I'm a Ruby on Rails developer and full stack developer focused on SaaS and FinTech products. Day to day that's Ruby on Rails and React.js (Next.js, TypeScript) on PostgreSQL, deployed on AWS with Docker when the app needs it. 6+ years building production web applications — Top Rated Plus, 100% Job Success, 6,100+ Upwork hours, 85+ jobs. Most contracts run 1–4 years on one codebase. Available 30+ hours a week. Two years at SmartZip on their Rails + React lead-gen SaaS. Since then: B2B SaaS features, Stripe billing, GraphQL and REST APIs, Elasticsearch for search, Heroku-to-AWS migrations, Rails version upgrades. Frontend is React and Next.js; backend is Rails, Sidekiq, RSpec, and PostgreSQL done properly. I've also been adding AI features to live products — LLM API integration, chat interfaces and workflow automation. A long-term client, Olivier: "30+ eLearning apps, nearly 4 million plays — proactive, doesn't need hand-holding." Hiring a Ruby on Rails developer for ongoing SaaS work, full stack Rails + React, FinTech/Stripe, or a legacy app that needs a Rails upgrade or cloud migration? Send your repo or roadmap, I'll reply with an honest take on fit.

Name: Hien Nguyen Sex: Male Nationality: Vietnamese Years of Experience: - 7+ years of experience in programming with Ruby on Rails, Rspec, sidekiq, redis, AWS - 10 years of experience in programming with C#, ASP .NET languages. - Familiar with AWS, Google, Azure clouds, stripe, paypal payment platform.

I build AI-powered web applications and full-stack systems that are fast, scalable, and built to last. With 10+ years of experience, I work with founders, startups, and product teams to ship software that actually solves problems - from early MVPs to production-grade platforms. What makes me different: I combine deep full-stack engineering (Ruby on Rails, React.js, Node.js) with modern AI/ML capabilities (RAG pipelines, LLM integrations, AI agents) - so I can take your product from idea to a working, intelligent system. ━━━━━━━━━━━━━━━━━━━━━━━━━━ 🤖 AI & Automation ━━━━━━━━━━━━━━━━━━━━━━━━━━ ▪ RAG pipelines (LangChain, LlamaIndex, vector DBs) ▪ LLM integrations (OpenAI, Anthropic, Gemini) ▪ AI agents & workflow automation ▪ Chatbots, document Q&A, intelligent search ▪ n8n, Make, Zapier automation flows ━━━━━━━━━━━━━━━━━━━━━━━━━━ 💻 Full Stack Development ━━━━━━━━━━━━━━━━━━━━━━━━━━ ▪ Ruby on Rails (expert-level, 10+ years) ▪ React.js, Next.js, Node.js, Express ▪ PostgreSQL, MySQL, MongoDB ▪ REST APIs & third-party integrations ▪ SaaS platforms, dashboards, CRMs, marketplaces ━━━━━━━━━━━━━━━━━━━━━━━━━━ 🚀 What I bring to your project ━━━━━━━━━━━━━━━━━━━━━━━━━━ ▪ Led engineering teams & owned technical decisions ▪ Built and scaled SaaS products end-to-end ▪ Refactored legacy codebases into clean systems ▪ Clear communication + reliable delivery ▪ I treat your product like my own If you're building something ambitious - whether it's an AI-powered SaaS, a high-traffic web app, or an automation system - let's talk. 📩 Send me a message and you'll expect the reply promptly.

Looking for a Ruby on Rails expert who delivers reliable, high-performance web applications? With 9+ years of hands-on experience, I specialize in building scalable, secure, and business-driven web solutions. I don’t just write code—I focus on understanding your product vision and turning it into a robust application that delivers real value. Here’s What I Can Do for You: Ruby on Rails Mastery: I have deep expertise in Ruby on Rails, from clean and maintainable backend architecture to seamless frontend integration. I’m comfortable handling everything—from database design and API development to complex business logic and third-party integrations. Modern Tech Stack: I work with today’s most in-demand technologies, including PostgreSQL, Redis, Sidekiq, Hotwire (Turbo & Stimulus), React, REST & GraphQL APIs, and cloud platforms like AWS. I also have strong experience with Docker, background jobs, and service-oriented architectures. Technical Leadership & Architecture: I’ve led teams, reviewed system designs, and defined technical strategies aligned with best practices. I enjoy architecting applications that are scalable, secure, and easy to maintain as your product grows. Code Quality & Mentorship: Clean code matters. I actively follow best practices, write testable code, and conduct detailed code reviews. I also enjoy mentoring junior developers and improving overall team productivity and code standards. Performance & Scalability: I help applications run faster by optimizing database queries, implementing caching strategies, improving background processing, and identifying performance bottlenecks early. Security-Focused Development: Security is never an afterthought. I follow strong practices for authentication, authorization, data protection, and compliance, while staying updated with the latest security standards and vulnerabilities. CI/CD & DevOps Practices: I have hands-on experience setting up CI/CD pipelines, automated testing, and smooth deployment workflows to ensure faster releases and reliable production environments. Why Work With Me? Client-First Mindset: I believe in clear communication, transparency, and collaboration. I work closely with clients to understand their goals, deliver on time, and stay within budget. Always Learning, Always Improving: Technology evolves fast—and so do I. I continuously upgrade my skills to bring modern, efficient, and future-ready solutions to your projects. 🚀 Let’s build something great together. If you’re looking for a dependable Ruby on Rails expert who understands both technology and business, I’d love to work on your next idea.

As a dedicated Fullstack Developer specializing in Ruby on Rails and React (or Hotwire), I bring a wealth of experience and a commitment to excellence in every project I undertake. With a strong foundation in Ruby on Rails, JavaScript, Hotwire, and React, I have successfully contributed to numerous projects, consistently delivering high-quality solutions that align with clients' business objectives. Key Skills: - Proficient in Ruby on Rails, JavaScript, and React. - Experienced with Hotwire, Git, Docker, and RSpec. - Skilled in optimizing codebase for performance and security. Client Focus: I prioritize understanding my clients' needs and exceeding their expectations. Effective communication and close collaboration are integral to my development process, ensuring client satisfaction at every stage. Problem-Solving Approach: I thrive on solving complex challenges by leveraging analytical thinking and innovative solutions. Whether it's debugging live issues or optimizing code for performance, I approach each task with a problem-solving mindset. Quality Assurance: Dedicated to writing clean, maintainable code and conducting rigorous testing, I ensure the reliability and performance of all applications I develop. My commitment to quality set me apart in delivering robust solutions. If you're seeking a Fullstack Developer who combines technical expertise with a passion for innovation and excellence, look no further. I am ready to collaborate with you to bring your vision to life and make a positive impact through technology. #FullStackDeveloper #RubyOnRailsExpert #JavaScriptDeveloper #ReactSpecialist #HotwireDeveloper #SoftwareEngineering #CodeOptimization #ClientSatisfaction #QualityCode #ProjectCollaboration #PerformanceOptimization

Senior Ruby on Rails & React Developer | SaaS | APIs | AWS Hi, I'm Ronak, a Senior Full-Stack Developer with 10+ years of experience building SaaS platforms, marketplaces, business applications, and scalable web products. I specialize in Ruby on Rails, React, PostgreSQL, AWS, and API development. Over the years, I've helped startups and growing businesses build new products, scale existing applications, modernize legacy systems, and improve performance. I can help with: ✅ Ruby on Rails Development ✅ React.js Development ✅ REST API & GraphQL Development ✅ SaaS Product Development ✅ Marketplace Platforms ✅ Payment Gateway Integrations (Stripe, PayPal) ✅ Database Design & Optimization ✅ Performance Tuning ✅ Background Job Processing (Sidekiq, Redis) ✅ Rails Upgrades & Legacy Application Modernization ✅ AWS Deployment & Infrastructure ✅ Third-Party API Integrations Technical Expertise Backend: • Ruby • Ruby on Rails • PostgreSQL • MySQL • MongoDB • Redis • Sidekiq • REST APIs • GraphQL Frontend: • React.js • JavaScript • TypeScript • Vue.js • HTML5 • CSS3 • SASS • Bootstrap • Tailwind CSS Cloud & DevOps: • AWS • Heroku • Google Cloud Platform • Docker • CI/CD Pipelines Tools & Technologies: • GitHub • GitLab • Jira • Slack • Trello • Sentry • Honeybadger • New Relic • Rollbar • Elasticsearch Why clients choose to work with me: ✔ 10+ years of professional development experience ✔ Clean, maintainable, and scalable code ✔ Strong communication and reliability ✔ Fast onboarding into existing projects ✔ Experience working with startups and remote teams ✔ Focus on long-term solutions rather than quick fixes Whether you need a new application built from scratch, a Rails application upgraded, performance improvements, API integrations, or an experienced full-stack developer to join your team, I can help. Let's discuss your project and how I can contribute to its success.

I work on Ruby on Rails and Shopify-based systems, mainly focused on backend development, custom apps, and integrations. Most of the projects I handle involve connecting different systems, Shopify stores, APIs, third-party tools, and internal workflows. Recently, I’ve also been working on automation using n8n to reduce manual work and streamline processes. Here’s what I usually help with: - Ruby on Rails backend development and API creation - Shopify app development (custom features, private/public apps) - Shopify store improvements and custom functionality - Third-party integrations (payments, CRM, external APIs) - Workflow automation (webhooks, scheduled jobs, system sync) - Fixing or improving existing applications I try to keep things simple and reliable - clean backend logic, stable integrations, and solutions that are easy to maintain. If you already have a system and need improvements, integrations, or automation, I can review it and suggest a clear approach.

I help startups and growing businesses build and scale products and SaaS using Ruby on Rails. Over the past 4+ years, I’ve built and maintained production-grade applications across healthcare, e-commerce, POS, and SaaS platforms. My focus is backend architecture, Stripe billing systems, and API-driven applications that are built to scale. If you need a Rails developer who understands real business logic, subscriptions, payments, multi-tenant systems, background jobs, and performance optimization. I can help you ship fast and scale confidently. * Key Skills & Technologies: - Ruby on Rails | Hotwire | Turbo | Stimulus - PostgreSQL | Redis | Sidekiq | Active Record Optimizations - API Development & Integration (Stripe, Netsuite, TaxCloud, Twilio) - Front-end (Vue.js, React, Tailwind CSS, Bootstrap) - Authentication (Devise, JWT, OAuth, Omniauth) - Background Jobs & Performance Optimization - Cloud Deployment (GCP, AWS, DigitalOcean, Docker) - Agile Development | Git | CI/CD Pipelines * Why Work With Me? - Deep expertise in Rails with scalable architecture - Experienced in multi-tenant and billing systems (Stripe Connect) - Strong problem-solving mindset with a focus on performance - Effective communication & on-time project delivery Let's bring your idea to life with a powerful Ruby on Rails solution! Open to new projects, let’s discuss how I can help!

With over 13 years of experience and 14,000+ hours on Upwork, I create Ruby on Rails web applications that are not only functional but built to last. Able to take a project at any stage — from an initial idea to a complex, production-ready system — and manage every aspect: backend architecture, integrations, performance optimization, and long-term maintenance. I have successfully delivered large-scale projects across multiple domains — from a hotel booking engine to a fintech platform for investors, a job search and recruitment platform and many others. I leverage modern tools such as GitHub Copilot for documentation, autocomplete, code optimization, and SQL query improvements, while using AI assistants like ChatGPT and Gemini to speed up research and handle small tasks such as generating regular expressions. I also understand the importance of AI in boosting development speed, productivity, and automation, and apply it thoughtfully to enhance my workflow without compromising code quality. Whether you need to launch a new product, rescue a struggling codebase, or scale your existing platform, I bring the skills, reliability, and insight to get it done right the first time.

Experienced software developer specializing in online marketplaces and eCommerce applications. My daily responsibilities include developing and maintaining scalable web applications using Ruby on Rails and React.js, Linux server administration, scaling applications, managing databases, and optimizing application performance, reliability, and security. ### Languages & Frameworks * Ruby, Ruby on Rails, Sinatra * React.js, JavaScript, TypeScript, Next.js, Nest.js * Node.js, jQuery * Spree Commerce, Sharetribe Go * Bash Scripting ### Databases & Search Technologies * PostgreSQL, PostGIS, MySQL, Oracle * MongoDB, Cassandra, Neo4j, IndexedDB * Redis, Memcached, RabbitMQ * Apache Solr, Elasticsearch, Sphinx * Database normalization and performance optimization * Supabase * Prisma, Drizzle ORM ### API Development & Integrations * REST API development * Shopify API * Payment gateway integrations: Stripe, Authorize.Net, Braintree, Adyen, and others * Amazon Advertising & Marketplace APIs * Google APIs, Gmail API, Google Drive API, Adwords API * Facebook Ads API, Instagram API, YouTube API, Twitter API * USPS, FedEx, UPS APIs * Twilio API, Acuant API, Signifyd Fraud Detection API ### Frontend & UI Technologies * Bootstrap 3/4/5 * Tailwind CSS * ZURB Foundation, Materialize * HTML5, CSS3 * Responsive web and mobile design * Cross-browser testing for desktop, iPhone, and Android devices ### Data Visualization * AmCharts * FusionCharts * Highcharts * Plotly * Chart.js ### Cloud, DevOps & Infrastructure * AWS (EC2, S3, RDS, SES) * Docker, Heroku, DigitalOcean, Linode * Linux, Ubuntu, RedHat, Fedora * setting up FTP servers, cPanel * SSL certificate installation and server security ### Additional Experience * Maintaining and upgrading legacy Ruby on Rails applications * Claude / Cursor / code review workflows * Microservices architecture * Web scraping and automation * JWT authentication * MQTT and Kafka streaming * Automation tasks such as: - Facebook/Instagram/Google Ads publishing - Report generation - Backup automation ### Migration & Modernization * PHP/Laravel to Ruby on Rails migration * Django/Flask to Ruby on Rails migration * Node.js to Ruby on Rails migration ### Application Domains * eCommerce and marketplace platforms * Logistics and distribution systems * Chat applications * Real estate applications * SaaS applications