontend. Hosted on GitHub with a monorepo structure, CI/CD via GitHub Actions, and Vercel deployment. This project demonstrates deep Supabase expertise: auth, storage, database design, RLS, edge functions, and seamless integration with a modern frontend stack.

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358

Cover image for RAVEN: AI-powered knowledge management app

RAVEN: AI-powered knowledge management app with notes, tasks, and a built-in AI chat. Built with Nuxt 4, Vue 3, TypeScript, Supabase (PostgreSQL, Auth, RLS), and Gemini AI. 34 components, 25 composables, 13 database tables, 12 AI functions including streaming chat, voice input, and automatic conversation titles. Full i18n (EN/ES), offline support with sync queue, real-time CRUD, folder organization, and workspace-based content separation. Built for a private client, actively developed.

2

365

Cover image for SPEEDDOC: AI-powered web performance optimization

SPEEDDOC: AI-powered web performance optimization tool that scans websites, diagnoses bottlenecks, and generates ready-to-implement fix code. Built with Next.js 16, TypeScript, and Tailwind 4 on Vercel. Designed for developers who want actionable performance fixes instead of generic audit reports. Currently in development as part of a Vercel AI Accelerator application. Personal project.

2

434

Cover image for PartSpace: B2B SaaS marketing website

PartSpace: B2B SaaS marketing website for the manufacturing sector, built with Nuxt 4 and Storyblok. Developed 100+ reusable CMS components, integrated real-time commodity pricing via FRED API, implemented strict Content Security Policy (CSP) with enterprise-grade security headers, and delivered full English/German localization with 8 dynamic sitemap variants. Delivered during my time at Yumeda Studio.

2

549

Data Engineer(1)

Software Engineer: Building Awesome Webs Apps & Products

Software Engineer: Building Awesome Webs Apps & Products

Cover image for Lead Engineer, eth-roulette.com

Lead Engineer, eth-roulette.com

0

6

Cover image for CTO, OpenBroker.com

CTO, OpenBroker.com

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13

Cover image for CTO, Subletny.com

CTO, Subletny.com

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13

Cover image for Product Manager, Full-stack Engineer, CleanHero

Product Manager, Full-stack Engineer, CleanHero

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5

Data Engineer(1)

Spyros Mavroforos

Data Engineer | Azure & Power BI Expert Developer

Data Engineer | Azure & Power BI Expert Developer

Cover image for Power BI Analytics

Power BI Analytics

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0

Cover image for Innovative Data Warehousing Implementation

Innovative Data Warehousing Implementation

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0

Cover image for Adhoc ETL / Power BI / Azure Troubleshooting

Adhoc ETL / Power BI / Azure Troubleshooting

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0

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Data Engineer(3)

Sebastiaan Wiechers

Data Engineering & Fullstack Expert 🚀

Data Engineering & Fullstack Expert 🚀

Cover image for Development of a custom ETL solution

Development of a custom ETL solution

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6

Cover image for Retrieval Augmented Generation (RAG) LLM Chatbot

Retrieval Augmented Generation (RAG) LLM Chatbot

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11

Cover image for Development of an AI-powered product configurator

Development of an AI-powered product configurator

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8

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Data Engineer(1)

Bernadett Remenyfy-Kiser

Let's unlock data-driven decision making together!

Let's unlock data-driven decision making together!

Cover image for Building a unified datawarehouse

Building a unified datawarehouse

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5

Cover image for Data-driven marketing strategy

Data-driven marketing strategy

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7

Cover image for Mobile game launch data flow setup (android, iOS)

Mobile game launch data flow setup (android, iOS)

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4

Cover image for Building data-driven culture

Building data-driven culture

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1

Data Engineer(1)