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Tobías Pazos

Full-stack developer. I build production systems — legacy integrations, distributed workflows, and AI-assisted development.

Currently at Sheltr (construction-tech); freelancing since 2024 for clients across fintech, retail and real estate.

Selected Work

Four production systems, told as cases: the problem, the technical decisions, and what each one taught me.

For a credit-origination fintech · 19,627 contacts across 150+ campaigns

WhatsApp Campaign & Lead-Origination Platform

A two-service platform running multi-step WhatsApp outbound campaigns over the Meta Cloud API — sequenced follow-ups that stop the instant a prospect replies and hand off to a human agent.

  • Chose a PostgreSQL claim-lock dispatcher over a Redis/BullMQ queue — same at-most-once guarantee with far less infrastructure to operate.
  • Triple-checks every automated step right before sending, so a follow-up never lands on someone who already replied.
  • Crash recovery built into the data model (lease token + heartbeat), so two replicas never process the same work.
  • TypeScript
  • Next.js
  • React
  • Node
  • Express
  • PostgreSQL
  • Prisma
  • WhatsApp Cloud API
  • Cloudflare R2
  • Railway

Internal client system — not public

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Dal Santo — Argentina's leading bicycle distributor · ongoing client since Dec 2024

B2B Field-Sales & Order Platform

A mobile-first web app that replaced the field sales team's aging desktop tool — writing orders into a legacy factory database it isn't allowed to modify, and designed to keep taking orders even when that database goes down.

  • Durable outbox instead of writing straight to the factory DB — orders land in Postgres first, so reps keep selling even during factory-side outages.
  • Integrated into a legacy system I couldn't modify, mapping to its exact historical contract without breaking a live operation.
  • Idempotency without being able to index the legacy table (client-generated order id + UNIQUE constraint).
  • TypeScript
  • Next.js
  • React
  • PostgreSQL
  • SQL Server
  • Zod
  • Tailwind

Internal system — not public

Also built for Dal Santo:KTM e-commerceRaleighFire Bird

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Custom site + admin CMS for a Zona Norte real-estate brokerage · live

De Brasi — Real Estate Platform

A self-managed property catalog that replaced a slow, dated site and the brokerage's reliance on third-party listing portals — a public site buyers browse and an admin panel where non-technical staff load properties themselves.

  • Solved the orphaned-files problem from three sides (TTL sweep, split delete path, reconciliation script) so storage never leaks.
  • Media as a decoupled entity with an explicit state machine and direct-to-storage presigned uploads with a deferred, idempotent commit.
  • Domain modeling: 8-state property workflow, dual currency (USD/ARS), drag-and-drop ordered collections.
  • Next.js
  • React
  • TypeScript
  • PostgreSQL
  • Prisma
  • Cloudflare R2
  • sharp
  • Google Places
  • Tailwind

debrasi.com.ar

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Sheltr (construction-tech) · live

Operating Platform for a Construction & Architecture Studio

A web + WhatsApp platform that runs construction projects end to end — budgets, procurement, contractors, cashflow — with first-class ARS/USD accounting.

  • End-to-end feature work — from data model through backend to frontend — across the project-management, procurement, contractor and cashflow areas of the product.
  • Making financial reporting trustworthy in two currencies (ARS/USD), treating the exchange rate as a first-class concern.
  • One consistent source of truth across very different surfaces — desktop, WhatsApp from the field, and a client-facing financial summary.
  • Next.js
  • React
  • TypeScript
  • PostgreSQL
  • Supabase
  • Vercel AI SDK
  • Anthropic Claude
  • WhatsApp
  • Tailwind

sheltrhousing.com

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Other Work

Products and client sites — built and delivered.

Products & platforms

Skills

Backend

  • Node.js
  • TypeScript
  • Express
  • REST APIs
  • Background jobs & retries
  • Zod
  • WhatsApp Cloud API

Databases

  • PostgreSQL
  • SQL Server
  • Supabase
  • Prisma
  • Data modeling

Frontend

  • React
  • Next.js (App Router)
  • React Native
  • Tailwind CSS
  • HTML & CSS

AI-assisted development

  • Claude Code
  • Agentic workflows
  • AI-assisted development

Tools

  • Git & GitHub
  • Vercel
  • Railway
  • Cloudflare R2
  • CI/CD
  • Linux

About

I'm a developer based in Argentina, focused on backend and system integration. I like owning features end to end — from the data model to what the user sees — and I'm at my best on problems where systems have to stay reliable under real-world constraints: legacy integrations, distributed workflows, dirty data. I work remotely with teams across the Americas and Europe.

Education

  • Certified Tech Developer

    Digital House · 2023–2025 · Intensive full-stack software development program.

  • BSc in IT Management (Licenciatura en Gestión de Tecnología Informática)

    Universidad Abierta Interamericana (UAI) · In progress, 2025–2028 · Coursework includes OOP and software fundamentals (Java, C, C#).

  • English — C1

    Cambridge CAE