Elson Otake

Software Engineer

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About

Elson Otake

Here is a little background

Ruby on Rails developer with production experience building and maintaining fintech payment applications using Ruby on Rails and PostgreSQL. My day-to-day work includes Ruby on Rails, PostgreSQL, REST APIs, and RSpec, with a strong focus on automated testing, code review, clean architecture, and maintainable code. I have hands-on experience with payment flows involving boletos, Pix, bank remittances, and integrations with multiple Brazilian banking providers. My career path is a bit different. I started as a Systems Engineer at Fujitsu, working with online transactions, data security, and databases, before returning to software development as a self-taught developer. This background gives me solid systems and business fundamentals combined with current, hands-on software development experience. I have a Computer Science foundation through Applied Mathematics at the University of São Paulo and experience working in remote agile teams. I enjoy solving complex problems, collaborating across engineering, product, and design, and continuously improving the quality of the systems I work on.

Experience

Swipe or click arrows to explore career milestones

Kobana Tecnologia

Ruby on Rails Developer

Kobana Tecnologia

Ruby on Rails
PostgreSQL
Claude
n8n
Zapier
Hotwire
Sidekiq
VS Code
Swagger
HTML
CSS
Javascript
React
GitHub

Thu Mar 21 2024 – Fri Aug 14 2026

  • Build and maintain features for a Brazilian fintech payments platform (boletos, Pix, bank remittances) using Ruby on Rails, PostgreSQL, and Hotwire/Turbo.
  • Integrate with multiple banking providers (Itaú, Santander, Caixa, Sicredi) for charge and Automatic Pix flows, including CNAB remittance processing.
  • Write comprehensive tests (RSpec) and participate in code review to keep the codebase clean and maintainable.
  • Apply AI-assisted workflows (Claude Code, n8n) to accelerate development and automation.
I-Spire Enterprises Ltd

Ruby on Rails Developer

I-Spire Enterprises Ltd

Ruby on Rails
PostgreSQL
Hotwire
Sidekiq
VS Code
GitHub
HTML
CSS
Javascript

Tue Mar 21 2023 – Thu Dec 21 2023

  • Maintained and extended a dental care platform for appointment scheduling and client records, fixing bugs and shipping new features on a Ruby on Rails codebase.
  • Built a location-based marketplace from the ground up, letting users trade products and services by proximity — integrated the Google Maps API for geolocation, search, and mapping.
  • Developed a subscription app for recurring delivery of fresh-produce baskets (fruits and vegetables), including subscription plans and order management.
  • Worked remotely with an international team, delivering across three products during the contract.
Fujitsu do Brasil

System Engineer

Fujitsu do Brasil

Javascript
HTML
CSS

Mon Dec 01 1986 – Sun Dec 15 1996

  • Choose to participate in the company's worldwide project aimed at the cultural interactivity of Japanese employees among all engineers.
  • Invite to work at the headquarters in Tokyo for 15 months performing software support to company customers.
  • Main presenter in exhibitions across the country. Present equipment and application.
  • Support and training to the company's proprietary software customers.
MIcroverse Inc

Code Reviewer

MIcroverse Inc

Ruby
Ruby on Rails
React
Javascript
PostgreSQL
HTML
CSS
VS Code
GitHub
Sidekiq
Swagger

Mon Aug 01 2022 – Mon May 15 2023

  • Reviewed pull requests from students in Microverse's remote full-stack program, giving actionable feedback on code quality, testing, algorithms, and best practices across Ruby, Rails, JavaScript, and React.
  • Helped developers refactor toward cleaner, more efficient, better-tested code, and clarified concepts to unblock them.
  • Mentored across time zones in a fully remote setting, reinforcing industry-standard Git workflow and professional communication.
  • Chosen by peers as Top Collaborator (October 2022) for consistent, high-quality contributions.

Skills

Tap a skill for current proficiency

n8n

86%

Sidekiq

78%

React

75%

Swagger

81%

Ruby

85%

Hotwire

78%

VS Code

78%

HTML

82%

GitHub

75%

Ruby on Rails

86%

Python

74%

Claude

80%

CSS

80%

Zapier

84%

PostgreSQL

84%

Javascript

86%

Projects

Covid 19

Case Study 1 of 4 : Covid 19

React
VS Code
HTML
Javascript
CSS
GitHub

Covid 19 is a web application presenting numerical metrics and interactive charts about the COVID-19 pandemic across South America. Built with React 18, Redux Toolkit, and Vite, powered by official World Health Organization (WHO) datasets.

Family Tree

Case Study 2 of 4 : Family Tree

Ruby on Rails
PostgreSQL
Javascript
Hotwire
Swagger
Claude
n8n
HTML
CSS
VS Code
GitHub

Family Tree is a Ruby on Rails application for managing family relationships.

Stripe

Case Study 3 of 4 : Stripe

Ruby on Rails
PostgreSQL
Javascript
HTML
CSS
VS Code
GitHub

This app handles products hosted on Stripe. It performs payments, subscriptions, and billing.

Exo Cars

Case Study 4 of 4 : Exo Cars

Ruby on Rails
React
PostgreSQL
Swagger
HTML
CSS
VS Code
GitHub
Javascript

Exo Cars is an exotic car rental website. It allows users to sign up, view available cars, and make reservations. React consumes data from a Ruby on Rails API.

Contact

Looking for the right fit for your team? Let's Talk.

+55 (11) 99749-6626
elsonotake@gmail.com

Brazil - São Paulo - SP