Yenson Umaña. Senior AI Solution Architect. I build products from scratch and advise startups on production AI.

Two products I run today

Presencia StudioListo

Presencia Studio

Web pages, digital business cards, QR menus and loyalty cards for small businesses in Costa Rica.

1/4 Home

Open presencia.studio

Listo

Home repairs in Guanacaste: describe the job, get a quote from a vetted technician, pay by card or SINPE.

1/4 Home

Open usalisto.com

Presencia Studio

Founded in 2025 and built from scratch on Next.js 16, Supabase and Vercel: hosted profiles, QR menus merchants edit from their phone, loyalty cards customers keep in their wallet with a staff scanner, ONVO payments, Spanish first with English.

Decisions you can see in the product

Merchants change their own prices and menus; the printed QR never changes.
Every loyalty stamp is validated by an authorized person, never by the customer.

Open presencia.studio

Listo

Launched in 2026 and built from scratch: the web app on Next.js 16 and Supabase, a WhatsApp quoting flow, customer and provider emails, ONVO card and SINPE payments, and the admin that confirms them.

Decisions you can see in the product

Quotes are made per job, never from a price list.
A technician's contact is shared only after the payment is confirmed.
Requesting offers is free and needs no WhatsApp account.

Open usalisto.com

Also built

AOP Beacon
NFC beacons at live-event tables open an AI conversation prompt. The model gets four seconds, then a curated prompt takes over, and names never reach the model.
Source on GitHub
Vercel + GCP to Azure in one week
A startup's full production migration, run with Claude Code and MCP as Microsoft for Startups advisory. One cutover, an acceptance gate per subsystem.