Senior AI Engineer · León, Spain · Remote

Adrian Matias

GenAI production · ML systems · consulting delivery

LLMs / RAG / agents PyTorch / transformers FastAPI · Azure · Databricks 12 years

About

Data Scientist / ML Engineer with 12 years shipping end-to-end machine learning from problem framing to production. Deep roots in core DS — ad-tech ranking & user acquisition (Appodeal, Chartboost), fraud detection, NLP (RavenPack), recommender systems, Bayesian Bandits / RL, and large-scale experimentation on Spark / Databricks.

Current work in GenAI: LLM-as-judge product that scores software vendors, grounding raw vendor documentation into cited evidence, scoring engines. Owned the typed output contract and the correctness gate set. Approach driven by simplicity, first-principles thinking, and measurable business outcomes.

Compression — removing what is not essential — is the deepest form of truth-telling in code and in thought. — working principle

Experience

detail
Senior AI Engineer detail Cavendish Professionals → PwC Contractor · León, Remote · May 2026 – Present

Senior engineer on an LLM-as-judge product that scores software vendors. Built the human ground-truth lane alone — domain-expert template parser, vendor matching, band placement, tier-weighted averaging and roll-up — the lane that reconciles human evaluator scores against model scores and makes the judge's accuracy checkable against ground truth.

Key achievements
  • Contributed to every component of the product architecture in a team of three senior AI engineers, a PM and the associate product owner.
  • Introduced and owned schema-driven, domain-driven and spec-driven development: business requirements kept as a contract artifact that agentic development builds against.
  • Owned the typed output contract and the correctness gate set — type baselines per file and rule, a complexity ratchet, mutation tests, required status checks — and designed and managed the end-to-end validation workflows behind them.
  • Created and owned full epics end to end, from business requirement to shipped increment.
  • Ran agentic development at production scale as a measured practice: cost and turn discipline tuned per model tier.
Data Scientist → DS Technical Lead detail Appodeal · León, Remote · Dec 2024 – Jan 2026

Install prediction for mobile user acquisition: cold-start, transformers, user embeddings, transfer learning, MLOps, production pipelines, parity resolution, experimentation, monitoring. Progressed toward technical leadership on ownership and strategic perspective.

Key achievements
  • Unified modeling across targets, advertisers, and platforms via attention/transformer architecture, increasing end KPI.
  • Design and deploy cold start for advertiser onboarding in two angles: transfer learning through an affinity tower trained on wider set of interactions and cold advertiser masking validated on held-out cold entities. New advertisers bid from day one from a unified model, with eCPI better than curated whitelists for inventory and demand segments. Custom PyTorch
  • Resolved parity mismatches and calibration gaps: traced discrepancies in internal transformations until models received identical inputs offline and online and their outputs matched through a complex inference server; productionized parity workflows with unit tests in Databricks.
  • Designed and proposed the user embedding system built from users' interactions with apps; realized with transfer learning at performance parity and orders-of-magnitude cost savings.
Senior Data Scientist detail Quant AI Lab · León, Remote · Jul 2024 – Dec 2024

End-to-end ML for international clients: scope review, stakeholder alignment, model productivization.

Key contributions
  • Led rapid turnaround of underperforming client ML system (utility fraud detection & ranking): surgical plan, restored accuracy/efficiency, recovered client satisfaction.
  • Surfaced critical issues in data ingestion and feature-engineering pipelines.
  • Real-time credit card fraud classifier (classical ML + deep VAE). Open: github.com/adrianmatias/ml-sandbox/tree/master/tx_class
Senior Data Scientist detail Chartboost · León, Remote · Jun 2023 – Jun 2024

Ad ranking and reinforcement learning for in-app game advertising; DSP performance via large-scale experimentation.

Key achievements
  • Bayesian Bandit RL system with policy evaluation tools; tailored online/offline evaluation frameworks.
  • Two-Towers neural ranking from recommender-systems patterns.
  • Post-mortems on adversarial DSP dynamics and model feedback loops.
Machine Learning Engineer detail RavenPack · León, Remote · Mar 2022 – Jan 2023

Text analytics, NLU, and semantic search on massive financial news data; MLOps and reproducibility.

Key achievements
  • Few-shot search personalization: simplified architecture, −30% error.
  • Active learning PoC for learn-to-rank: projected +300% annotation efficiency.
  • Long-text fingerprinting for duplicate content detection.
Earlier roles & freelance detail 2015 – 2025 · ML, fraud, teaching, consulting
Numbrs · Machine Learning EngineerAug 2020 – Oct 2021Deep Learning / Active Learning for transactions; GDPR-compliant multi-country pipelines.
IEBS School · TeacherOct 2019 – Oct 2021Webinars and masterclasses on Big Data, AI, ML.
Stratio BD · Data ScientistAug 2019 – Aug 2020Propensity/churn on Spark; BERT+graph email segmentation.
DOCOMO DIGITAL · Data ScientistApr 2017 – Aug 2019Fraud detection (99.8% specificity, <50 ms); mentored juniors.
Digilant · Machine Learning EngineerJun 2015 – Apr 2017Consumer Persona ML redesign; Game Theory attribution.
Freelance · Freelance Data Scientist / ML EngineerMar 2022 – Jun 2025Semantic search, time series, portfolio optimization.

Selected Projects

opo — AI-compiled exam preparation opo.taoaieng.io

Live paid product for Spanish public-sector exams: official law and past papers compiled once into a cited corpus of 28 topic pages and 660 tagged official items, then a 40-item diagnostic allocates the student's hours by official weight × mastery deficit. Six proven CI gates block release; no claim ships without a citation.

GenAIKnowledge compilationEvaluationPython
The Mirror github.com/adrianmatias/the-mirror

Knowledge repository based on llm-wiki for a personalized assistant and insight layer for agentic AI. Persistent synthesis across sessions.

RAGLLM wikiAgentsObsidian
RAG Blog System ml-sandbox/ragblog

Retrieval-augmented generation pipeline integrating LLMs, vector embeddings, and web crawling. Local-first path on consumer GPUs.

RAGEmbeddingsLocal AIPython
Credit Card Fraud Classifier ml-sandbox/tx_class

Real-time fraud detection API: classical classification + unsupervised anomaly signals. Deploy-ready FastAPI, Docker, RayServe.

FastAPIDockerAnomalyRayServe
The Real MLE Challenge production ML refactor

Dev-to-production refactor: inference pipelines, price-prediction API, Docker. Clean structure, reproducibility, MLOps habits.

MLOpsFastAPIDockerPyTorch
Document Classification seedtag-doc-classification

NLP classification with attention and transformer transfer learning. Batched prediction and GPU/CPU deployment paths.

NLPTransformersTransfer learning
not the tao — Podcast YouTube

Episodes on simplicity, consciousness, reality, machine learning, coding, and sovereign AI. No guests, no ads, no filler.

PodcastMLPhilosophy

Skills

Core technologies

Python, FastAPI, Pydantic, PostgreSQL, PyTorch, Transformers, Azure OpenAI / Azure / AKS, AWS/S3, Databricks, PySpark, Pandas, SQL, Docker, MLflow, Git, GitHub Actions, AI-augmented tools (Ollama, llama.cpp, Hermes Agent)

Machine learning & GenAI

LLMs, RAG, agentic systems, LangChain / LangGraph-style orchestration, document extraction & provenance, scoring engines, deep learning (attention, embeddings, transfer learning), recommender systems, NLP, RL / Bayesian bandits, MLOps, few-shot / active learning, ranking

Engineering practices

Clean code, typed contracts as source of truth, CI drift gates, OOP & FP, TDD / local e2e harnesses, reproducible pipelines, Agile / XP, production ownership

Consulting & soft skills

Multi-client consulting delivery, stakeholder communication, correctness gatekeeping, mentoring, business impact focus, simplification / unification

Education & courses

Master's in Geological EngineeringUniversity of Oviedo · 2010–2012
Degree in Mining & Energy EngineeringUniversity of León · 2012
Bachelor in Mining EngineeringUniversity of León · 2003–2007
Selected coursesCoursera / MITxClaude Code (2026) · MLOps Specialization · Deep Learning Specialization · Spark for Scalable ML · FP in Scala · Analytics Edge (MITx)

Contact

Open to Senior AI Engineer / AI Consultant roles — GenAI production, multi-client delivery, internal labs. Remote from León, Spain.