Forward Deployed Engineer
From an unclear problem to a solution in production.

I'm Juan Tomás, a Functional Analyst / Solutions Engineer at Aeroterra and co-founder of Desarrollos Guía, a custom software studio. I take unclear client problems all the way to solutions in production.

Juan Tomás Martínez
  • Location Buenos Aires, AR
  • Role Functional Analyst · Solutions Engineer
  • Timezone GMT−3
01

About

I work where business and software meet. It usually starts with a client bringing a problem that isn't well defined yet: I scope it with the people who live it, turn it into a specification, design the solution and the data model, and then build it alongside the client's and the delivery team's engineers until it's running in production.

I'm comfortable owning open-ended, high-stakes problems with little structure around them, in business domains I didn't know beforehand - energy, government, public safety. I've been doing this at Aeroterra for a year and a half. My background is in programming, so I don't stop at the spec: I also write the code, wire up the integrations and test them.

Alongside Aeroterra, I co-founded Desarrollos Guía, a custom software studio. For our main client, AudenPass - a ticketing platform that already processes real payments - I took the backend to production by directing AI coding agents (Claude Code), with a spec, TDD and review of every change.

02

Experience

Desarrollos Guía Aug 2026 - Present Buenos Aires, AR

Co-founder · Solutions Architect & Backend Engineer

Custom software studio. Main client: AudenPass, a ticketing platform live in production with real payments.

1 · Scope and design

Gathered requirements with the client, wrote the spec with acceptance criteria and designed the backend architecture and data model (16 tables).

2 · Build it by directing AI agents

Built the backend (Node.js, TypeScript, Express, PostgreSQL, Redis) by directing AI coding agents (Claude Code with subagents) through TDD, criteria-to-test traceability in CI and review of every change: 50+ REST endpoints documented in OpenAPI and ~750 automated tests.

3 · Payments and stock

Integrated Mercado Pago payments (Orders API) with HMAC-verified webhooks, idempotency and periodic reconciliation from a background worker. Designed stock control with PostgreSQL transactions and locks so tickets can't be oversold across replicas; validated with a local k6 load test (400 concurrent users, zero oversold).

4 · Deploy and deliver

Deployed on AWS (Lightsail, SES, least-privilege IAM) with GitHub Actions: database snapshot before migrating, zero-downtime rollout and rollback. Defined an OpenAPI contract that let the frontend be built in parallel, and coordinated integration and acceptance testing with the client.

  • Solution architecture
  • Backend
  • Payments integration
  • AWS (Lightsail, SES, IAM)
  • AI-agent development
Aeroterra Apr 2025 - Present Buenos Aires, AR

Functional Analyst / Solutions Engineer

Enterprise projects for clients in energy, government and public safety. I'm the first point of contact between the client and the development teams, and every project runs through the same cycle:

Clients under NDA; scope, volumes and names are not disclosed.

1 · Scope the problem

I sit with the client to understand the problem, then gather, analyze and document the functional requirements - for example, the requirements for an emergency-management solution for a national public-safety agency, organized by module with functional specs and process documentation.

2 · Design the solution

I turn that into a viable solution: architecture, relational data model, and integration of data from heterogeneous sources (KML, PDF, field forms). I present it to the client with demos and proofs of concept.

3 · Build it through to production

I share the approved design with developers and analysts and work with them until it ships - sometimes configuring the application end to end myself. Along the way I validate REST APIs and integrations with Postman, run functional tests, and automate repetitive work with Python.

Highlight · Oil & gas client

For an oil & gas client's field-operations platform, I designed a 3-level relational data model (report → event → follow-up) and a standalone inspection module, and configured the field application end to end myself, while the development team built the separate monitoring apps on that same model. One design held two independent implementations.

  • Requirements analysis
  • Data modeling
  • Solution architecture
  • Data integration
  • Demos & proofs of concept
03

Selected work

2026 Client - Desarrollos Guía

AudenPass

Backend and infrastructure for a named-ticket sales platform: Mercado Pago checkout, QR tickets by email and door access control. Live in production with real payments. Built by directing AI agents under spec-driven TDD.

  • Node.js
  • TypeScript
  • Express
  • PostgreSQL
  • Redis
  • Drizzle
  • Docker
  • AWS (Lightsail, SES)
  • GitHub Actions
  • Mercado Pago
  • Claude Code

Private repository.

2026 Automation · AI-assisted

InvGate → Jira

A tool that extracts ITSM ticket data from PDF exports and turns it into Jira-ready user stories with acceptance criteria. Built with Claude Code.

  • JavaScript
  • PDF.js
  • Tesseract OCR
  • Jira
  • Claude Code

Private repository.

2025 Machine Learning · API

World Cup 2026 Match Predictor

A backend that forecasts every World Cup 2026 match - win/draw/loss probabilities, expected goals and the most likely scorelines - served as a REST API. The engine blends a Dixon-Coles statistical model with Elo ratings and Monte Carlo simulation.

55.9% result accuracy · backtested on 2018–2022 World Cups · 48 teams

  • Python
  • FastAPI
  • NumPy/SciPy
  • Dixon-Coles
  • Elo
  • Monte Carlo

Frontend built by a collaborator; the prediction model and API are mine.

2026 Backend · REST API

Vaquitapp

The backend for a shared household-expenses app, with its product spec and use cases documented in the repo. It includes a full auth module: registration, login, JWT refresh with token rotation, and route-protection middleware.

  • Node.js
  • TypeScript
  • Express
  • Prisma
  • PostgreSQL
  • Docker
2024 Fullstack web

The Movie Verse

A fullstack movie-discovery app: browse, search and save films to personal lists. I designed it end to end - a JWT-secured REST API over my own database, with a React frontend.

  • React
  • Express
  • Node.js
  • JWT
  • REST API
  • MVC
2024 Android app

MealMind

A native Android recipe app: search meals and browse details pulled live from an external API. Built on a clean MVVM architecture with proper state handling, following Android best practices.

  • Kotlin
  • Android
  • MVVM
  • XML
  • RecyclerView
  • REST API
2023 2D game

The Knight's Odyssey

A 2D platformer with hand-animated sprites, persistent save data, and state-machine-driven enemy and player behavior - a hands-on dive into game loops and real-time logic.

  • Godot
  • GDScript
  • State Machines
  • 2D Animation
See all repositories on GitHub
04

Stack

Frontend

  • JavaScript
  • TypeScript
  • React
  • Next.js
  • HTML & CSS

Backend

  • Node.js
  • TypeScript
  • Express
  • Prisma
  • Drizzle
  • Zod
  • PHP
  • Python
  • REST APIs

Data & Mobile

  • SQL
  • PostgreSQL
  • Redis
  • Data modeling
  • Kotlin
  • Android SDK
  • MVVM

Cloud & DevOps

  • AWS (Lightsail, SES, IAM)
  • GitHub Actions
  • Docker / Docker Compose
  • Cloudflare

Testing

  • Vitest
  • Testcontainers
  • k6

Integrations

  • Mercado Pago
  • OpenAPI

Tools

  • Git & GitHub
  • Claude & Claude Code
  • Postman
  • Docker
  • VS Code
  • Android Studio
  • Godot
05

Get in touch

Have a question, a project or a problem you'd like to talk through? Send a message and I'll get back within 24 hours.