06/04/2026 updated
100 % available
Senior Full Stack Developer
Chuo, Japan
Only remote
Computer Science Bachelor's degreeAbout me
⭐️ Have a cup of coffee and chat with me.⭐️ ⭐️ Strict confidentiality guaranteed, in full compliance with Non-Disclosure Agreements (NDAs) ⭐️
AI AgentsSupabaseFlutterPHPAndroid (Software)IOS ApplicationsAutomationPython (Programming Language)LaravelNode.jsAngular 2+Next.jsTypeScriptReact.jsGoogle Firebase
Full Stack Web Development
Expertise in building scalable, secure web applications across the full stack using React, Next.js, Angular, TypeScript, Node.js, Nest.js, C#/.NET, and Python, covering both frontend architecture and backend business logic.
RESTful API Design and Integration
Design and implementation of RESTful APIs connecting internal and external systems, including payment gateways, WhatsApp platforms, authentication systems, CRM tools, and other third-party business services.
Database Design and Optimization
Strong experience with relational and non-relational databases including PostgreSQL, SQL Server, MongoDB, Supabase, and Firebase, covering database design, query optimization, performance tuning, and data modeling.
AI Chatbot and Automation Development
Development of AI-powered chatbot systems and automation workflows for customer support, lead management, and business process automation, including conversational flow implementation and WhatsApp integration.
Blockchain Application Development
Building blockchain-enabled web applications and integrating blockchain-based solutions into scalable platforms.
CI/CD and DevOps Support
Support for CI/CD pipelines, release management, deployment workflows, and production monitoring to ensure stable and reliable software delivery.
Security and Access Control
Implementation of authentication, role-based access control, secure coding practices, and API security across web platforms.
Application Performance and Architecture
Scalable application architecture design, system design, application performance optimization, reliability improvement, and maintainable code structure.
Testing and Production Support
Unit testing, integration testing, bug fixing, troubleshooting, production support, and post-launch maintenance to ensure stable platform operations.
Cloud Infrastructure and Monitoring
Management of cloud infrastructure across DigitalOcean, Upstash, and Google services, with monitoring and analytics tooling using Grafana, Sentry, and GA4.
Expertise in building scalable, secure web applications across the full stack using React, Next.js, Angular, TypeScript, Node.js, Nest.js, C#/.NET, and Python, covering both frontend architecture and backend business logic.
RESTful API Design and Integration
Design and implementation of RESTful APIs connecting internal and external systems, including payment gateways, WhatsApp platforms, authentication systems, CRM tools, and other third-party business services.
Database Design and Optimization
Strong experience with relational and non-relational databases including PostgreSQL, SQL Server, MongoDB, Supabase, and Firebase, covering database design, query optimization, performance tuning, and data modeling.
AI Chatbot and Automation Development
Development of AI-powered chatbot systems and automation workflows for customer support, lead management, and business process automation, including conversational flow implementation and WhatsApp integration.
Blockchain Application Development
Building blockchain-enabled web applications and integrating blockchain-based solutions into scalable platforms.
CI/CD and DevOps Support
Support for CI/CD pipelines, release management, deployment workflows, and production monitoring to ensure stable and reliable software delivery.
Security and Access Control
Implementation of authentication, role-based access control, secure coding practices, and API security across web platforms.
Application Performance and Architecture
Scalable application architecture design, system design, application performance optimization, reliability improvement, and maintainable code structure.
Testing and Production Support
Unit testing, integration testing, bug fixing, troubleshooting, production support, and post-launch maintenance to ensure stable platform operations.
Cloud Infrastructure and Monitoring
Management of cloud infrastructure across DigitalOcean, Upstash, and Google services, with monitoring and analytics tooling using Grafana, Sentry, and GA4.
Experience
Professional experience5 - 10 years
Freelancer since2018
Languages
EnglishGood
Project history
Delivered end-to-end solutions for SaaS platforms, blockchain applications, AI chatbot systems, and custom web applications. Designed and developed scalable frontend and backend features, built and integrated RESTful APIs, developed chatbot and automation solutions, and collaborated directly with clients to deliver reliable products aligned with business goals.
Independently designed, developed, and launched Advmastersia end-to-end, owning the full lifecycle from architecture and backend implementation to frontend delivery, deployment, and post-launch support. Built the platform with Next.js and Supabase, integrated third-party services including Evolution API, Google Calendar, Microsoft Calendar, and ChatGPT, and managed cloud infrastructure across DigitalOcean, Upstash, and Google services.
Developed and maintained a SaaS platform delivering scalable and reliable web application features across frontend and backend. Built chatbot systems and WhatsApp automation workflows, integrated payment gateways and third-party APIs, designed and consumed RESTful APIs, and collaborated with cross-functional teams to support ongoing product growth.