Software engineer · Portfolio

Giovanni Santillan Richaud

Full-stack .NET engineer building production systems — payments, identity, and AI-augmented software.

Experience

15+ years

Core stack

C# · .NET · SQL Server

Full-stack

TypeScript · React · Next.js

Backend & data

EF Core · Supabase · Azure

Focus

Payments · Identity · AI agents

Based

Toronto · México — remote

I design and ship products end to end — from database and APIs to production deployment and support. Fifteen years in commercial .NET / SQL Server real-estate platforms, plus a set of personal builds where I push the same rigor into payments, authentication, and AI-driven pipelines. I work AI-first: agentic coding is part of how I build.

Selected work

Three-stack build Live demo

Rent.ca

A public demo of a Canadian rental marketplace — built three times, in .NET, in Next.js and in Angular, to prove the same product across three stacks. Seed data; the engineering is the point.

Highlights

Google Maps split-view with marker clustering and bidirectional hover-sync between pins and list cards.
AI assistant with real tool-calling — searches the live database, returns property details and city info, and saves alerts.
Landlord and renter portals with role-gated routing; 5-step listing builder and inquiry inbox.
Bilingual EN/FR, dark mode, and money handled in integer cents across DB, map, and AI layers.

Three stacks

.NET — primary

.NET 9ASP.NET CoreRazor PagesEF Core 9SQL ServerIdentity + Google OAuthAzure App ServiceGitHub ActionsxUnit

Angular — latest build

Angular 22SSRStandalone componentsTypeScriptTailwind.NET 9 Web APIEF Core 9Azure SQLPlaywright E2EGitHub Actions (OIDC)

Next.js — first build

Next.js 16React 19TypeScriptSupabasePostgreSQLVercel AI SDKOpenRouterZustandTailwind

Live

.NET version Angular version Next.js version

Source

.NET — GitHub Angular — GitHub Next.js — GitHub

Production SaaS · own product Live

CondoAdmin — TuCondoAdmin.com

My own SaaS for condominium administration in Mexico — a real product with real payments. This is where I keep production money-handling honest.

Highlights

Production payment webhooks with HMAC-SHA256 signature verification (MercadoPago) and Standard-Webhooks validation (Polar), using constant-time comparison.
Fast-ACK plus background processing to avoid provider retries, with idempotent reconciliation (dedup by external reference / webhook id) and a cron safety-net that trues-up missed events.
Automatic commission accounting so the ledger always matches the payment account, plus SPEI bank-transfer reconciliation.
Google OAuth (PKCE) and mandatory TOTP two-factor enforced in middleware for privileged roles; multi-tenant with resident / treasurer / admin / platform-admin roles.

Stack

Next.js 16React 19TypeScriptSupabasePostgreSQL · RLSMercadoPagoPolarResend + React EmailWhatsAppVercel AI SDK

Live

tucondoadmin.com

Capabilities

from the work above

Languages & frameworks

C# / .NETASP.NET Core (MVC & Razor Pages)TypeScriptReactNext.js

Data

SQL ServerEF CorePostgreSQL / SupabaseZod

Payments & identity

Payment webhooks (HMAC)OAuth 2.0 / PKCETOTP 2FAIdempotent reconciliationMulti-tenant / RBAC

AI & cloud

Agentic tool-callingVercel AI SDKOpenRouterAzure App ServiceVercelGitHub Actions

Get in touch

Let's build something reliable.

Open to remote roles and contracts across North America. Happy to walk through any of the systems above.

gio.richaud@gmail.com linkedin.com/in/giovanni-santillan-richaud github.com/grichaud