Don't read my portfolio.
Play it.

I'm a software engineer from Buenos Aires. Six years building production platforms at Mercado Libre, Conekta, Spin and Kleva: Node.js, TypeScript, multi-tenant PostgreSQL, AWS. On my own time I design, build and run complete products, and five of them are below, real and working. Touch them.

In a hurry? or download it as a PDF.

Sebastián Elustondo

Senior software engineer · tech lead · Buenos Aires, remote (GMT-3)

sebastianelustondo@gmail.com · LinkedIn · PDF

Six years building and operating production web platforms. Node.js and TypeScript services, multi-tenant PostgreSQL with row-level security, serverless and event-driven AWS, payments and third-party integrations, and the whole delivery loop: API contracts, testing, CI/CD, monitoring, rollbacks. English B2+, professional working proficiency.

Experience

Jun 2026 – present

Kleva · Senior Software Engineer, then Tech Lead · Argentina
Lead the design and delivery of multi-tenant services with PostgreSQL row-level security; build serverless, event-driven AWS components (Lambda, SQS, CloudWatch, VPC); own OAuth and webhook integrations and API contracts; drive production readiness through automated testing, CI/CD, monitoring, alerting and rollback practices; mentor engineers.
May 2025 – Jun 2026

Mercado Libre · Software Engineer · Buenos Aires
Production Node.js and TypeScript services for high-traffic platforms; PostgreSQL schema design and migrations; a strong testing culture with Jest unit, integration and end-to-end tests; CI/CD and platform reliability.
Sep 2024 – May 2025

Spin · Full-Stack Developer · Mexico City
Full-stack services with Node.js, TypeScript and React; multi-tenant PostgreSQL with row-level security; OAuth and webhook integrations; AWS (API Gateway, S3, RDS, IAM, EC2, ECS, Secrets Manager).
Jan 2022 – Sep 2024

Conekta · Full-Stack Developer · Mexico City
Fintech and payment workflows, including checkout integrations through a proprietary payment gateway; multi-tenant PostgreSQL data models and migrations with row-level security; vendor integrations with secure API contracts; AWS, automated testing, CI/CD and production operations.
2020 – 2021

Siemens · Systems IT intern · Buenos Aires

Stack

Node.js · TypeScript · Go · PostgreSQL (schema design, migrations, RLS, multi-tenant) · Redis · AWS (Lambda, API Gateway, SQS, S3, RDS, ECS, CloudWatch, IAM, Secrets Manager) · Cloudflare Workers · Supabase · React · Next.js · Jest · GitHub Actions · Grafana · Datadog

Education and languages

Superior Technician in Systems, AHK Argentina (2020–2021) · IT Technician, Instituto Politécnico Modelo (2014–2019) · Spanish native · English B2+ · German elementary

Products I built and operate myself

pulso monitor 01

esperando señal

tap · click · space when the blip crosses the red arc · every 5th arc is golden and worth 3

Dibujá:

80s

dibujá acá — el reloj arranca con tu primer trazo

TrazoLoco

This canvas is a rebuild of the real one for this page. In the game, up to ten people share it in a room over WebSockets, no signup. Public matchmaking or a private 4-letter code; a "broken telephone" mode; chaos modifiers that force one continuous line or drawing blind; the best rounds export as vertical video.

One Node + Socket.io server runs the whole state machine: turns, scoring, letter hints, profanity filtering, and a 90-second reconnect grace so a backgrounded phone rejoins its game.
Strokes travel as normalized coordinates, so a drawing looks identical on any screen — resize this page and watch yours survive.
A 1,252-word Spanish dictionary, a Discord bot that opens private rooms, and an end-to-end smoke test that plays a full two-player game over real sockets.

play with friends at trazoloco.quovra.com

One platform, switched on per client. This is the owner panel of a real kind of customer — a barbershop — and the public site their visitors see. Flip a module. The site changes in front of you.

Barbería Hestia

Owner panel · modules

Reporte mensual enviadoowner-only · nothing changes on the public site

sitioPages, hours, map and WhatsApp. The base everything else plugs into.
turnosOnline booking with time slots and a Mercado Pago deposit.
tiendaA small catalog with real stock, sold straight from the site.
reseñasAsks happy clients for a Google review after their visit.
eventosAnnounces the next event and takes sign-ups.
avisosA newsletter box. One email a month to the client list.
reportesA monthly report to the owner's inbox. Invisible to visitors.
sociosMemberships, plans and classes, with a free trial class.

Onboarding: 0 lines of code written. 1 module live.

Barbería Hestia Villa Crespo · desde 2014

Cortes con turno,
sin espera.

Lun a Sáb · 10 a 20 h
Av. Corrientes 5120

Escribinos por WhatsAppCómo llegar

Reservar turno

Hoy 16:30Hoy 18:00Mañ 11:00Mañ 15:30

Seña por Mercado Pago · $3.000 · se descuenta del corte

Reservar y pagar seña

Tienda

Pomada mate 100 g7 en stock$9.800

Aceite para barbaÚltimas 2$7.200

Agregar al carrito

Planes y clases

Plan mensual4 cortes · barba incluida$28.000

Curso de barberíasábados · 8 clases$45.000

Clase de prueba gratis

Próximo evento: Noche de barbas

Jue 18 · 20 h · cupos limitados · trae a un amigo

Anotarme

¿Cómo te fue?

Dejanos tu reseña en Google

Novedades por mail

tu@mail.comSuscribirme

Un mail al mes. Sin spam.

Sitio sin publicar

Activá «sitio» en el panel y esta página aparece.

Quovra.

My studio, and the multi-tenant platform behind it. What you just did is the whole business model: every capability is built once and switched on per client by configuration. Bookings with Mercado Pago deposits, an online store with real stock control, review funnels, gym memberships, a site builder. The acid test for every feature: can a whole client be onboarded without writing code?

One Postgres database behind independent Cloudflare Workers, Astro SSR for the owner and member panels, R2 for uploads, Supabase Vault for per-tenant secrets.
Free-tier ceilings drove the architecture: with 5 cron triggers per account, expiring holds are computed at read time, so work scales with usage, not with tenants.
Deposits go straight to each business's own Mercado Pago account. Per-tenant credentials live in Supabase Vault; only the payment webhook can confirm, or undo, a paid booking.
Deny-all row-level security: no table is readable by any client key; every query runs server-side through the service role, scoped by tenant.

quovra.com · founding client migrated from a legacy system

Pipeline · septiembre · 3 cuentas · USD 270/mes

Cobranzas: 0 al día

Drag a lead across the board to Cobrado — or focus a card and press → / ←.

Lead 0

Barbería Hestia

sitio web

USD 120/messeguimiento: mañana
Café Ramos

menú QR

USD 60/messeguimiento: ayer

Contactado 0

Box Norte

turnos

USD 90/messeguimiento: vie 5

Cerrado 0

Cobrado 0

Reachr.

From lead to client, from client to payment. A WhatsApp-first CRM for freelancers and micro-agencies in Latin America who sell recurring services to local businesses. The part every CRM forgets is collections, and that's the part you just used. I run my own client outreach on it every day.

Debt is derived, not stored: due status is computed at read time from billing day + payments. A whole billing subsystem with zero scheduled infrastructure.
The public demo-booking endpoint is defended in layers: honeypot, anti-flood caps, an atomic Postgres rate limiter, and a DB-level UNIQUE that turns the race condition into a clean 409.
Email replies are detected without Gmail OAuth: a Cloudflare Email Worker matches the sender to a lead and advances the pipeline on its own.

Next.js · React · Supabase with row-level security · Paddle billing · Cloudflare Email Workers · Spanish and English.

reachr.quovra.com

Monthly budget · freelance, Argentina

¿Cuánto cobro?

Your rate in dollars, your month in pesos. Move anything.

You'd bill, per month

ARS0

Your hour, in pesos: ARS 0
Hours billed per month: 0 h of 0 worked
Dollar used: Blue · 1.450

Also on the bench

Smaller worlds, still under construction, every one a real codebase. Nivelate is a growth journal with game spirit: six life areas, XP, 48 missions and levels that never drop, live as a PWA. Desvío is an isometric maze tower defense in Phaser where every sprite is generated in code. La Cuadra is a 3D boarding-house tycoon in Godot where tenants remember and gossip is reputation, with a sim core under 58 headless tests. Talle takes a job posting and tailors your CV to it with an honest fit score, and never invents experience.

Building something?

I'm open to remote product-engineering roles and short, well-scoped freelance builds. I take a product from idea to production and then keep it running, the same way I run my own.

sebastianelustondo@gmail.com

Buenos Aires, Argentina · remote · GMT-3 · LinkedIn · Résumé (PDF)

Don't read my portfolio.Play it.

Sebastián Elustondo

Experience

Stack

Education and languages

Products I built and operate myself

Barbería Hestia

Lead 0

Contactado 0

Cerrado 0

Cobrado 0

Also on the bench

Building something?

Don't read my portfolio.
Play it.