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Malt Strategy
Guillermo Contreras GoyaGC

Guillermo Contreras Goya

ML & Systems Engineer

€490/day
Valencia, ES
3-7 years
Python
Artificial Intelligence (AI)
Machine learning
Software Development
Software Engineering

Average response time: 1 hour

About Guillermo

Ingeniero ML & Sistemas con 5+ años en plataformas de datos en producción y 3+ años diseñando sistemas con LLMs en entornos reales.
Fundador de Hyperborea Technologies. Trabajo end-to-end: arquitectura, datos, ML y despliegue. Experiencia sólida en fintech (plataformas de gestión patrimonial multi-custodio, cálculo de rentabilidades, reconciliación financiera) y en sistemas críticos de alta fiabilidad.
Especializado en:

Sistemas RAG y aplicaciones LLM en producción (LangChain, MCP)
Ingeniería de datos: pipelines ETL, series temporales, PostgreSQL/Supabase
Automatización event-driven (n8n, REST, SFTP)
Infra: Docker, Kubernetes, Azure, CI/CD

C2 en español, inglés y catalán. Disponible para proyectos remotos.
Private Equity
Digital Business Models
Software Publishing
Defense and Military

  • Spanish

    Native or bilingual

  • English

    Native or bilingual

  • Catalan

    Native or bilingual

  • French

    Conversational

Remote only
Primarily works remotely

Experience

  • Hyperborea Technologies
    Founder & Lead Software Engineer
    January 2023 - Today (3 years and 6 months)
    ▸ Sole architect and engineer of a financial operations platform for an international airline — greenfield design covering event-driven automation, multi-source data consolidation, REST + SFTP integrations, and executive reporting dashboards.
    ▸ Designed and maintains the full infrastructure stack: containerized services on Azure (Containers + Blob), PostgreSQL data layer on Supabase, CI/CD via GitHub Actions and Render.
    ▸ Built fault-tolerant n8n orchestration layer with full auditability, dead-letter handling, and scheduled + webhook-triggered pipelines.
    ▸ Performs time-series feature engineering and analytical modelling on operational and financial data to power automation logic and business decision signals.
  • Valencia Mar
    ML Automation Engineer
    July 2023 - Today (3 years)
    Valencia, Spain
    ▸ Designed and shipped a production multilingual LLM chatbot (LangChain + GPT) on Telegram — reduced client response time by 70% through systematic prompt engineering and data-driven evaluation loops.
    ▸ Built and deployed n8n automation workflows replacing manual reporting, invoicing, and client communication processes end-to-end.
    ▸ Containerized and released AI services via Docker with CI/CD pipelines; authored onboarding documentation and trained non-technical staff on AI workflows.
  • Appen / Data Annotation
    Senior AI & Coding Reviewer
    May 2023 - Today (3 years and 2 months)
    United States
    ▸ Evaluated and fine-tuned LLM outputs across coding, mathematics, and multilingual tasks (EN / ES / CA / FR) under rigorous AI safety and rubric-based QA protocols.
    ▸ Developed prompt engineering strategies that measurably improved model robustness and reduced systematic failure modes across evaluated models.
    ▸ Contributed structured error analysis to RAG and LLM application design, surfacing recurring retrieval and generation failure patterns to research teams.
Check out Guillermo's experience

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Education

  • MSc
    Univ. Colorado Boulder
    2026
    MSc
  • BSc
    Catholic Univ. Valencia
    2019
    BSc

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