TiagoCastro

Building and evolving sites, systems and products.Building and evolving websites, systems and digital products.

For over 6 years I have built systems that must keep running while they grow.For over 6 years I have built systems used by companies, clients and teams that must keep running while they grow.

Sites and systems · screens, payments and integrations
Online structure · speed, security and costs
Information · organizing, processing and analysis
Growth · Google search and automated tasks

View experience Talk to me

Working now

HITSS · LakeIT Project

Fullstack Cloud Developer · Jan/2024 - present

Data platform with processing, queries and AWS infrastructure.

Futbuynow

Freelance · Feb/2023 - present

Marketplace in production with payments, SEO and automations.

Complete professional history.

GitHub

Open source and authorial projects.

Sites and systems · screens, payments and integrations
Online structure · speed, security and costs
Information · organizing, processing and analysis
Growth · Google search and automated tasks

Professional experience

Each job shows the context I found, what I changed, why I changed it and the results tracked along the way.

Jan/2024 - present

Fullstack Cloud Developer

HITSS · LakeIT Project

Data platform used by companies to organize, process and query large volumes of information.

I automated data preparation into pipelines

Automatic flows that prepare information without manual work.

Dozens of flows in use by clients

I split a complex structure into smaller parts

I reorganized the structure into smaller parts, repeatable across environments.

+29 reusable parts in +3 environments

I turned questions into answers and charts

Questions in plain language become queries, answers and charts.

Answers and charts in natural language

I reorganized the cloud structure to reduce costs.

I reviewed components and environments to cut waste and make future changes safer.

Before> US$ 2,300 / month

After~ US$ 800 - 1,000 / month

+ US$ 15k / year

estimated yearly savings

From data to digital commerce.

Different contexts demand different decisions, but both need to keep working while they change.

Information ready to use
Costs and risks under control
Sales in motion

Feb/2023 - present

Client · Freelance Technical responsibility

Futbuynow

Marketplace in production with purchasing, payments, vendors and daily operation.

~3,407

paid orders / month

May-Jul/2026

+65,000

orders processed

accumulated volume

+84%

clicks coming from Google search

Jun → Jul/2026

+30.4k

clicks from Google in 12 months

Operation evolution after I took technical leadership

Oct-Dec/2023

~1,483 / month

May-Jul/2026

~3,407 / month

I restructured the purchase journey

I track vendors, affiliates, commissions and loyalty across the panel and checkout.

I connected payment and confirmation

Payment connected to the order and loyalty program, with no manual checks.

I automated operational analysis

Reports and click analysis that guide interface improvements.

Authorial and study projects.

Everything here came from my own hands: built, learned and documented. Code, interface and architecture decisions open for anyone to dig into.

Authorial project

NexSift

Technology radar that filters and contextualizes signals with verified sources. There I deepened production Next.js, publishing through an authenticated Zod-validated Lambda and S3 infrastructure described in Terraform.

Next.js · TypeScript · AWS · Terraform · MCP · IA

Website GitHub

NexSift home page with the message Less noise, more signal and four recent signals — Figure 1. Home page: product proposal and a short selection from the radar, with no infinite feed.

Mobile version of NexSift showing three recent signals and their relevance scores

Reading stays short on mobile.

The same radar hierarchy was preserved in a single column: title, relevance and date come before context.

NexSift signal archive with the post list and topic filters — Figure 2. The signal archive gathers the publication history with topic filters.

NexSift topics page organized in seven technology areas — Figure 3. Seven editorial lenses organize what the product tracks.

Authorial project · Open Source

Kaguya

Learning platform with study trails, playlists and video lessons. It is where I learned, hands on, Clean Architecture on the Express API, dependency injection, permission level RBAC and GraphQL Federation.

Next.js 15 · React 19 · Express · NestJS · GraphQL Federation · Prisma 6 · PostgreSQL · TypeScript · Firebase Auth · Zod

Created August 2021 · Restored August 2026

GitHub

Student dashboard listing ongoing trails and the progress of each one

Authorial project · 2026 restoration

The Monkeynauts

Play and earn game from 2022 that I restored from scratch applying Clean Architecture, Either for explicit errors and strict TypeScript, with a pluggable driver between sandbox and real BSC blockchain and E2E across all 55 routes.

React 19 · Vite · Express 5 · Prisma 6 · PostgreSQL · ethers v6 · TypeScript strict · zod · Docker

Created December 2021 · Restored August 2026

GitHub

The Monkeynauts player area showing wallet, balance and account details

Study project · Open Source

pagarme-simplified-psp

Payment service inspired by the classic Pagar.me challenge where I trained SOLID, TDD and DDD hands on: debit and credit with scheduled payables, value objects with Either and balances covered by Vitest tests.

Created April 2023 · Restored August 2026

GitHub

NPM · Open Source

ai-i18n-translate

Tool published on npm that translates i18n files with AI without breaking placeholders. With it I learned translation caching, parallel processing, retry with backoff and automatic key validation.

Created March 2026

npm GitHub

Open Source

AWS IaC Blueprint

Infrastructure as code where I learned to structure Terraform and Terragrunt at scale: modules without hardcoded values, identical environments in a single env.hcl and a full cycle on LocalStack at no cost.

Created May 2026

GitHub

Study project · Open Source

ig.news

Subscription blog from the Ignite program that I modernized in 2026: Stripe with signed webhook, next-auth, ISR from Prismic, FaunaDB to Prisma migration and Playwright E2E tests.

Created May 2022 · Restored August 2026

GitHub

Study project · Open Source

Let Me Ask

Real time Q&A rooms from NLW 6 that I restored with Firebase Auth and Realtime Database, security rules for unique likes, live moderation and validation with react-hook-form and Zod.

Created June 2021 · Restored August 2026

GitHub

Full projects page

Want to see each project in detail?

The projects page gathers context, dates, stack and what I learned building each one.

View projects