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Juan Hernandez CastilloJH

Juan Hernandez Castillo

ERP Technical Consultant — Full Stack Developer

€550/day
Terrassa, ES
3-7 years

Average response time: 1 hour

About Juan

I am an ERP Technical Consultant and Software Developer specializing in ERP implementation, system customization, API integrations, and process automation. I help organizations optimize their business processes and extend their digital solutions through reliable and scalable technical development.

My expertise includes C#, .NET, SQL Server, backend engineering, API development, and data-driven automation. I have worked with industrial companies, public institutions, NGOs, and digital businesses — delivering integrations, custom modules, and workflow improvements that create real operational value.

I contribute to full-cycle ERP enhancement projects, translate functional requirements into solid technical solutions, and support teams with best practices in development and architecture. I also mentor junior developers and assist in improving internal standards and processes.

What I can help you with
• ERP implementation & customization
• C# / .NET development
• API integration & automation
• SQL Server & database optimization
• Backend development & system architecture
• Technical troubleshooting & performance improvements
• Code review, refactoring & developer mentoring
• Data workflows (Python, Pandas, NumPy)

I combine strong technical knowledge with clear communication and a practical, problem-solving mindset. My goal is to deliver clean, maintainable solutions that align with the real needs of your business.
  • French

    Native or bilingual

  • Spanish

    Native or bilingual

  • German

    Basic

  • Catalan

    Native or bilingual

  • English

    Native or bilingual

Can work on-site
Terrassa (up to 50km)

Experience

  • Unit4
    Technical Consultant
    January 2024 - Today (2 years and 6 months)
    • Designed and deployed customized ERP solutions for multiple organizations, including industrial companies, NGOs, and municipalities.
    • Led technical implementations ensuring alignment with business processes and user needs.
    • Mentored team members and contributed to improving internal development standards.
    • Collaborated closely with cross-functional teams and clients to deliver high- quality ERP enhancements.
    • Supported the evolution of corporate systems through automation and modular integrations.
    ERP System Customization ERP Integration with External Systems C# IT Project Management ERP
  • Doxaclick S.L.
    Software Developer
    January 2022 - January 2024 (2 years)
    • Developed and maintained large-scale platforms in Symfony.
    • Automated data extraction from over 50 APIs, integrating Google APIs and Selenium.
    • Worked with Python (NumPy, Pandas, PyTorch) for data processing and predictive analysis.
    • Managed SQL databases and optimized backend performance.
    • Designed and administered dashboards using Grafana and Tableau.
    • Developed and launched production websites including logiweather.com and logitopics.com.
  • Freelance
    Software Developer
    January 2019 - January 2022 (3 years)
    • Created frameworks and custom scripts in Lua, C#, JS, .NET, and Python for FiveM/RedM platforms.
    • Designed and managed MySQL databases for server infrastructure.
    • Implemented security measures and mitigated DDOS attacks on hosted environments.

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Education

  • Scientific-Technological Baccalaureate
    Escola Santa Maria dels Apostols
    2022
    Scientific-Technological Baccalaureate
  • Double Degree in Computer Engineering and Business Administration
    Universitat Oberta de Catalunya
    2025
    Double Degree in Computer Engineering and Business Administration

Skill set

Categories