🐿️ The squirrel behind the blog

Hi, I’m Cesar.
Also known as Aran.

Software engineer with 15+ years building scalable systems — now diving deep into AI engineering. I write this blog as Aran DataNut, a curious squirrel who explains complex tech through nut analogies.

🤖 AI Engineer ☕ Java Architect 🚀 Founder @ Nerdy Wizard 🎓 AI/ML @ UTA McCombs

Cesar “Aran” Pasillas

Chief Nut Architect

💼 LinkedIn 🐙 GitHub

THE CHARACTER

Why a squirrel?

Squirrels are the original systems engineers. They solve complex problems with elegant, reliable systems — exactly what great software does.

“Every complex system has a simpler version hiding inside it. My job is to find it — like a nut under the snow.”

🌰

Microservices = Each squirrel guards their own tree No single squirrel controls everything. Each owns their domain.

🌰

Docker = A nut in a sealed shell Same nut, any forest, always fresh. That’s containerization.

🌰

RAG = My winter stash map I don’t memorize every nut’s location. I remember which tree to check.

🐿️

Aran DataNut

Chief Nut Architect · Programming Squirrel

Aran is the narrative voice of this blog — a curious, slightly obsessive squirrel who has spent 15+ years burying and retrieving technical knowledge across Java forests, AI clearings, and cloud canopies.

Behind Aran is a real engineer who has led teams of 15, reduced production incidents by 90%, and built AI systems with RAG, LLMs, and Whisper. The squirrel just makes it more fun to explain.

RAG Pipelines Java Spring Boot LLM Orchestration Microservices Whisper AI Vector Stores Kubernetes Python ML

THE CHARACTER

15+ years climbing trees

From Java factories to AI engineering — a career built on scalable systems and real-world impact.

🤖

2023 — Present

Nerdy Wizard Dates

Founder & CTO / Tech Product Architect

Designing full product vision and backend architecture using Java, Spring Boot, and REST APIs. Building an AI-driven matchmaking system with clustering, LLM orchestration, and RAG pipelines with vector stores for personalized recommendations.

LLM Orchestration RAG Java CTO

🔬

2025 – Present

Personal R&D — AI Voice Analysis PoC

AI Engineer (Personal Project)

Built a proof-of-concept using Whisper (PyTorch) for speech-to-text and a rule-based NLP engine to detect filler words in audio/video recordings. Implemented audio preprocessing, normalization, and segmentation.

Whisper PyTorch NLP

🚢

2025 – Present

Fleet Analytics Platform

AI/ML Engineer (Freelance)

Built a platform supporting doctoral research on GPS data ingestion and fleet analytics. Developed an ML-ready route prediction pipeline with NumPy vectorization, temporal weighting, and REST endpoints for predictions and statistics.

ML Pipelines NumPy REST APIs

💳

2021 — 2023

Altimetrik

Principal Software Engineer — Payments & Risk

Reduced production incidents by 90%, saving 30 support hours per week. Managed live support for payment systems handling ~36 million transactions per month. Decreased application startup time by 40% through root cause analysis and dependency cleanup.

Java Spring Payments Fraud Systems

🛠️

2019 — 2021

EPAM Systems

Support Lead

Led a team to optimize problem-solving by migrating email-based incidents to a structured tracking system. Standardized communication templates and generated periodic reports to implement continuous improvements.

Team Lead Incident Management

🏦

2014 — 2019

Tata Consultancy Services

Java Technical Lead & Business Analyst

Developed a credit card management module in Java/Spring Boot. Redesigned a legacy microservice to RESTful standards, reducing onboarding time. Reduced rework by 85% by correcting design flaws in notification systems.

Java Microservices Business Analysis

🌲

2010 — 2013

Accenture

Java Technical Lead — Java Factory Team

Led and mentored a team of 15 Java developers across multiple projects. Eliminated ~5 weekly production incidents by migrating legacy systems from PHP to Java. Team excellence directly resulted in the company acquiring 5 new projects from the same client.

Team of 15 Java Migration Mentoring

The Toolkit

What’s in the stash

15+ years of accumulated nuts — from Java roots to AI branches.

☕

Java & Spring Boot

Spring Boot Spring Batch Microservices REST APIs Kafka

☁️

Cloud & DevOps

AWS Docker Kubernetes CI/CD GitHub

🤖

AI & Machine Learning

RAG Pipelines LLM Orchestration Whisper Vector Stores Embeddings

🤖

AI & Machine Learning

RAG Pipelines LLM Orchestration Whisper Vector Stores Embeddings

🐍

Python & Data

PyTorch NumPy ML Pipelines NLP Audio Processing

👥

Leadership

Teams of 15+ Architecture Mentoring CTO mindset Pragmatic

THE ROOTS

Education & Certifications

🎓

Post Graduate Program in AI & Machine Learning: Business Applications

UTA McCombs School of Business, Texas, US

2025 — Ongoing

📚

MSc Information Technology Management

Universidad Tecmilenio, Mexico

2019 — 2021

💻

BSc Computer Science

Instituto Tecnológico José Mario Molina Pasquel, Mexico

2002 — 2007

🏅

Oracle Java SE 7 Programmer I

Oracle Certification

2012

🧙 Beyond the blog

Founder of Nerdy Wizard

Building an AI-driven matchmaking platform with clustering, LLM orchestration, and RAG pipelines. Where the CTO mindset meets real product development.

💼 Connect on LinkedIn 🐙 See the code