Software Engineer · Book Author

Building
worlds
in two
languages.

By day I write code that quietly automates the shape of daily life.
By night I write stories that ask who's really in control of it.
Both are about building — and questioning — the world we live in.

Engineer
function createWorld() {
  const idea = imagine();
  return build(idea);
} // repeat
Writer
She typed the first line.
The cursor blinked — patient,
waiting for the world
to begin.
Selected Works

What I've built
& written

System

Sentry Agent

AI-powered email and Teams automation that replies on your behalf — non-committal, always engaged. Built with Playwright, Claude API, and a local SQLite task board.

Python · Playwright · Claude API2025
Novel · Published 2025

Ecos en la Oscuridad

A psychological thriller of technological terror, mapping the frontier between justified paranoia and mental collapse. Where does the algorithm end and the mind begin?

Amazon Kindle · hardcoverJanuary 2026
Tool

Quill

Cross-platform AI writing assistant that lives in your system tray. Hotkey-triggered overlay for rewriting, coaching, and translating any selected text using local LLMs.

Python · Tauri · Ollama · Gemma2025
Fragment

Three, One, Two

The lights flickered. Not a power cut — something more deliberate. A pattern. She counted under her breath, already knowing what came next.

Short fiction2024
Platform

EKS Deploy Pipeline

End-to-end XL Deploy configuration for multi-namespace Kubernetes deployments. Infrastructure-as-config with environment-scoped dictionaries and automated rollback.

XL Deploy · Kubernetes · AWS EKS2025
Security

IIS Hardening Guide

Production-grade security configuration for internet-facing .NET/React applications. Covers TLS, response headers, request filtering, and dynamic IP restriction.

IIS · .NET · Security2025
Philosophy

Every system I engineer is a story — with characters (users), plot (flow), and stakes (failure modes). Every novel I write is a system — with architecture, logic, and edge cases the author must resolve. The tools are different. The instinct is the same.

Mario Esquivel signature
About

Two modes.
One person.

I'm a software engineer based in Montréal who builds automation systems, devops pipelines, and AI-powered tools. I care about practical solutions that actually get used — not elegant abstractions that rot in a repo.

I'm also a novelist. My first book, Ecos en la Oscuridad, is a psychological thriller about technology, paranoia, and the quiet erosion of control. I write the way I code: architecture first, then fill in the prose.

The two identities aren't in conflict. A well-designed API and a well-structured chapter share the same DNA — clear contracts, no hidden state, predictable behavior. Both reward obsessive iteration.

// Engineering
Python .NET / C# React Kubernetes AWS Claude API Playwright IIS Ollama
~ Writing
Sci-fi thriller Narrative architecture Psychological tension Spanish · English World-building
About the author

Mario Esquivel was born among the mountains and coffee fields of Heredia, Costa Rica. A systems engineer by trade and a skeptic by nature, he has spent fifteen years writing code that quietly automates the shape of daily life. In 2021 he emigrated to Montréal, where he learned that changing languages does nothing to silence the uncomfortable questions — chiefly, how much control we have already handed to the algorithms we build.

In science fiction, he finds the precise language to explore the gap between what technology promises, and what it silently takes away.

Ecos en la Oscuridad, his first novel, is a psychological thriller of technological terror, mapping the frontier between justified paranoia and mental collapse. Published December 2025. Available worldwide on Amazon Kindle and in print from January 2026.

Mario Esquivel nació entre las montañas y el aroma a café de Heredia, Costa Rica. Ingeniero de sistemas de profesión y escéptico por naturaleza, ha pasado quince años escribiendo código que automatiza la vida. En 2021 emigró a Montréal, Canadá, donde descubrió que cambiar de idioma no silencia las preguntas incómodas sobre hasta dónde hemos cedido control a los algoritmos que creamos.

Mario encuentra en la ciencia ficción el lenguaje preciso para explorar la brecha entre lo que la tecnología promete y lo que silenciosamente nos quita.

Ecos en la Oscuridad es un thriller psicológico de terror tecnológico que explora la frontera entre paranoia justificada y colapso mental. Publicado en diciembre de 2025. Disponible en Amazon Kindle y tapa dura desde enero de 2026.

Contact

// POST
/collaborations
Every project begins
with a first sentence.

accepts: interesting problems  ·  responds: 200 OK Send me yours. I'll read every word.

./send_message.sh Begin the first line