Armando Cesar Martin Calderón
Full-Stack AI Engineer · Claude Certified Developer (Anthropic)
Montevideo, Uruguay (UTC-3) · Remote / Hybrid
Full-stack engineer with 6+ years shipping production web products end to end: TypeScript, Next.js and NestJS on the front and back, Python services, payments, SSO and Docker. Today I'm the lead author of the base platform that Plan Ceibal's development team uses to start new web apps, and I've built full products on top of it. I work AI-native: I designed my own agent environment, with security guardrails, custom skills and subagent orchestration, so I ship faster without losing control. My focus now is AI product engineering: LLM features, agents and tool integrations that hold up in real products.
Reception
Tell me what you're looking for and I'll point you to the right room.
What are you looking for?
Platform
The base platform Plan Ceibal's team starts new web apps from.
- Lead author of the Next.js 16 project template that the team uses to start new Ceibal web apps. It ships with SSO (Google, Microsoft Entra ID, CAS), strict TypeScript, Zod, Vitest + Playwright and Docker.
- Co-author of the NestJS API template (TypeORM, MySQL, auth, pagination, notifications), which keeps every new service consistent from day one.
- Built a dynamic forms platform end to end: an admin backoffice, a NestJS API, and a public renderer that turns JSON form definitions into validated forms, usable standalone or embedded through an iframe.
- Built a customer master-data backoffice (Next.js + NestJS) and maintain legacy PHP and React apps alongside the new stack.
Sofis Solutions · Full-Stack Developer · Client: Plan Ceibal
The Store
A SaaS that let small businesses open an online store in minutes.
- Grew to ~100 active stores.
- Shipped merchant onboarding, Excel bulk import for products and stock, and freemium/premium plan gating in the Next.js 15 merchant dashboard.
- Built storefront checkout with MercadoPago for Uruguay and Brazil (including Pix), WhatsApp QR ordering, tiered delivery pricing and in-store pickup.
- Built backend endpoints in Python/FastAPI + MongoDB and extended the shared domain library (order lifecycle, soft-delete with stock reintegration, fractional units).
- Built the internal admin backoffice from scratch (domain-restricted Google auth, account and store analytics, plan management).
DataNest · Full-Stack Developer
SaaS that lets small businesses launch an online store in minutes.
The Lab
The agent environment I built to ship faster without losing control.
- Wrote my own security guardrail for coding agents: a hook that blocks dangerous shell commands and secret exfiltration before they run, backed by its own regression test suite.
- Built 13 custom agent skills that encode real team processes, from git workflows to reviewing untrusted code inside a network-less Docker sandbox.
- Orchestrate subagents with a model chosen per task and a machine-load check before any heavy job.
Trophies
Certifications and recognition.
- Claude Certified Developer – Foundations — Anthropic, 2026.
- Anthropic courses: Building with the Claude API · Model Context Protocol · Agent Skills · Claude Code in Action — 2026.
- English C1 (EF SET).
- Ranked #5 in Cuba and #6 in Uruguay by public GitHub contributions (2024–2025).
The Journey
From Havana to Montevideo, one product at a time.
- B.Eng. in Automation Engineering — Universidad Tecnológica de La Habana "José Antonio Echeverría" (CUJAE), Cuba.
- Marketplace frontend (React/Next.js) and an interactive map for an EU–Cuba cooperation program.
- Built React dApps for a DeFi ecosystem on MultiversX (Elrond): wallet integration and on-chain transactions (erdjs, Redux).
- Built React/Next.js dashboards on GraphQL APIs for client projects, including a logistics dashboard with a fleet-tracking map for a distribution company.
- Worked across the stack on content-driven projects backed by a headless GraphQL CMS.
- Moved to Montevideo in November 2024.
Experience
Freelance · Frontend Developer
Eldar Finance · Frontend Developer (Contract)
Samyca · Frontend / Full-Stack Developer
DataNest · Full-Stack Developer
SaaS that lets small businesses launch an online store in minutes.
Sofis Solutions · Full-Stack Developer · Client: Plan Ceibal
Skills
- AI
- Claude API & Agent SDK · Model Context Protocol (MCP) · Agent Skills · Claude Code · Vercel AI SDK · OpenAI / Gemini APIs
- Languages
- TypeScript · JavaScript · Python · PHP · SQL
- Frontend
- Next.js (App Router) · React 19 · Tailwind CSS · shadcn/ui · React Hook Form + Zod · SWR
- Backend & data
- NestJS · Node.js/Express · FastAPI · TypeORM · Prisma · MySQL · PostgreSQL · MongoDB · Redis
- Auth & payments
- SSO (Microsoft Entra ID, CAS, Google OAuth) · better-auth / NextAuth · MercadoPago · Stripe
- Quality & DevOps
- Vitest · Playwright · Docker · CI/CD · Vercel · Linux VPS
Spanish (native) · English (C1, EF SET)
voo Workshop
My productized web studio for local businesses.
- voo — Founder. A productized web studio for local businesses in Montevideo. I handle everything from sales to hosting. It runs on one template repository that spins up each client site, and 7 client sites are live (e-commerce, clinics, Stripe-powered yacht rentals).
Mailbox
Get in touch or take the CV with you.