Services · custom projects
Systems and automations built around your business.
I'm Guilherme Yuji, a developer and data engineer in São Paulo, Brazil. Since 2022 I've delivered custom systems for small businesses — and, on the Vivo project, I build automations that validate and monitor data at scale.
- 15clients served end to end
- 2022the year I shipped my first client system
- 30xfaster on an automated validation
- −70%time spent on a daily check
What I do
Four kinds of project — from a complete system to automating the one task that eats your team's hours.
- 01
Custom systems
Records in spreadsheets, paper notebooks, information scattered across WhatsApp.
A web system built around how your business works: from mapping the routine with your team to a live system, with support after delivery.
In practiceAbout 15 clients served since 2022 — auto repair shops, optical stores and service companies.
Next.js · React · TypeScript · PHP · Docker
- 02
Process automation
Repetitive work — checking data, copying between systems, building reports — taking hours of your team's day.
Automated Python routines and API integrations that do the repetitive work and flag anything out of the ordinary.
In practiceOn the Vivo project, a 3–4 hour daily check dropped to under 1 hour, and a validation became 30x faster.
Python · SQL · REST APIs
- 03
Data and dashboards
The numbers exist, but nobody trusts them — or nobody can see them.
Organized, validated data, Power BI dashboards, and monitoring that warns you when a load is late or a dashboard breaks.
In practiceMonitoring for ~70 data projects on the Vivo project: ~60 incidents caught in the first 4 months.
Power BI · SQL · Databricks · PySpark
- 04
AI agents
Customer service, triage and lookups that repeat all day long.
AI agents and chatbots that automate steps of customer service and internal processes.
In practiceI lead the AI agents initiative for Vivo at Engineering Brasil, with Python and LangGraph.
Python · LangGraph · OpenAI APIs
How it works
The same road on every project, from the first conversation to support after delivery.
Requirements
A conversation to understand how your business runs and what needs to change — in your language, no jargon.
Design
The blueprint: screens, flows and data, agreed with you before any code is written.
Development
The build, with the right technology for the size of the project.
Deploy
The system goes live on a server, ready for your team to use.
Support
After delivery: tweaks, questions and improvements as the business grows.
Frequently asked questions
How much does a project cost?
It depends on the size and what needs to be built. After the first conversation you get a proposal with scope, timeline and price — no strings attached.
Do I need to understand technology?
No. We talk about your business; the technical side is on me, from requirements to a live system.
What happens after the system goes live?
I stay close: post-delivery support for tweaks, questions and improvements.
How do we start?
Tell me what you need in the form below (or by email). I'll reply to set up a conversation.
Tell me about your project
Three quick questions. The message comes out ready in your email — just review and send.
Rather talk directly?
I reply by email and on LinkedIn.