BACKEND · SYSTEMS IN PRODUCTION

I build backendthat holdsunder real load.

Daniel Villarreal — I design and run systems that stay stable when traffic spikes: APIs, data, and the infrastructure behind them.

eter-mx.com · in production
FEATURED PROJECTIn production

Eter — Clinical Management SaaS

full stack development alongside a partner. Designed the API contracts and validation layer with Zod under a hexagonal architecture, built the scheduling, records and billing modules, defined the design system, and set up the CI/CD pipeline with TDD on a serverless deployment.

Next.jsTypeScriptSupabasePrismaZodZustandStripeCloudflare R2
View live
In operation · Private code

Bio Pappel — Incident Management System

independent design and implementation of the complete system.

ReactViteTailwind CSS
Honorable mention · $10,000 MXN · Public repo

Durania — Livestock Management Platform

backend: data model, APIs, web interfaces and deployment infrastructure.

PythonPostgreSQLRedis
Public repo · Documented

Nexo IA — Multi-agent Omnichannel Hub

agent system architecture and full stack development.

TypeScriptNext.jsLangGraph.js
Collaboration · 2024

Hospital del Niño de Durango — Patient Administration

frontend, role-based authentication and relational database modeling.

PHPSQLLinux

About

Systems that reach production and hold under load.

Portrait of Daniel Villarreal
Durango, México

I'm Daniel Villarreal, a full stack developer in Durango, México, focused on backend, real-time and multi-tenant architectures. I've spent close to two years building systems for real users: from a ticketing system that runs inside a company to Eter, a clinical management SaaS I'm building with a partner.

I care about what happens behind the interface: data isolation between organizations with Row-Level Security, real-time telemetry, APIs with clear contracts, and testing from day one with TDD and CI/CD. I study at Universidad Tecnológica de Durango (UTD), and my interest is in backend and cloud engineering.

Stack

System layers

  1. Languages

    • JavaScript
    • TypeScript
    • Python
    • Java
    • SQL

  2. Interface

    • Next.js
    • React
    • Vite
    • Tailwind CSS
    • Zustand
    • HTML5
    • CSS3

  3. Services

    • Node.js
    • Express
    • FastAPI
    • Spring Boot
    • Prisma

  4. Data

    • PostgreSQL
    • MySQL
    • MongoDB
    • Redis
    • Supabase

  5. APIs and real time

    • REST
    • WebSockets
    • Server-Sent Events (SSE)
    • RabbitMQ
    • Zod

  6. Architecture and security

    • Microservices
    • Hexagonal architecture
    • Multi-tenant
    • Serverless
    • SOLID
    • OOP
    • JWT
    • RBAC
    • Row-Level Security (RLS)

  7. Delivery and quality

    • Linux
    • Git
    • CI/CD
    • Railway
    • Cloudflare R2
    • Jest
    • Selenium
    • TDD
    • Scrum

AI-assisted development, with generated code validated through TDD and CI/CD.

Experience

Close to two years building systems for real users

  1. – Present

    Eter

    Full Stack DeveloperOwn product

    Durango, México

    Clinical management SaaS built with a partner: appointment scheduling, clinical records and billing on a hexagonal, multi-tenant architecture with Row-Level Security.

    Used by 5 doctors

    View project: Eter

  2. –

    Bio Pappel

    Full Stack DeveloperProfessional internship

    Durango, México

    Incident ticketing system I designed and built on my own, now operating inside the company: JWT with RBAC, real-time chat and status via WebSockets, and Excel-to-SQL data migration.

    Company of ~300 employees · 10+ tickets per day

    View project: Bio Pappel

  3. –

    Hospital del Niño Durango

    Developer · Scrum team leadCollaboration

    Remote

    Patient management system for a public hospital, deployed on its Linux server, with role-based access; I led development using Scrum.

    View project: Hospital del Niño Durango

Education

Education, languages and recognitions

Degrees

  • 2026 – 2027

    Software Management and Development Engineering

    Universidad Tecnológica de Durango (UTD)

    Expected completion: August 2027

  • 2023 – 2025

    Higher University Technician (TSU) in Information Technology

    Universidad Tecnológica de Durango (UTD)

    Degree in process

    2nd place, Best Integrator Project

Languages

  • Spanish · Native
  • English · B2 (Upper Intermediate), iTEP certified

Certifications

  • MetaphorceAI Programming Bootcamp50 hours
  • AWS AcademyAWS Academy Cloud FoundationsGraduate
  • CiscoLinux Essentials
  • MongoDB UniversityMongoDB University4 certifications: CRUD, Relational to Document Modeling, Schema Design Patterns (basic and advanced)

Recognitions

  • Duran-IA Hackathon · Honorable mention and $10,000 MXN prize

Hackathon participation

  • HackMTY 2025 · Backend for "Comunidad Banorte"
  • SUMMIT 2024 / HackDGO · Backend for "Agilud"

Contact

Let's talk

If you're building something that has to hold up in production, write to me.