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{ JT }Jonathan Gamez Tomoyosi
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Jonathan Gamez Tomoyosi

Fullstack Developer

Fullstack developer working from data modelling through to the interface. I build with Python and Next.js on PostgreSQL, with infrastructure on AWS and Docker — from Big Data pipelines and tax-document systems to end-to-end web and mobile applications. I have concrete results in processing speed, project structure, and in turning raw data into information management can actually act on.

São Caetano do Sul, SP — Brazil

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Jonathan Gamez Tomoyosi

About

Who is behind the code

I am curious by nature and stubborn with a hard problem. I started out with hardware and networks, spent time in technical support, and that is where I learned the thing I use most today: listen to whoever will use the system before deciding how it should work.

That changed how I write code. My work now usually spans both ends — the database that has to hold up under volume, and the screen a non-technical person will open on their phone. I like documented projects, explained decisions, and code someone else can take over without having to call me.

I communicate clearly, work well in a team and adapt quickly to new context: I came from technical support into fullstack development and today I am also responsible for the projects’ AWS infrastructure.

Deliver solutions that improve business management, data structure and performance, while continuously raising the design and experience delivered to users.

  • Systems design
  • Data analysis and processing
  • AWS infrastructure
  • UI/UX
  • Agile methodology
  • Teamwork

Tech stack

Only what the code proves — each item states where it was used

Languages

  • TypeScript

    Default across every web and mobile project

  • Python

    Data processing, ETL and serverless functions

  • JavaScript

    Node services and automation scripts

  • PHP

    Maintaining and evolving a Laravel API

  • SQL

    Modelling, analytical queries and tuning

Frontend

  • Next.js

    App Router and server rendering in production

  • React

    UI of every panel and site

  • React Native · Expo

    Native application with Android builds

  • Tailwind CSS

    Default styling system

  • Radix UI · shadcn/ui

    Accessible components in admin panels

  • TanStack Query

    Server-state cache and synchronisation

  • React Hook Form · Zod

    Forms with schema validation

  • Recharts · Chart.js

    Management charts and dashboards

  • Leaflet

    Maps and heat maps

  • Motion

    Interface animation

Backend

  • Node.js

    APIs and supporting services

  • Fastify

    API with schema-validated contract and Swagger

  • FastAPI

    Python data services

  • Laravel

    Legacy API under maintenance and evolution

  • Prisma

    ORM and migrations in Node services

  • Drizzle

    Typed data-access layer

  • JWT · NextAuth

    Authentication and session handling

  • Opossum

    Circuit breaker on external dependencies

Data

  • PostgreSQL

    Primary database in nearly every project

  • Supabase

    Managed Postgres, auth and access policies

  • Firebird

    Legacy database integrated and migrated

  • pandas · NumPy

    Large-volume data cleansing

  • PyArrow

    Columnar format in data pipelines

  • Streamlit · Plotly

    Analytical dashboards

  • Selenium · BeautifulSoup

    Automated public-data collection

Infrastructure

  • AWS

    Lambda, EC2, RDS, S3, CloudWatch, ECR, SQS and Secrets Manager

  • Docker

    Containerisation and environment composition

  • Vercel

    Continuous deployment of Next.js applications

  • Keycloak

    Identity and access in internal dashboards

  • Sentry

    Production error monitoring

  • GitHub Actions

    Continuous integration

Quality

  • Vitest

    Unit and component tests

  • Testing Library

    User-behaviour-driven testing

  • Playwright

    End-to-end testing in a real browser

  • ESLint · Prettier

    Team-wide code standards

  • Git

    Branching flow, code review and commit convention

Experience

Where I applied it in practice

  1. Open Br

    Fullstack Developer

    Nov 2025 — present

    Corporate work

    End-to-end work on public-sector data platforms: from ingesting and processing large volumes through to the interface management uses to make decisions.

    • Built Big Data processing and cleansing routines, focused on cutting execution time.
    • Owned project infrastructure on AWS — serverless functions, instances, managed databases, object storage, observability and image registry.
    • Built systems for electronic invoice management and processing audit.
    • Data analysis and dashboards that turn raw databases into management indicators.
    • Responsible for the UX/UI of the projects.
    • Introduced new development methods and standards to the team.
    • Migrated legacy code and databases to current technology, including Firebird integration consolidated into PostgreSQL.

    Client and system names withheld for confidentiality. Happy to go into detail in conversation.

    • Python
    • pandas
    • PostgreSQL
    • AWS
    • Docker
    • Next.js
    • TypeScript
    • FastAPI
    • Laravel
    • Streamlit
    • Firebird

  2. Yma Log

    Mobile Developer

    Jan 2026 — present

    Responsible for the app’s design and structure, translating features designed for desktop into an experience that genuinely works on a small screen.

    • Design and structural improvements to the mobile application.
    • Ported web features to mobile with simple, fluid navigation.
    • Reduced friction in the transition from desktop screen to phone screen.
    • Native application in React Native with Expo, shipped for Android.
    • React Native
    • Expo
    • TypeScript
    • Fastify
    • Prisma
    • PostgreSQL

  3. Igreja Bom Pastor SP

    Fullstack Developer

    Church management system built end to end — from the data model and permission rules to the mobile-first interface members actually use.

    • Full finance module, with cash in/out management.
    • Pastoral management: birthdays, the groups each member belongs to, and tithe status.
    • Service rota management for members, with notices.
    • Calendar with event control, responsible participants and email notification.
    • Reports for the children’s class teachers.
    • Complete authentication system with sign-up, password recovery and reset.
    • Next.js
    • React
    • TypeScript
    • Supabase
    • PostgreSQL
    • Tailwind CSS
    • Recharts
    • Vercel

Projects

Problem, technical decision and outcome

Igreja Bom Pastor SP

Igreja Bom Pastor SP

Live

Mobile-first church management platform, from database to interface

  • Next.js 15
  • React 19
  • TypeScript
  • Tailwind CSS 4
  • Supabase
  • PostgreSQL
  • +4
Read case studyView live

native Android app · web panel · documented API · push notifications

Yma — Plataforma mobile

In testing

Native app, admin panel and API — three fronts, one product

  • React Native
  • Expo
  • TypeScript
  • React Navigation
  • Fastify
  • Prisma
  • +5
Read case study

circuit breaker · rate limiting · retry with backoff · structured logging

Yma — E-commerce

In testing

Storefront with a resilient backend: circuit breaker, rate limiting and sanitisation

  • React
  • TypeScript
  • Vite
  • TanStack Query
  • Fastify
  • Prisma
  • +5
Read case study

Education and languages

Academic background

  • FIAP

    In progress

    MBA in Data Engineering

    Aug 2026 — present

  • Universidade Nove de Julho — Uninove

    Completed

    Technologist in Systems Analysis and Development

    Jan 2022 — Jul 2024

  • PortugueseNative
  • EnglishIntermediate
  • SpanishIntermediate

Contact

Let’s talk

Email

jonathan.tomoyosi@gmail.com

Phone

(11) 94086-4666

WhatsApp

(11) 94086-4666

LinkedIn

/in/jonathan-gamez-tomoyosi

GitHub

@jonathan-tomoyosi

Location

São Caetano do Sul, SP — Brazil