I am a seasoned software engineer specializing in Machine Learning and AI, with extensive experience in developing backend services, AI agents, and scalable SaaS platforms. Over the years, I've contributed to various tech startups and enterprises, leading projects that range from AI-powered customer support agents to educational SaaS tools tailored for Spanish students. My passion lies in creating innovative software solutions that integrate machine learning models with reliable, efficient backend systems. I excel at designing evaluation frameworks for AI applications and have a strong background in cloud infrastructure, data pipelines, and full-stack development. I'm always eager to push the boundaries of AI technologies and deliver tangible value to users through software.

Darío López Padial

I am a seasoned software engineer specializing in Machine Learning and AI, with extensive experience in developing backend services, AI agents, and scalable SaaS platforms. Over the years, I've contributed to various tech startups and enterprises, leading projects that range from AI-powered customer support agents to educational SaaS tools tailored for Spanish students. My passion lies in creating innovative software solutions that integrate machine learning models with reliable, efficient backend systems. I excel at designing evaluation frameworks for AI applications and have a strong background in cloud infrastructure, data pipelines, and full-stack development. I'm always eager to push the boundaries of AI technologies and deliver tangible value to users through software.

Available to hire

I am a seasoned software engineer specializing in Machine Learning and AI, with extensive experience in developing backend services, AI agents, and scalable SaaS platforms. Over the years, I’ve contributed to various tech startups and enterprises, leading projects that range from AI-powered customer support agents to educational SaaS tools tailored for Spanish students.

My passion lies in creating innovative software solutions that integrate machine learning models with reliable, efficient backend systems. I excel at designing evaluation frameworks for AI applications and have a strong background in cloud infrastructure, data pipelines, and full-stack development. I’m always eager to push the boundaries of AI technologies and deliver tangible value to users through software.

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Experience Level

Expert
Expert
Expert
Expert
Expert
Intermediate
Intermediate
Intermediate
Intermediate
Intermediate
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Language

Spanish; Castilian
Fluent
English
Advanced

Work Experience

Senior Software Engineer (AI) at Zena
September 1, 2024 - Present
Designed and implemented a framework to manage AI agents including prompts, tools, guardrails, and workflows. Deployed two production-ready customer support agents (web-based and SMS). Built an evaluation framework for agent performance using LLM-as-a-Judge methodology. Developed monitoring and logging systems to track agent behavior and reliability.
Founder at Side Project
July 1, 2025 - Present
Built and launched a SaaS platform for Spanish students preparing for civil service exams. Implemented subscription payments with Stripe and deployed scalable serverless architecture with Vercel and Supabase. Designed and developed interactive learning tools including flashcards, practice tests, and past official exam papers. Achieved early traction with €200 MRR from paying subscribers.
Co-Founder at Justicio
August 31, 2024 - September 3, 2025
Implemented the RAG pattern. Deployed the embedding database and FastAPI server. Created synthetic datasets for fine-tuning and evaluation. Built a custom evaluation framework for Justicio. Fine-tuned the embedding model (Spanish language and legal context). Monitored scheduled daily ETL jobs.
Senior Machine Learning Engineer at Affirm
April 30, 2024 - September 3, 2025
Architected, designed, and developed back-end microservices, REST APIs, ETLs for data, and scheduled jobs for machine learning applications using Python. Worked on challenging problems related to credit issuance and settlement, fraud detection, ML model serving, feature stores, data quality, data drift, and model performance observability.
Machine Learning Engineer at OpenSistemas
March 1, 2021 - September 3, 2025
Developed the in-house framework to orchestrate pre-processing and training pipelines for machine learning models at Orange. Used Pandas, Numpy, Scikit-learn, Plotly, and AWS tools.
Software Engineer (Freelance)
August 31, 2020 - September 3, 2025
Developed web application backends using Django and Django REST Framework. Built financial time-series analysis tools using Python data science stack. Served clients including a large quantitative hedge fund, Feature Labs, University of Granada, Cervezas Alhambra, Universidad Complutense de Madrid, and others.
Co-Founder & Freelance Software Engineer at Co-operative Lecrin Technologies
November 30, 2018 - September 3, 2025
Developed mobile and web applications using Django and Ionic Framework. Solved various machine learning problems such as financial time series prediction and network outlier/malware detection.
Software Engineer at Department 'Experimental Psychology', Research Group 'Memory and Language', University of Granada
August 31, 2016 - September 3, 2025
Designed, implemented, and maintained a web video game platform for cognitive skills training, evaluation, and diagnosis. Developed simple psychology experiments using E-Prime and Psychopy.
Software Engineer Web at IActive
June 30, 2014 - September 3, 2025
Designed and implemented web applications using Django and jQuery.
Software Engineer Internship at Fundación I+D del Software Libre
February 28, 2012 - September 3, 2025
Designed and implemented web applications using Django and jQuery.
Senior Software Engineer (AI) at Zena
September 1, 2024 - Present
Designed and implemented a framework to manage AI agents including prompts, tools, guardrails, and workflows. Deployed two production-ready customer support agents (web-based and SMS). Built an evaluation framework for agent performance using LLM-as-a-Judge methodology. Developed monitoring and logging systems to track agent behavior and reliability.
Founder at Side Project
July 1, 2025 - Present
Built and launched a SaaS platform for Spanish students preparing for civil service exams. Implemented subscription payments with Stripe and deployed a scalable serverless architecture with Vercel and Supabase. Designed and developed interactive learning tools, including flashcards, practice tests, and official exam papers. Achieved early traction with €200 MRR from paying subscribers.
Co-Founder at Justicio
August 31, 2024 - September 3, 2025
Implemented the RAG pattern. Deployed the embedding database and FastAPI server. Created synthetic datasets for fine-tuning and evaluation. Built a custom evaluation framework. Fine-tuned embedding model for Spanish language and legal context. Monitored scheduled daily ETL jobs.
Senior Machine Learning Engineer at Affirm
April 30, 2024 - September 3, 2025
Architected, designed, and developed backend microservices, REST APIs, ETLs, and scheduled jobs for Machine Learning applications. Tackled challenging problems related to credit issuance and settlement, fraud detection, ML model serving, feature store, data quality, data drift, and model performance observability.
Machine Learning Engineer at OpenSistemas
March 31, 2021 - September 3, 2025
Developed an in-house framework to orchestrate preprocessing and training pipelines for Machine Learning models at Orange.
Software Engineer at Freelance
August 31, 2020 - September 3, 2025
Developed web applications backend using Django and Django REST Framework and developed time-series financial tools using Python Data Science stack for clients including quantitative hedge funds and universities.
Co-Founder & Freelance at Co-operative Lecrin Technologies
November 30, 2018 - September 3, 2025
Developed mobile and web applications using Django and Ionic Framework. Solved Machine Learning problems such as predicting financial time series and network outlier/malware detection.
Software Engineer at Department Experimental Psychology, Research Group Memory and Language, University of Granada
August 31, 2016 - September 3, 2025
Designed, implemented, and maintained a web video game platform for training, evaluation, and diagnosis of cognitive skills. Developed simple psychology experiments using E-Prime and Psychopy.
Software Engineer Web at IActive
June 30, 2014 - September 3, 2025
Designed and implemented web applications with Django and jQuery.
Software Engineer Internship at Fundación I+D del Software Libre
February 29, 2012 - September 3, 2025
Designed and implemented web applications with Django and jQuery.

Education

8-weeks AI program at Pi School, Rome, Italy
October 1, 2018 - December 1, 2018
Post-graduate degree in Software Engineering at ETSIIT, Universidad de Granada, Granada, Spain
January 1, 2011 - December 31, 2014
Bachelor's degree in Software Engineering at ETSIIT, Universidad de Granada, Granada, Spain
January 1, 2008 - December 31, 2011
AI program at Pi School, Rome, Italy
October 1, 2018 - December 31, 2018
Post-graduate degree in Software Engineering at ETSIIT, Universidad de Granada, Granada, Spain
January 1, 2011 - December 31, 2014
Degree in Software Engineering at ETSIIT, Universidad de Granada, Granada, Spain
January 1, 2008 - December 31, 2011

Qualifications

Deep Learning Specialization (deeplearning.ai)
November 1, 2017 - September 3, 2025
Machine Learning for Trading (Georgia Tech, Udacity)
December 1, 2016 - September 3, 2025
Deep Learning (Google, Udacity)
December 1, 2016 - September 3, 2025
PythonHack Winner, PyConES (Kernel Analytics)
September 1, 2017 - September 3, 2025
MOOC ‘Un enfoque práctico en la era del Big Data’, ETSIIT, University of Granada
July 1, 2016 - September 3, 2025
MOOC ‘Deep Learning Specialization’, deeplearning.ai
November 1, 2017 - September 3, 2025
MOOC ‘Machine Learning for Trading’, Georgia Tech (UDACITY)
December 1, 2016 - September 3, 2025
MOOC ‘Deep Learning’, Google (UDACITY)
December 1, 2016 - September 3, 2025
PythonHack 2017 Winner, PyConES (Kernel Analytics)
September 1, 2017 - September 3, 2025
30 hours course 'Un enfoque práctico en la era del Big Data', ETSIIT, University of Granada
July 1, 2016 - September 3, 2025

Industry Experience

Software & Internet, Financial Services, Education, Professional Services

Experience Level

Expert
Expert
Expert
Expert
Expert
Intermediate
Intermediate
Intermediate
Intermediate
Intermediate
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