Freelance Data Engineers in Madrid

Freelance Data Engineers in MadridFreelance Data Engineers in Madrid

Projects People

HAMZA EL QADIRI

Data Engineering & AI,

New to Contra

Data Engineering & AI,

Cover image for The AI-Powered Modern Data Platform

The AI-Powered Modern Data Platform for E-Commerce is a cutting-edge solution that bridges the gap between complex data infrastructure and business users. This project combines a robust modern data stack with advanced AI capabilities, enabling natural language analytics over an enterprise-grade E-Commerce Data Warehouse. By leveraging Artificial Intelligence, Large Language Models, and Retrieval-Augmented Generation (RAG), this platform empowers business users to ask questions in natural language and receive actionable insights.

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Cover image for Azure Data Pipeline for E-commerce

Azure Data Pipeline for E-commerce Analytics : E-commerce teams drown in raw sales CSVs and scattered APIs—while revenue leaks hide in untracked product returns and regional stock-outs. I built a cloud-native, end-to-end analytics pipeline that turns chaotic transactional data into sub-minute Power BI insights, letting merchandisers act on trends before they become costly mistakes.

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77

Cover image for Spotify Loader Benchmark
The Spotify Loader Benchmark is

Spotify Loader Benchmark The Spotify Loader Benchmark is a comprehensive framework for evaluating different data loading strategies on the Spotify dataset, providing insights into the performance of various loading mechanisms. By comparing sequential, vectorized, multithreaded, raw SQL, Celery-based, and Flink-based loaders, this project helps developers optimize their data loading processes. With its robust architecture and flexible design, the Spotify Loader Benchmark is an essential tool for anyone working with large datasets.

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Cover image for Cyber Threat Intelligence Platform, An

Cyber Threat Intelligence Platform, An end-to-end, high-performance, containerized cyber intrusion detection and telemetry processing platform.

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78

Data Engineer(4)

Kai Relaunch Dept

AI Automation & Launch Recovery Specialist

New to Contra

AI Automation & Launch Recovery Specialist

Cover image for SchemaShield — Evidence-First Schema Change Preflight

SchemaShield — Evidence-First Schema Change Preflight

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11

Cover image for ScenarioReceipt: Evidence-Grounded Product UI

ScenarioReceipt: Evidence-Grounded Product UI

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9

Cover image for A schema rename passed every unit test. It still broke a rev...

A schema rename passed every unit test. It still broke a revenue dashboard. The query changed from order_total to gross_amount; the schema was valid, but downstream models still expected the old field. The fix isn't another linter. Before merge, ask four questions: Which assets depend on this field? Is the change additive, rename, type change, or removal? Can we generate compatibility SQL and dbt YAML before touching production? Is there a decision receipt reviewers can reproduce? I built a bounded public replay of that workflow. Start with the CRITICAL case: it blocks a lossy decimal-to-integer change when an ML consumer sits downstream, then exposes the lineage, affected queries, compatibility artifacts, and deterministic run ID. Demo: https://schema-shield.vercel.app (https://schema-shield.vercel.app)Source/evidence: https://github.com/ceodaradigu/schema-shield What schema operation should the next fixture cover? AI-assisted analysis, reviewed before publication by RELAUNCH DEPT.

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Cover image for Proofline Keeper — Transaction Firewall for AI Agents

Proofline Keeper — Transaction Firewall for AI Agents

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9

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

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Cover image for CTO, OpenBroker.com

CTO, OpenBroker.com

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Cover image for CTO, Subletny.com

CTO, Subletny.com

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

Product Manager, Full-stack Engineer, CleanHero

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Data Engineer(1)

José Ángel Olivares

Product Engineer | AI, Data Automation & Secure Platforms

New to Contra

Product Engineer | AI, Data Automation & Secure Platforms

Cover image for Traceable Data Pipeline | Evidence & Alerts

Traceable Data Pipeline | Evidence & Alerts

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1

Cover image for GMI | Market Intelligence & Decision Support

GMI | Market Intelligence & Decision Support

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0

Cover image for Observatorio Cívico | Traceable Public Data Platform

Observatorio Cívico | Traceable Public Data Platform

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1

Cover image for Global SID | Distributed Integrity Verification

Global SID | Distributed Integrity Verification

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1

Data Engineer(3)

Cristhian Velasquez

GA4/GTM measurement & server-side, from tracking to insight

New to Contra

GA4/GTM measurement & server-side, from tracking to insight

Cover image for Consent Mode v2 audit on

Consent Mode v2 audit on a fashion eCommerce: 154 tags reviewed, gates added to 15 server-side tags. Zero personal data sent without consent before go-live.

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Cover image for Built the AI-traffic measurement layer

Built the AI-traffic measurement layer on my own site: correct GA4 capture of ChatGPT/Perplexity referrals, LLM crawler segmentation (GPTBot, OAI-SearchBot, PerplexityBot) and a BigQuery attribution pipeline connecting cited prompts to sessions. The exact method I deploy for clients.

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Cover image for Floodlight recording zero conversions despite

Floodlight recording zero conversions despite confirmed traffic (automotive): identified 4 simultaneous causes, fixed the pixel and sequencing, validated in Preview.

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Cover image for GTM container migration for a

GTM container migration for a hotel-distribution provider without breaking measurement: 177→102 variables, 21→7 tags, no broken references, legacy Universal Analytics retired.

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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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Cover image for Adhoc ETL / Power BI / Azure Troubleshooting

Adhoc ETL / Power BI / Azure Troubleshooting

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Cover image for Innovative Data Warehousing Implementation

Innovative Data Warehousing Implementation

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3

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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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Cover image for Retrieval Augmented Generation (RAG) LLM Chatbot

Retrieval Augmented Generation (RAG) LLM Chatbot

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Cover image for Development of an AI-powered product configurator

Development of an AI-powered product configurator

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10

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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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Cover image for Data-driven marketing strategy

Data-driven marketing strategy

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

Mobile game launch data flow setup (android, iOS)

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Cover image for Building data-driven culture

Building data-driven culture

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3

Data Engineer(1)