Five years of C#, .NET, React and TypeScript — mostly backend services and the frontends that live on top of them. Right now I do that for US product teams at Praxent, and on the side I co-founded AgenLink, a scheduling app shipping on both stores.
I like the unglamorous parts: clean architecture that survives the second year, queries that stop being slow, production bugs that turn out to be three services deep.
A scheduling platform for independent professionals in Brazil — hairdressers, lawyers, personal trainers, tattoo artists. Clients book themselves from a public link, reminders go out over WhatsApp, and everything stays in sync with Google Calendar. I co-founded it with a friend and built it end to end.
PROBLEM
Autonomous professionals run their agenda out of a WhatsApp thread. Double bookings, no-shows, and Sunday nights spent sorting out the week.
BUILT
Public booking pages, automatic rescheduling and cancellation, WhatsApp reminders, two-way Google Calendar sync, subscription billing, and the mobile app on both stores.
MY PART
Co-founder and engineer. Architecture, API, app, deploys, and the boring decisions in between.
STACK
TypeScript
React
React Native
Node.js
PostgreSQL
Google Calendar API
AWS
MORE RECORDS COMING — CLIENT WORK UNDER NDA FOR NOW.
02 — Experience
Where I've worked
Open a row for what the job actually involved.
DATESROLECOMPANY
Senior Software EngineerPraxent · Remote
—Design and build SaaS backend services in C# and .NET, leaning on clean architecture so the second year is cheaper than the first.
—Build React front ends in TypeScript with shadcn/ui and reusable component architecture.
—Own backend design decisions and REST APIs consumed by several clients.
—Chase down production issues across distributed systems and optimise the SQL underneath.
C#
.NET
React
TypeScript
SQL Server
Systems design
Software EngineerPraxent · Austin, TX
—Bootstrapped full-stack .NET and React applications from empty repo to scalable foundation.
—Wrote documentation and recorded walkthroughs so client teams could take the code over.
Full Stack DeveloperMelhorplano.net
—Led architecture on a high-traffic, SEO-critical platform, including server-rendered .NET for page speed.
—Ran the AWS side — CloudFront, ECS, S3 — with an eye on cost as well as uptime.
—Mentored junior developers and rewrote onboarding so it stopped taking a week.
Mid Level Full Stack DeveloperThreeo IT · São Paulo
—Modernised legacy web systems built on jQuery, Knockout.js and Durandal without stopping the business.
—Built and maintained REST APIs on server-rendered .NET architectures.
Software DeveloperiDinheiro
—Migrated a legacy WordPress front end to React and Next.js with TypeScript.
—Moved Core Web Vitals in the right direction and shipped A/B tests with the marketing team.
—Added Jest unit and integration coverage where regressions kept happening.
React Full Stack DeveloperRDS Digital · Freelance
—Node.js and Express APIs behind a user management system, with a React web client.
—Shipped the companion React Native app for mobile access.
03 — Toolkit
What I reach for
Backend
C#
.NET
REST APIs
Clean architecture
Node.js
NestJS
Systems design
Frontend
React
TypeScript
Next.js
React Native
shadcn/ui
Core Web Vitals
Cloud & data
AWS EC2
ECS
S3
CloudFront
SQL Server
PostgreSQL
Query optimisation
How I work
Distributed teams
Jest
Git workflows
Technical writing
Mentoring
Claude Code
04 — Contact
Tell me what you're building.
If you're hiring for a full stack or backend role, or you need someone to take a .NET and React product further than it is now, write to me. I read everything and answer in English or Portuguese.
TOBIAS ROSA · SENIOR FULL STACK ENGINEERBUILT WITH .NET HABITS AND TOO MUCH COFFEE · 2026