Emilio Fonseca — Full-Stack Developer

Summary

Full-Stack Developer who builds production software end to end — web apps (ERP, e-commerce, management tools), data & BI, and applied AI. I integrate REST APIs with Python (FastAPI) and Node.js and turn manual operations into software that runs itself. Currently shipping to production, with a portfolio of live, explorable demos.

Experience

Full-Stack Developer — MN del Golfo2025 – Present

Materials retail chain · Tamaulipas, MX

Ship internal production software — web apps, dashboards and automations — used daily across the company's branches, replacing manual workflows with self-running tools.
Built AI assistants on the official WhatsApp Business API (text, voice and image) that resolve routine queries 24/7 and cut hours of repetitive manual work each week.
Integrated systems end to end with Node.js, React, SQL Server, Firebase and Docker — including the ERP (Dynamics 365 Business Central) — so data flows automatically instead of by hand.

Selected Projects

Dexter — Open-source AI agent platformApache 2.0

Python · Go (TUI) · SQLite (FTS5) · MCP · multi-LLM

Built a configurator that extends AI agents with 46+ lazy-loaded skills and persistent memory (Engram) across 6 agent platforms, backed by 99 automated tests.
Implemented a multi-LLM router with fallback across 4 providers, a WhatsApp auto-responder, computer-use GUI control and 112+ importable community flows.

GitHub ↗

Vértice — Full-stack work-management appReact · FastAPI

TypeScript · PostgreSQL · Docker · offline-first PWA

Developed an offline-first PWA to manage projects, quotes and payments end to end, with secure JWT auth and a Dockerized FastAPI + PostgreSQL backend.

Live demo ↗

Vitrina — E-commerce storefrontReact · Vite

Responsive UI · cart · search

Built a fully responsive online store with category catalog, cart with promotions, stock alerts and instant product search.

Live demo ↗

Dino AI — Reinforcement-learning game agentPython · PPO

Stable-Baselines3 · OpenCV · PyTorch

Trained a reinforcement-learning agent (PPO) that learns to play Chrome's dino game on its own from on-screen pixels via computer vision.

GitHub ↗

Technical Skills

Languages

PythonTypeScriptJavaScriptSQLC#

Frontend

ReactViteTailwindPWA / offline-first

Backend

Node.jsExpressFastAPIRESTJWTOAuth

Data & DevOps

PostgreSQLSQL ServerFirebaseDockerGitLinuxCI/CD

AI & LLMs

GPT-4oClaudeWhisperRAGPrompt engineeringTool callingMCP

Education & Certifications

B.Sc. Computer Systems Engineering

Universidad Autónoma de Tamaulipas · 2020 – 2025

Certifications

AI from Zero to Production — BIG School (2026); Data Fundamentals — Google / Coursera (2026); additional Coursera & Mastermind certificates (development, cybersecurity, game development).

Honors & Languages

ICPC Mexico Grand Prix 2022

Competitive algorithmic problem solving.

Languages

Spanish (Native) · English (B2, Intermediate-Advanced)