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Hello! I'm a Senior Software Engineer based in Tokyo, delivering scalable, secure, and high-performance systems. I specialize in building robust backend services with Node.js, Ruby on Rails, and Python, designing RESTful and GraphQL APIs, and crafting efficient database architectures. I'm also hands-on with frontend development using React, Next.js, and Vue.js, and I deploy cloud-native infrastructure on AWS and GCP with Kubernetes and Docker to create resilient, cost-effective solutions. I routinely implement CI/CD, monitoring, and observability to keep production operations smooth. I stay on top of industry trends, write clean, maintainable code, and focus on scalability, reliability, and engineering best practices. I collaborate across teams and am comfortable working in remote-and-global environments.…Hello! I'm a Senior Software Engineer based in Tokyo, delivering scalable, secure, and high-performance systems. I specialize in building robust backend services with Node.js, Ruby on Rails, and Python, designing RESTful and GraphQL APIs, and crafting efficient database architectures. I'm also hands-on with frontend development using React, Next.js, and Vue.js, and I deploy cloud-native infrastructure on AWS and GCP with Kubernetes and Docker to create resilient, cost-effective solutions. I routinely implement CI/CD, monitoring, and observability to keep production operations smooth. I stay on top of industry trends, write clean, maintainable code, and focus on scalability, reliability, and engineering best practices. I collaborate across teams and am comfortable working in remote-and-global environments.

Yusuke Doi

Front-End Developer, Back-End Developer, Web Developer, +3

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Hello! I'm a Senior Software Engineer based in Tokyo, delivering scalable, secure, and high-performance systems. I specialize in building robust backend services with Node.js, Ruby on Rails, and Python, designing RESTful and GraphQL APIs, and crafting efficient database architectures. I'm also hands-on with frontend development using React, Next.js, and Vue.js, and I deploy cloud-native infrastructure on AWS and GCP with Kubernetes and Docker to create resilient, cost-effective solutions. I routinely implement CI/CD, monitoring, and observability to keep production operations smooth. I stay on top of industry trends, write clean, maintainable code, and focus on scalability, reliability, and engineering best practices. I collaborate across teams and am comfortable working in remote-and-global environments.…Hello! I'm a Senior Software Engineer based in Tokyo, delivering scalable, secure, and high-performance systems. I specialize in building robust backend services with Node.js, Ruby on Rails, and Python, designing RESTful and GraphQL APIs, and crafting efficient database architectures. I'm also hands-on with frontend development using React, Next.js, and Vue.js, and I deploy cloud-native infrastructure on AWS and GCP with Kubernetes and Docker to create resilient, cost-effective solutions. I routinely implement CI/CD, monitoring, and observability to keep production operations smooth. I stay on top of industry trends, write clean, maintainable code, and focus on scalability, reliability, and engineering best practices. I collaborate across teams and am comfortable working in remote-and-global environments.

Available to hire

Hello! I’m a Senior Software Engineer based in Tokyo, delivering scalable, secure, and high-performance systems. I specialize in building robust backend services with Node.js, Ruby on Rails, and Python, designing RESTful and GraphQL APIs, and crafting efficient database architectures. I’m also hands-on with frontend development using React, Next.js, and Vue.js, and I deploy cloud-native infrastructure on AWS and GCP with Kubernetes and Docker to create resilient, cost-effective solutions. I routinely implement CI/CD, monitoring, and observability to keep production operations smooth.

I stay on top of industry trends, write clean, maintainable code, and focus on scalability, reliability, and engineering best practices. I collaborate across teams and am comfortable working in remote-and-global environments.

Skills

Experience Level

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Language

English

Fluent

Japanese

Intermediate

Work Experience

Junior Frontend Engineer at TRuFlation

April 1, 2017 - September 19, 2025

Joined frontend team to develop UI using React.js (v16), React Native, and Bootstrap 3; performed UI/UX improvements, tracked performance with Google Analytics, and released 40+ UI components. Collaborated with Backend to support transaction pagination and data display (AmChart), improving user experience and SEO metrics (FCP/LCP).

Junior Software Engineer at TRuFlation

December 1, 2019 - September 19, 2025

Coordinated with backend to optimize RESTful APIs, implemented efficient data models with Sequelize, and introduced Redis caching on Heroku. Built E2E tests with Cypress and Jest for data access and business logic, reducing data retrieval times and improving reliability.

Intermediate Software Engineer at WIX

December 1, 2021 - September 19, 2025

Refactored backend codebase to modularize thousands of lines of code, integrated GraphQL for real-time data display, and migrated CI/CD pipelines to Azure DevOps. Managed AWS IAM permissions, implemented daily CloudWatch/GA-basedNotifiers, and designed scalable load balancing with Auto Scaling Groups to ensure high availability.

Intermediate Backend Engineer at PayPay

December 1, 2022 - September 19, 2025

Integrated PayPay card payments as a payment gateway, monitored production and data usage to optimize transaction timing, redesigned 50+ CRUD operations, and maintained database infrastructure (monitoring, backups, migrations). Created documentation and data models to improve cross-team collaboration.

Senior Software Engineer at betcloud

January 1, 2023 - Present

Engineered flagship iGaming Casino and Sportsbook platform with 120+ reusable UI components; designed real-time data pipelines for odds and wallet balances via RESTful APIs and WebSockets; built CMS features, admin dashboards, and fraud monitoring tools; deployed and scaled applications with Docker and AWS, collaborating with DevOps for high availability.

Junior Frontend Engineer at TRuFlation

April 1, 2017 - September 19, 2025

Frontend development using React.js (v16.0), React Native (v0.70), ES2017, Bootstrap 3, Figma, Trello, Jest, React-testing-library, Code Review, Github. Started the career with documentation and production analysis to gather user performance feedback, implementing 40+ UI components and optimizing UX, including improvements to FCP/LCP and SEO. Collaborated with Backend team on complex Front-End features and third-party API integrations for real-time data.

Junior Software Engineer at TRuFlation

December 1, 2019 - September 19, 2025

Backend-focused role using Express, Node.js, JavaScript, MySQL, JWT, RESTful APIs, Sequelize, Redis, Postman, Cypress, Jest, Docker, Kubernetes, PM2, Heroku. Optimized data model and query performance; collaborated with Frontend to ensure seamless API integration; implemented Redis optimizations on Heroku to prevent production outages; developed E2E tests with Cypress and Jest.

Intermediate Software Engineer at WIX

December 1, 2021 - September 19, 2025

Backend development with JavaScript, Python, Django; PostgreSQL, GraphQL. Refactored backend to follow Agile practices and SOLID/DRY principles; integrated real-time data via GraphQL; migrated CI/CD pipelines to Azure DevOps; implemented daily notifications via AWS CloudWatch and Google Analytics; managed AWS IAM access and security practices.

Intermediate Backend Engineer at PayPay

December 1, 2022 - September 19, 2025

Delivered backend services for PayPay card payments; monitored production logs and data usage to optimize transaction estimates; designed and migrated database structures; implemented 50+ CRUD operations; documented architecture and procedures; worked primarily with Ruby on Rails, PostgreSQL, and AWS services.

Senior Software Engineer at betcloud

January 1, 2023 - Present

Engineered flagship iGaming Casino and Sportsbook platform using Django and Next.js; built 120+ reusable components; integrated real-time cryptocurrency data from OKEX, Uniswap, and Binance; implemented CMS features and admin access controls; deployed with Docker and AWS (EC2/ELB/S3/IAM); established real-time data pipelines with WebSockets and Redis; designed scalable PostgreSQL schemas.

Junior Frontend Engineer at TRUFLATION

April 1, 2017 - September 19, 2025

Frontend focused role using React.js (v16.0) and React Native; contributed to component styling updates and UI/UX improvements based on performance feedback, integrating third‑party APIs for real‑time data and collaborating with Backend teams on features such as transaction pagination and data visualization.

Backend Engineer at TRUFLATION

December 1, 2019 - September 19, 2025

Collaborated with Senior Backend Developers to optimize data models and query builders with Sequelize; reduced frontend data retrieval times by ~30%; improved Redis usage on Heroku for resilience; developed End‑to‑End tests with Cypress and Jest for data access and business logic.

Intermediate Software Engineer at WIX

December 1, 2021 - September 19, 2025

Backend codebase refactoring, Agile/SOLID/DRY adoption, and GraphQL integration; transitioned CI/CD pipelines to Azure DevOps; managed AWS IAM and security practices; implemented daily production indicators and region-aware load balancing with Auto Scaling.

Intermediate Backend Engineer at PAYPAY

December 1, 2022 - September 19, 2025

Backend engineering and database administration for payments platform; integrated PayPay card payment gateway; detailed production and data usage logging; redesigned table relationships and created 50+ CRUD operations; authored architecture docs.

Senior Software Engineer at BETCLOUD

January 1, 2023 - Present

Engineered flagship iGaming platform; delivered 120+ reusable components; integrated real‑time crypto data (OKEX/Uniswap/Binance); implemented WebSockets and TypeScript skeleton rendering; built CMS features, dashboards, admin access control, and production deployments with Docker/AWS.

Junior Frontend Engineer at TRUFLATION

April 1, 2017 - September 19, 2025

Started the career with frontend development focusing on React.js and React Native; analyzed user performance via Google Analytics; implemented 40+ UI components; debugged and improved UX including FCP/LCP; collaborated with Backend to integrate real-time data; implemented features with third-party APIs; contributed across the frontend team.

Intermediate Software Engineer at WIX

December 1, 2021 - September 19, 2025

Maintained and updated backend codebase; refactored code following SOLID/DRY; modularized 2000+ and 3000+ one-file codebases into 100+ files; integrated GraphQL for real-time data; migrated CI/CD pipelines to Azure DevOps; managed AWS IAM; set up daily notifier via CloudWatch and Google Analytics; implemented regional load balancing and auto-scaling.

Intermediate Backend Engineer at PayPay

December 1, 2022 - September 19, 2025

Backend engineer and database administrator delivering payments integration with PayPay card; monitor production logs and data usage for optimized transaction times and bonuses; documented database relationships; managed day-to-day database operations including backups and migrations; designed 50+ CRUD data models; wrote ~30 testing scripts with RSpec.

Senior Software Engineer at BETCLOUD

January 1, 2023 - Present

Engineered flagship iGaming platform across multiple themes; built 120+ reusable UI components; designed RESTful APIs and real-time data feeds for cryptocurrency; implemented Skeleton loading with TypeScript; created CMS features for backoffice; built internal dashboards for marketing and customer service; implemented real-time data processing with WebSockets/Redis; designed PostgreSQL schemas; collaborated with DevOps on Docker and AWS.

Junior Frontend Engineer at TRUFLATION

April 1, 2017 - September 19, 2025

Worked with React.js (v16.0) and React Native (v0.70), ES2017, Bootstrap 3, and Figma to deliver frontend features. Enabled component-level performance improvements, implemented 40+ UI components, and collaborated with Backend to integrate real-time data from third-party APIs. Debugged issues with Chrome DevTools to improve core metrics (FCP/LCP) and SEO insights, supporting UI updates and feature releases.

Junior Software Engineer at TRUFLATION

December 1, 2019 - September 19, 2025

Moved into backend collaboration with Express, Node.js, JavaScript, MySQL, JWT, RESTful APIs, Sequelize, Redis, Postman, Cypress, Jest, Docker, Kubernetes, PM2, and Heroku. Contributed to data model optimization, improved API performance, and helped implement robust testing and deployment practices; collaborated with frontend teams to accelerate data retrieval and ensure seamless API integration.

Intermediate Software Engineer at WIX

December 1, 2021 - September 19, 2025

Worked on backend codebase using JavaScript, Python, Django, Jest, PostgreSQL, Sequelize, GraphQL, JWT, bcrypt, Firebase, Redis, NGINX, AWS S3/EC2/ASG, Azure DevOps, AWS RDS/Load Balancer/CloudWatch/IAM. Refactored large codebase toward SOLID/DRY principles, modularized 2000+ and 3000+ one-file sets into 100+ files, integrated GraphQL for real-time data, and migrated CI/CD pipelines to Azure DevOps to enhance maintainability and scalability.

Intermediate Backend Engineer at PAYPAY

December 1, 2022 - September 19, 2025

Delivered backend services and database administration to integrate PayPay card payments across web and app platforms. Monitored production and data-usage logs to optimize transaction timing estimates and bonuses. Managed database operations, migrations, backups, and performance tuning; redesigned data models and authored 50+ CRUD operations with robust tests and documentation.

Senior Software Engineer at BETCLOUD

January 1, 2023 - Present

Engineered flagship iGaming Casino and Sportsbook platform with multi-theme support; built 120+ reusable components (date pickers, filters, file UIs, wallets, transaction history, modals). Designed RESTful APIs and third-party services for real-time cryptocurrency data, implemented TypeScript-based skeleton rendering to improve performance, and developed CMS features for backoffice operations. Implemented real-time data processing with WebSockets and Redis Pub/Sub, optimized PostgreSQL schemas, and collaborated with DevOps to deploy on Docker and AWS at scale.

Junior Frontend Engineer at TRUFLATION

April 1, 2017 - September 19, 2025

Prototyped and implemented UI components using React.js (v16) and React Native. Collaborated with backend to deliver data-driven UI, and implemented 40+ user-friendly UI components based on feedback; improved performance via Chrome DevTools, focusing on FCP/LCP and SEO improvements.

Junior Software Engineer at TRUFLATION

December 1, 2019 - September 19, 2025

Collaborated with backend team to optimize data model and query builders using Sequelize; reduced data retrieval times by 30%; improved Redis usage on Heroku for production stability; wrote end-to-end tests (Cypress) and unit tests (Jest).

Intermediate Software Engineer at WIX

December 1, 2021 - September 19, 2025

Refactored backend codebase using Django and GraphQL to fetch real-time data; migrated CI/CD pipelines from GitLab to Azure DevOps; managed AWS IAM and cloud infrastructure; implemented Daily Notifier from AWS CloudWatch and GA analytics; set up AWS Load Balancer and Auto Scaling for regional traffic; improved deployment and monitoring.

Intermediate Backend Engineer at PAYPAY

December 1, 2022 - September 19, 2025

Integrated PayPay card payment gateway; monitored production logs and data usage to optimize transaction estimates; redesigned 50+ CRUD endpoints; performed database migrations and backups; documented architecture and procedures; wrote ~30 tests with RSpec for key API flows.

Senior Software Engineer at BETCLOUD

January 1, 2023 - Present

Led development of flagship iGaming Casino and Sportsbook platform, delivering responsive, secure experiences across multiple themes. Built 120+ reusable components, designed RESTful APIs and real-time crypto data integrations, implemented WebSockets for odds and bets, and deployed with Docker and AWS to scale for peak events.

Junior Frontend Engineer at TRUFLATION

April 1, 2017 - October 4, 2025

Worked on frontend with React.js and Bootstrap 3, contributing to UI updates and performance analysis via Google Analytics and KPI sheets. Implemented 40+ user-friendly UI components, debugged issues with Chrome DevTools to improve FCP/LCP and SEO, and collaborated with backend to integrate third-party APIs for real-time data and features such as transaction pagination and chart displays.

Junior Software Engineer at TRUFLATION

December 1, 2019 - October 4, 2025

Collaborated with backend developers on Express/Node.js, MySQL, JWT, RESTful APIs, Sequelize, Redis, Postman, Cypress, Mocha, Docker, Kubernetes, PM2, and Heroku. Optimized data models and query builders, reduced data retrieval times by ~30%, improved Redis usage on Heroku to prevent production issues, and wrote end-to-end tests for critical data access and business logic layers.

Intermediate Software Engineer at WIX

December 1, 2021 - October 4, 2025

Refactored backend codebase with emphasis on Agile, SOLID/DRY principles, and modularization; migrated to GraphQL for real-time data display; reorganized a large codebase into component-based structure; transitioned CI/CD pipelines to Azure DevOps for maintainability and scalability; managed AWS IAM and automated access key rotation; implemented Daily Notifier via CloudWatch/GA for production growth and region-aware load balancing.

Intermediate Backend Engineer at PAYPAY

December 1, 2023 - October 4, 2025

Deliver & transfer backend integration for PayPay card payments. Monitored production logs to optimize estimated times and bonuses, managed database operations including migrations and backups, updated 20+ database structures, designed 50+ CRUD operations for new data models, and authored architecture and operational documentation. Primarily worked with Ruby on Rails and authored 30+ RSpec tests.

Senior Software Engineer at Heidi Health

January 1, 2024 - Present

Architected clinician-facing dashboards and backend services that merge React/TypeScript UIs with Node.js microservices. Implemented real-time transcription/summarization pipelines, GraphQL subscriptions, and WebSocket-based messaging for AI-generated notes. Automated infrastructure with Dockerized services on AWS ECS (Fargate), enhanced observability with CloudWatch and Prometheus, and collaborated with NLP teams to improve model accuracy. Optimized cost and scaling for healthcare-grade SLA compliance.