Senior Full-Stack Developer with 5+ years building production-grade Ruby on Rails and React/Next.js applications for clients in the US, Germany, Japan, and Pakistan. I specialize in AI-powered SaaS, multi-tenant architecture, Stripe payment integrations, and PostgreSQL-backed web applications — delivering clean, scalable code with zero back-and-forth. 🔧 WHAT I BUILD: • SaaS platforms (multi-tenant, role-based access, subscription billing) • AI-integrated web apps using Claude API, OpenAI, and LLM pipelines • Full-stack Next.js + Supabase + Stripe applications • Ruby on Rails APIs with Sidekiq, Action Cable, and RESTful design • Shopify custom apps, theme development & third-party integrations • React / Next.js frontends with Tailwind CSS & TypeScript • PostgreSQL query optimization, schema design & database migrations • CI/CD pipelines with Vercel, AWS, Docker, and GitHub Actions 💼 RECENT HIGHLIGHTS: • Co-founder & sole developer of ClearCare — an AI-powered B2B SaaS for US health insurance navigation (Next.js 14, Supabase, Stripe, Claude API) • Built and maintained full-stack features for Books4Memories (Germany), a memoir platform serving users across Europe • Developed server-driven UI pages at SubscribeHub (US) using Stimulus JS and Tailwind CSS wired to Rails backend • Built a Ruby on Rails PropTech platform with OpenAI-powered property valuation at Property Hub • Team Lead for 3+ junior Rails developers; ran Agile sprints and code reviews 🛠 TECH STACK: Ruby on Rails | Next.js 14 | React | TypeScript | JavaScript | Node.js | PostgreSQL | Supabase | Sidekiq | Redis | Stripe | Claude API | OpenAI | Tailwind CSS | AWS | Docker | Vercel | GitHub Actions | RESTful APIs | WebSockets | Action Cable | Shopify ✅ WHY CLIENTS CHOOSE ME: "Understands the vision without needing a lot of explanation" — "Goes out of his way to ensure the project is a success." 92% Job Success Score. Available 30+ hrs/week. Fast async communicator. Ready to build? Let's get started.

🏆 8+ Years Experience | Top Rated Plus | Full-Time Availability | Excellent Communication Greetings! I am a Computer Science Graduate and Full-Stack Developer with extensive experience in enterprise projects. I possess all the tools needed to bring your ideas to life. I prioritize close collaboration and communication with my clients, as this is your dream, and I'm here to build it. I am adept at working with other developers, whether as part of a team or independently, and can efficiently manage projects from start-up to completion. Frontend Skill Set: ✅ React.js / Next.js ✅ Vue.js / Nuxt.js ✅ TypeScript ✅ jQuery ✅ JavaScript ✅ Ant Design / Material-UI / Bulma / Bootstrap Mobile Development: ✅ React Native / Android / iOS Backend Skill Set: ✅ Node.js / Nest.js / Express.js ✅ Ruby on Rails ✅ Laravel ✅ Python (Django / Flask) AI Expertise: ✅ Generative AI, LLM, NLP ✅ Image Processing, Airflow, MLOPS ✅ Pandas, Scipy, Numpy, Matplotlib, Spacy, sklearn, scikit-image Specialized Technologies ($40/hr): ✅ OpenAI | ChatGPT ✅ Chatwoot | ChatBot Other Skills: Database Design and Architecture: MySQL, PSQL, SQLite3, MongoDB, Redis Git: Pull/Push, Branch Management, Merge, Rebase, Pull Request Agile Methodology API Concepts: GraphQL, REST API, SOAP APIs API Integration (Payment Gateways, Email Servers, SMS & IVR integration) API Development Hosting & App Deployment on Heroku, Amazon S3, Digital Ocean, and Private Servers UI/UX Suggestions Automation Test Cases Team Player & Team Management My response time is less than 30 minutes. I look forward to your messages. Thanks & Best Regards, Parmeet Singh Keywords: Full-Stack Developer | React Developer | Vue.js Developer | Mobile Developer | AI Specialist | OpenAI Expert | Chatbot Developer | API Integration | Database Architecture | Agile Methodology | Hosting & Deployment | Team Management | UI/UX Consultant | Automation Testing

⭐⭐⭐⭐⭐ "Great experience!!" Goal-oriented Fractional CTO with a demonstrated history in building SaaS products.

Building state-of-the-art, user-friendly websites is my passion. I take pride in crafting high-performance, intuitive web applications that meet modern industry standards. I am confident that my skills and experience make me an excellent choice for your projects. I stay ahead of the curve by continuously learning new technologies and keeping up with the latest industry trends. This proactive approach allows me to deliver exceptional solutions that not only meet but exceed client expectations. Let’s build something great together!

Currently, I am an independent software engineer. My Cat Feeding Tracker app demonstrates my ability to build user-facing features and implement RESTful integrations. I’m skilled in Ruby on Rails, Ruby, JavaScript, TypeScript, Node.js, Heroku/Render, TailwindCSS. Before transitioning into software development, I worked as a Global Process Engineer, where I led cross-functional raw material evaluation projects across distributed teams. In this role, I practiced product thinking—always focused on improving existing product performance and solving issues. I prioritized team success and long-term sustainability over individual achievements, consistently leveraging technology for problem-solving and data analysis.

I am Sr. Ruby on Rails developer. I have more than 9 years of experience as a full stack developer, a tech enthusiast, and expertise in Finance, E-commerce, Education, Food and AI. We have started working with AI as well and would like to assist client with our knowledge and experience. I help clients to build a web application from scratch to deployment and maintenance. I closely work with clients to understand their requirements and developed application that meets their expectations within time limits.

🚀 𝐓𝐨𝐩 𝐑𝐚𝐭𝐞𝐝 | ✅ 𝐒𝐡𝐨𝐩𝐢𝐟𝐲 𝐄𝐱𝐩𝐞𝐫𝐭 | ✅ 𝐑𝐮𝐛𝐲 𝐨𝐧 𝐑𝐚𝐢𝐥𝐬 𝐄𝐱𝐩𝐞𝐫𝐭 | 🕒 𝐀𝐯𝐚𝐢𝐥𝐚𝐛𝐥𝐞 𝐈𝐦𝐦𝐞𝐝𝐢𝐚𝐭𝐞𝐥𝐲 I’m an experienced Full-Stack Developer with 7 years of experience building scalable, high-performance web applications and conversion-focused e-commerce stores. I specialise in Ruby on Rails for robust back-end systems and Shopify for crafting powerful, revenue-driven online stores. Whether you need a custom web platform or a high-converting Shopify store, I bring a balance of clean code, modern design, and business-focused strategy to every project. Throughout my career, I’ve delivered a diverse range of solutions from scalable Ruby on Rails applications like healthcare platforms, CRMs, e-learning systems, and data dashboards to high-performing Shopify e-commerce stores. 💼 Services I Offer: 👉 𝐒𝐡𝐨𝐩𝐢𝐟𝐲 & 𝐒𝐡𝐨𝐩𝐢𝐟𝐲 𝐏𝐥𝐮𝐬 𝐃𝐞𝐯𝐞𝐥𝐨𝐩𝐦𝐞𝐧𝐭 🔹Custom Shopify theme development (Figma → pixel-perfect Shopify) 🔹Shopify Plus builds with advanced customization & scalability 🔹Conversion-focused UX/UI improvements 🔹Store setup, redesign, and feature enhancements 👉 𝐑𝐮𝐛𝐲 𝐨𝐧 𝐑𝐚𝐢𝐥𝐬 & 𝐂𝐮𝐬𝐭𝐨𝐦 𝐖𝐞𝐛 𝐀𝐩𝐩𝐥𝐢𝐜𝐚𝐭𝐢𝐨𝐧𝐬 🔹Scalable SaaS, CRM, dashboards, and custom platforms 🔹API development & third-party integrations 🔹Secure, maintainable, and high-performance backend systems 🔹Full-cycle development from MVP to enterprise-grade apps 👉 𝐌𝐢𝐠𝐫𝐚𝐭𝐢𝐨𝐧𝐬 & 𝐑𝐞𝐩𝐥𝐚𝐭𝐟𝐨𝐫𝐦𝐢𝐧𝐠 🔹Magento, WooCommerce, BigCommerce, OpenCart → Shopify or Rails 🔹Secure migration of products, customers, orders, and SEO data 🔹Rebuilding legacy systems into modern, scalable architectures 🔹Complex product logic, variants, and custom workflows 👉 𝐀𝐝𝐯𝐚𝐧𝐜𝐞𝐝 𝐂𝐮𝐬𝐭𝐨𝐦𝐢𝐳𝐚𝐭𝐢𝐨𝐧 & 𝐈𝐧𝐭𝐞𝐠𝐫𝐚𝐭𝐢𝐨𝐧𝐬 🔹Shopify: custom sections, metafields, and checkout logic (Plus) 🔹Rails: custom business logic, background jobs, API integrations 🔹ERP, CRM, payment gateways, and shipping integrations 🔹Automation workflows to streamline operations 🛒 Industries and Solutions Delivered: ➤ Fashion & Apparel ➤ Health, Wellness & Supplements ➤ Home, Living & Lifestyle ➤ B2B, Wholesale & Manufacturing ➤ SaaS Platforms, Marketplaces & Data Dashboards 🔧 Tools & Technologies: 🛒𝐄-𝐜𝐨𝐦𝐦𝐞𝐫𝐜𝐞 & 𝐒𝐡𝐨𝐩𝐢𝐟𝐲 - Shopify, Shopify Plus, Liquid, JavaScript, HTML/CSS - Klaviyo, GA4, Stripe, PayPal, Razorpay ⚙️ 𝐅𝐮𝐥𝐥-𝐒𝐭𝐚𝐜𝐤 𝐃𝐞𝐯𝐞𝐥𝐨𝐩𝐦𝐞𝐧𝐭 - Ruby on Rails, Node.js, Express.js - React.js, Next.js, Redux, Vue.js - JavaScript (ES6+), TypeScript 🗄️ 𝐃𝐚𝐭𝐚𝐛𝐚𝐬𝐞𝐬 & 𝐀𝐏𝐈𝐬 - MongoDB, PostgreSQL, MySQL - REST APIs, GraphQL, Firebase 🎨𝐅𝐫𝐨𝐧𝐭𝐞𝐧𝐝 & 𝐔𝐈 - Tailwind CSS, SCSS, SASS, Bootstrap, GSAP - Figma (pixel-perfect implementation) ☁️ 𝐂𝐥𝐨𝐮𝐝 & 𝐃𝐞𝐯𝐎𝐩𝐬 - AWS, Azure, GCP, RunPod 🤖𝐀𝐈 & 𝐀𝐮𝐭𝐨𝐦𝐚𝐭𝐢𝐨𝐧 - ChatGPT integrations, AI-powered workflows 💡 What Sets Me Apart: ✔ Strong blend of Shopify e-commerce + Ruby on Rails engineering ✔ Focus on business results, not just development ✔ Clean, scalable, and future-proof code ✔ Proven ability to handle complex, high-growth projects 🚨𝐈𝐟 𝐲𝐨𝐮'𝐫𝐞 𝐥𝐨𝐨𝐤𝐢𝐧𝐠 𝐟𝐨𝐫 𝐚 𝐟𝐮𝐥𝐥-𝐬𝐭𝐚𝐜𝐤 𝐞𝐱𝐩𝐞𝐫𝐭 𝐰𝐡𝐨 𝐜𝐚𝐧 𝐛𝐮𝐢𝐥𝐝 𝐜𝐨𝐦𝐩𝐥𝐞𝐱 𝐚𝐩𝐩𝐬, 𝐬𝐜𝐚𝐥𝐞 𝐢𝐧𝐟𝐫𝐚𝐬𝐭𝐫𝐮𝐜𝐭𝐮𝐫𝐞, 𝐚𝐧𝐝 𝐝𝐞𝐥𝐢𝐯𝐞𝐫 𝐩𝐨𝐥𝐢𝐬𝐡𝐞𝐝 𝐔𝐈𝐬, 𝐈'𝐦 𝐡𝐞𝐫𝐞 𝐭𝐨 𝐛𝐫𝐢𝐧𝐠 𝐲𝐨𝐮𝐫 𝐯𝐢𝐬𝐢𝐨𝐧 𝐭𝐨 𝐥𝐢𝐟𝐞. 𝐖𝐡𝐞𝐭𝐡𝐞𝐫 𝐢𝐭'𝐬 𝐒𝐡𝐨𝐩𝐢𝐟𝐲, 𝐑𝐚𝐢𝐥𝐬, 𝐨𝐫 𝐑𝐞𝐚𝐜𝐭, 𝐈’𝐥𝐥 𝐡𝐞𝐥𝐩 𝐲𝐨𝐮 𝐬𝐡𝐢𝐩 𝐟𝐚𝐬𝐭 𝐚𝐧𝐝 𝐬𝐦𝐚𝐫𝐭!

⭐️ Top Rated Plus - Top 1% of talent on Upwork ✅ 10+ Years of Experience ✅ Developed MVPs to Enterprise Level Products ✅ Worked with Cross Functional Teams I'm a Senior Full-Stack Developer with over 10 years of experience. I specialize in developing SaaS Applications, Fintech Applications, ERP Systems, IoT Applications, and E-commerce Platforms. My expertise covers everything from designing software architecture and databases to building web applications. My track record speaks volumes—I've spearheaded the development of numerous successful projects, blending technical expertise with strategic insight every step of the way. 𝐇𝐞𝐫𝐞'𝐬 𝐚 𝐆𝐥𝐢𝐦𝐩𝐬𝐞 𝐈𝐧𝐭𝐨 𝐌𝐲 𝐂𝐨𝐫𝐞 𝐄𝐱𝐩𝐞𝐫𝐭𝐢𝐬𝐞: - Languages: Ruby, JavaScript, TypeScript - Frontend: React, Redux, StimulusJS, Next.js, Vue.js, Angular.js, Ember.js, Backbone.js, Material UI, Bootstrap, jQuery, Ajax, Hotwire, TurboFrame, Tailwind CSS, HTML5, CSS3 - Backend: Ruby on Rails, Sinatra, Hanami, Node.js, Express.js, Nest.js - APIs: RESTful API, GraphQL, GrapeAPI, Fast JSON API, Rails Serializers, 3rd Party API Integration 𝐀𝐝𝐝𝐢𝐭𝐢𝐨𝐧𝐚𝐥 𝐏𝐫𝐨𝐟𝐢𝐜𝐢𝐞𝐧𝐜𝐢𝐞𝐬: - Databases: MySQL, PostgreSQL, MongoDB, Firebase, Elastic Search, Redis, Dynamo DB - Cloud Computing: AWS, Azure, Heroku, DigitalOcean, Amazon EC2/EBS. - Payment Gateways: Stripe, PayPal, Braintree, Authorize.net. - CI/CD: Circle CI, Travis CI, Bitrise - CMSs: Contentful, Netlify, ExpressionEngine, Prismic, GraphCMS, Cosmic, WordPress, Shopify, Joomla 𝐍𝐨𝐰, 𝐥𝐞𝐭'𝐬 𝐭𝐚𝐥𝐤 𝐠𝐞𝐦𝐬. 𝐅𝐨𝐥𝐥𝐨𝐰𝐢𝐧𝐠 𝐠𝐞𝐦𝐬 𝐭𝐡𝐚𝐭 𝐈 𝐮𝐬𝐞𝐝 𝐦𝐨𝐫𝐞 𝐞𝐱𝐭𝐞𝐧𝐬𝐢𝐯𝐞𝐥𝐲 𝐢𝐧 𝐚𝐩𝐩𝐥𝐢𝐜𝐚𝐭𝐢𝐨𝐧𝐬: - Devise, OmniAuth, CanCan, Will_paginate, Paperclip, Simple_form, Pry, Haml/Slim. - ElasticSearch, Thinking Sphinx, Sunspot, Finance. - Delayed_job, Sidekiq, Rescue, EventMachine, Capistrano, Chef. - RSpec, FactoryGirl, Shoulda, Capybara, Selenium. 𝐓𝐡𝐞 𝐬𝐨𝐟𝐭𝐰𝐚𝐫𝐞 𝐝𝐞𝐯𝐞𝐥𝐨𝐩𝐦𝐞𝐧𝐭 𝐜𝐲𝐜𝐥𝐞 𝐚𝐧𝐝 𝐛𝐮𝐠-𝐭𝐫𝐚𝐜𝐤𝐢𝐧𝐠 𝐭𝐨𝐨𝐥𝐬 𝐭𝐡𝐚𝐭 𝐈'𝐦 𝐮𝐬𝐞𝐝 𝐭𝐨 𝐚𝐫𝐞 𝐚𝐬 𝐟𝐨𝐥𝐥𝐨𝐰𝐬: - Agile Process (Scrum methodology) - Git/SVN - JIRA, Pivotal Tracker, Basecamp, Trello, Harvest, Hubstaff - Slack, Hangouts, Skype Whether you're a startup looking to kickstart your MVP, an enterprise in need of custom solutions, or a business aiming to optimize your existing application, count on me to be your go-to collaborator. Together, let's turn your ideas into reality and propel your business forward. You can find me with these buzzwords: Agile Development Analytics And Reporting API Integration B2B Marketplace B2C Marketplace Booking Marketplace Client Communication Cross-Platform Compatibility Custom E-Commerce Solutions Digital Marketplace E-Commerce Platform E-Commerce Solutions E-commerce Website Development Back-end Developer Back-End Development Back-End Web Developer Back-End Engineer Back-end Ruby Back-end Web Developer Marketplace App Development Marketplace Consultant Marketplace Custom Features Marketplace Customization Marketplace Developer Marketplace Engagement Marketplace Expert Marketplace Features Marketplace Flex Marketplace Go Marketplace Growth Marketplace Hosting Marketplace Integration Marketplace Launch Marketplace Management Marketplace Marketing Marketplace Mobile App Marketplace Monetization Marketplace Optimization Marketplace Platform Marketplace Revenue Models Marketplace Scalability Marketplace Security Marketplace SEO Marketplace Software Marketplace Strategy Marketplace Support Marketplace Testing Marketplace UX/UI Design Marketplace Website Development Monetization Strategies Multi-Vendor Marketplace New Sharetribe Onboarding Processes Online Marketplace Development Online Store Development Payment Gateway Integration Peer-To-Peer Marketplace Performance Optimization Problem-Solving Skills Project Management Quality Assurance Ruby Developer Ruby on Rails Ruby on Rails Developer Ruby Back-end Developer Rental Marketplace Responsive Design SaaS Security Implementation Service Marketplace Sharetribe Customization Sharetribe Developer Sharetribe Expert Sharetribe Flex Sharetribe Go Sharetribe Marketplace Subscription Marketplace Technical Expertise Vendor Management Website Website Builder Website Developer Website Development Web App Developer Web Developer Web Developer Back- End Web Developer Ruby on Rails Coder

🟢 Available Now! 🏆 I'm a Top-Rated full-stack developer with 12 years of experience, proficient in a diverse array of technologies, frameworks and AI Workflow automation. 🔥 Also, I would like to join any RUST-involved project as middle developer and minimal rate of $10/hr (I need commercial Rust experience). Currently I'm specializing in Ruby on Rails/Ruby, Python/FastAPI/Flask, JavaScript/TypeScript, Datastar/htmx/stimulus (hypermedia), React/Vue.js, Next.js/Nuxt.js, PostgreSQL, containers and n8n workflows. Proven track record in building and scaling complex web applications using best practices. Strong background in CI/CD, infrastructure management/automation, and cloud deployments. Available for full-time or contract roles. ⚠️️ Choose my specialization in menu and find out more 💼 Over 4000 work hours logged on Upwork and a long list of happy long-term clients. --- 🤝 INDUSTRIES SERVED LONG-TERM - High-load IoT company (realtime microservices) - Healthcare company (medical cards storing and processing) - Virtual mobile operator (realtime microservices) - Logistics company - Car sell service (parsing car sale listings) - Music application backend - Tens of corporate websites (web design, implementation) using various stacks --- 👨‍💻 LANGUAGES - Daily: Ruby, Python, Rust, TypeScript, PL/pgSQL, *sh - Exotic: Elm (underrated gem), Clojure, Haskell, Lua 🐍 PYTHON Frameworks: - FastAPI - FastHTML - Flask Main libs: - asyncpg, AlchemySQL (Core/ORM) - imageio/Moviepy - most likely anything else you'll throw at me 💎 RUBY Web frameworks: - Rack - Sinatra - Hanami - Grape - Ruby on Rails + Hotwired Main libs: - Warden, Pandit, Devise - DRY-* family - PG+query objects, Sequel, ROM, Arel - PORO (Plain Old Ruby Object) - i.e. anything low-level/lightweight ⚡ JAVASCRIPT/TYPESCRIPT Frameworks in order of preference: - Datastar/htmx (hypermedia) - React/Next.js - Vue.js/Nuxt.js - SvelteK/SvelteKit Main libs: - Drizzle ORM - Polka - Express.js - Auth.js - TypeSpec --- 🗄️ DBs/EVENTS - PostgreSQL (favorite!), Elasticsearch, Redis, MySQL, MongoDB, ClickHouse (noob) - Nats.io - just perfect! 🧩 APIs/SERVICES INTEGRATION - OpenAI (ChatGPT), Twilio/Sendgrid, Stripe, Braintree, Pay.nl, Onomondo, tens of them, actually, I can integrate everything - AWS, Azure, GCP, DigitalOcean - Slack, NewRelic, Jenkins - ...tens of them 🐳 DEVOPS - Hashicorp stack (Nomad, Consul, Vault) - my choice if k8n is overkill for the task - Terraform (just love it!) - Ansible (advanced multi-env configurations) - Grafana, Loki, Prometheus - Docker, Ansible, Packer, Capistrano (but prefer ansistrano), etc. 🛠️ SOFTWARE INSTALLATION - n8n (single/cluster mode) - docker - OpenProject - wireguard (VPN) - CloudFlare tunnels (Zero Trust) - ...lots/any of them ☁️ CLOUDS - Google Cloud Platform (almost everything but ML and BigData tools) - AWS - including autoscaling and load balancers of all types - Heroku - DigitalOcean - Render.com, Railway, Heroku, Vercel, Render.com, Neon, Fly.io - literally any --- ⌛ Available 7 days a week, up to 10 hours a day, at any time you need.

As a Full-stack developer, my focus on full stack development has been sharpened by working with a diverse array of clients and technologies, including Ruby on Rails, ASP.NET , React, Vue.js and GraphQL. My tenure has been marked by creating robust web applications and leading innovative projects that drive client satisfaction and operational efficiency. With over seven years of service and a recognized status as top-rated plus on Upwork, has honed my skills in delivering high-quality software solutions. Collaborating closely with teams, I've contributed to the development of applications that meet rigorous standards, leveraging my expertise to strengthen the technical foundations and foster success for our clients and organization.