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Leonardo Caimmi

Full Stack Developer

University Technician in Programming

I build scalable solutions end to end: the interface people touch, the APIs that hold it up, and everything from the data model through to production.

01 / Profile

Who is behind the code

University Technician in Programming, graduated from Universidad Tecnológica Nacional de Mar del Plata (UTN FRMDP). I currently work as a Full Stack Developer.

At DESSA Tech I build cross-platform web and mobile applications with Expo, FastAPI and Supabase, with integrations to the ARCA API for electronic invoicing, a WhatsApp bot straight through Meta, and payment automation with Mercado Pago Checkout Pro.

Alongside that I am a Teaching Assistant at UTN, currently on Computer Architecture and Operating Systems. Across 2025 and 2026 I worked through the rest of the courses on the programme, helping students reason problems out and with whatever else they needed.

Education

English · Level 3
CEM English · Mar 2026 — Present
Spring Boot course
UTN FRMDP · Sep 2024 — Dec 2024
University Technical Degree in Programming
UTN FRMDP · Feb 2023 — Dec 2024

02 / Trajectory

Mission log

Where I have been, what I built, and what stayed running.

  1. LOG 03

    Full Stack Developer

    DESSA Tech

    Argentina · Remote

    End-to-end product work: cross-platform web and mobile applications.

    • Cross-platform development with Expo, centralising the web and mobile code so it stays maintainable over time.
    • Designed and implemented REST APIs with FastAPI, with documented contracts and JWT-based security.
    • Modelled PostgreSQL databases and implemented Row Level Security, policies and triggers in Supabase.
    • Integrated the ARCA electronic invoicing web services (WSAA and WSFE) to issue and validate fiscal receipts.
    • Integrated payments through the Mercado Pago Checkout Pro API inside the sales flow.
    • Built a WhatsApp bot on Meta’s API, as a channel of the product.
    • Built the product’s marketing site with Astro.
    • Integrated AI services into the product.
    • Python
    • FastAPI
    • TypeScript
    • Expo
    • React Native
    • Astro
    • PostgreSQL
    • Supabase
    • Row Level Security
    • Mercado Pago Checkout Pro
    • WhatsApp Business API
    • ARCA (ex AFIP)
    • OpenAI API
  2. LOG 02

    Teaching Assistant

    Universidad Tecnológica Nacional de Mar del Plata

    Mar del Plata, Argentina · On-site

    Supporting students across six courses spanning everything from pointers in C to application architecture with Spring Boot.

    • Programming III: application architecture and REST APIs with Spring Boot.
    • Programming I: fundamentals, memory and pointers in C.
    • Databases I and II: relational modelling, normalisation and SQL on MySQL.
    • Systems Methodologies II: design patterns applied to real problems.
    • Computer Architecture and Operating Systems: systems fundamentals and concurrency.
    • Java
    • Spring Boot
    • C
    • MySQL
    • SQL
    • Design Patterns
    • Data Modeling
    • UML
  3. LOG 01

    Freelance Full Stack Developer

    Freelance

    Mar del Plata, Argentina

    Custom systems built to solve a concrete problem: points of sale such as the POS, automations and accounting tools. Software used every single day that cannot fail at the counter.

    • Point-of-sale system running in production at the UTN FRMDP buffet, handling checkout, stock and receipts every day.
    • Payment integration with Mercado Pago Checkout Pro, including webhook handling and payment state reconciliation.
    • Gathered requirements directly with the client and shipped releases without interrupting day-to-day trading.
    • TypeScript
    • React
    • Tauri
    • Rust
    • Angular
    • Java
    • Spring Boot
    • PostgreSQL
    • Supabase
    • Mercado Pago Checkout Pro
    • REST APIs

03 / Missions

Systems in orbit

Three systems, all in production. Client repositories are private; the detail of the work is in the timeline.

  • DESSA Tech

    2025
    • In production
    • Private repository

    A cross-platform product on web and mobile, over in-house APIs and a PostgreSQL database governed by security policies. It integrates ARCA electronic invoicing and Mercado Pago Checkout Pro payments.

    Stack

    • Python
    • FastAPI
    • TypeScript
    • Expo
    • React Native
    • Astro
    • PostgreSQL
    • Supabase
    • Row Level Security
    • Mercado Pago Checkout Pro
    • WhatsApp Business API
    • ARCA (ex AFIP)
    • OpenAI API
  • POS

    2026
    • In production
    • Private repository

    A point of sale in daily use at the UTN FRMDP buffet: a Tauri and React desktop application at the counter, and a web dashboard that follows the day in real time.

    Stack

    • TypeScript
    • React
    • Tauri
    • Rust
    • PostgreSQL
    • Supabase
    • REST APIs
  • Cosmos Portfolio

    2026
    • In production
    • Open source

    This very site. Content lives as data validated at build time, both languages have routes of their own, and every response ships with hardened security headers.

    Stack

    • TypeScript
    • Next.js
    • React
    • Tailwind CSS
    • Vercel

04 / Constellations

Technical stack

Grouped by area, and within each one in the order they usually get reached for.

Filter by domain

Languages

What the code is actually written in. Everything else is tooling around these.

  • Java
  • TypeScript
  • Python
  • JavaScript
  • C
  • Rust

Backend

Where the business logic lives: services, contracts and the rules that hold the product together.

  • FastAPI
  • REST APIs
  • Spring Boot
  • Design Patterns
  • UML

Frontend

The surface people touch: web, mobile and desktop, from a single codebase wherever possible.

  • React
  • Expo
  • HTML
  • CSS
  • Next.js
  • Astro
  • Tauri
  • React Native
  • Angular

Databases

The schema is the first architectural decision. Relational modelling with authorisation resolved in the engine.

  • SQL
  • PostgreSQL
  • MySQL
  • SQLite
  • Data Modeling
  • Row Level Security

Tooling

Everything around the code: platforms, deployment, contract documentation and ways of working.

  • Git
  • GitHub
  • Supabase
  • Firebase
  • Vercel
  • Railway
  • Swagger
  • Postman
  • Codex
  • Claude Code
  • Docker
  • Jira
  • Kanban
  • Scrum

05 / Transmission

Open a channel

If you have a project, a role, or simply a technical question, write to me.

Send a message

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