I study artificial intelligence and learn by building complete projects: from raw data to a model trained, evaluated without cheating and served behind an API. All of it with the code public.
Selected projects

Credit Risk Platform
End-to-end MLOps platform for credit-default scoring: reproducible training with a versioned model registry, a FastAPI inference API with input validation, PSI drift monitoring and a Prometheus and Grafana observability stack, all containerised with CI. Code at github.com/delcenjo/credit-risk-platform.
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Transformer from scratch
A GPT-style language model implemented from scratch in PyTorch: multi-head attention, causal masking and residual blocks written by hand, plus a byte-pair tokenizer and an ablation study. Code at github.com/delcenjo/transformer-from-scratch.
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Credit Risk Model
Credit-default risk model with rigorous evaluation: a leakage-free pipeline, cross-validated model comparison, calibrated probabilities, a cost-based decision threshold and per-segment error analysis. Code at github.com/delcenjo/credit-risk.
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AI Insight Assistant
An assistant that combines RAG and a SQL agent: it retrieves from a document corpus and queries a database, served with FastAPI and Streamlit and packaged in Docker. Code at github.com/delcenjo/ai-insight-assistant.
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RAG Document Assistant
A retrieval-augmented generation assistant over a document corpus: indexing, semantic retrieval and answers with source citations. Code at github.com/delcenjo/rag-document-assistant.
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LLM SQL Agent
An LLM agent that answers questions over a SQL database: it translates natural language into queries, runs them read-only and summarises the result. Code at github.com/delcenjo/llm-sql-agent.
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LLM Eval Harness
An evaluation harness that compares an LLM against baseline classifiers on a concrete task: reproducible metrics to tell when the LLM is worth it and when it is not. Code at github.com/delcenjo/llm-eval-harness.
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Text Summarizer
An abstractive text summariser with chunking for long documents: package, CLI and live demo. Code at github.com/delcenjo/text-summarizer.
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Customer Churn Prediction
End-to-end ML pipeline to predict telecom customer churn: data preparation, modelling and evaluation. Code at github.com/delcenjo/customer-churn-prediction.
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Creative technologist Building small universes with code *
From raw data to a deployed model
Machine Learning Pipelines
From raw data to a trained model: data preparation, leakage-free validation, model comparison and honest evaluation. Reproducible and tested, not a loose notebook.
See moreLLM Applications
RAG over documents, agents that query data and applications built on language models, with the evaluation needed to know whether they actually work.
See moreDeployment & MLOps
Getting the model out of the notebook: an inference API, containers, CI/CD, version registry and drift monitoring. So it does not stay a demo.
See moreMachine Learning
Deep Learning
MLOps
NLP & LLMs
RAG & embeddings
Model serving
Tabular data
Python

Every project starts from a simple idea: you do not understand a model until you train, evaluate and serve it yourself.
I am José, an artificial intelligence and machine learning student in Madrid. I learn by building projects end to end: data pipelines, ML models, LLM applications and the deployment so nothing stays in the notebook.
I try to make rigour weigh more than the demo: leakage-free validation, honest evaluation, calibrated probabilities and decisions tied to a real cost, not a pretty metric.
Right now: end-to-end projects across classic ML, RAG and agents, a suite of open-source tools published on PyPI, and contributions at Cylstat. Still learning every day.
Shall we connect?
Let's talk: feedback, collaboration or an opportunity.
You can write to me about a project, a technical question, to give me feedback, or about an internship or a first junior role. I always reply.
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