Hire the Best Backend Rest API Freelancers
in Vietnam

🚀 I help eCommerce businesses grow sales, improve performance, and simplify operations through high-quality Magento 2, WordPress, and WooCommerce development. With 10+ years of experience building and optimizing online stores, I specialize in: Magento 2 Development & Custom Modules – payment integrations, API connections, custom features, and backend logic. WooCommerce & WordPress – theme customization, plugin development, speed optimization, and SEO improvements. eCommerce Performance Optimization – faster load times, smoother checkout, and higher conversion rates. Shopify Customization – theme tweaks, custom apps, and store setup. Why work with me? ✅ Top Rated Plus on Upwork with 100% Job Success – trusted by clients worldwide. ✅ Clear, proactive communication – you’ll never be left guessing about progress. ✅ Strong problem-solving skills – I don’t just code; I help you find the best technical solution for your business goals. ✅ Long-term reliability – many of my clients return for ongoing support and future projects. Recent Wins: Boosted a Magento store’s loading speed by 40%, increasing conversions by 25%. Integrated a custom payment module for a membership-based store. Built an API connector to sync orders between Magento and a third-party logistics system in real time. If you’re looking for a skilled eCommerce developer who can deliver fast, secure, and scalable solutions, let’s talk. I’m here to make sure your store not only works — but works better than you imagined. 💬 Send me a message and let’s discuss your project today.

Dear, I'm a full-stack developer specializing in WordPress, WooCommerce, and modern JavaScript, with 10+ years of experience and 100+ completed Upwork projects. How I can help: E-commerce — Build and scale WooCommerce stores that convert. Speed & SEO — Faster load times, better Core Web Vitals, higher rankings. Custom Dev — Bespoke themes, plugins, and REST API integrations. Fixes & Migration — Bug fixes, safe migrations, and ongoing support. Tech stack: PHP, JavaScript, .NET (C#), Python, React, MySQL, REST APIs. I also use AI tools to work faster and smarter — meaning quicker turnaround and better value, without compromising quality. Reliable delivery, clear communication, and a focus on your business goals. Let's build something great — send me a message.

Backend Engineer with 5+ years of experience building production systems with NestJS, TypeScript, PostgreSQL, Kafka, Django, React, and Next.js. I help product teams design reliable APIs, event-driven services, payment flows, AI-enabled features, and backend-first full-stack products. At Restaff, I build healthcare services with NestJS, Kafka, PostgreSQL, and Grafana. Previously at Immersio, I scaled a multi-tenant EdTech platform across a NestJS/Django backend and Next.js frontend, built Stripe and PayPal subscription infrastructure, and shipped LLM-powered features that reduced content preparation time by 80%. What I can deliver: • NestJS APIs and microservices • PostgreSQL schema design and query optimization • Kafka workflows and service integrations • Authentication, subscriptions, and payment integrations • Backend-first features with React and Next.js • Production debugging, observability, and refactoring • LLM feature integration Core stack: NestJS, TypeScript, Node.js, PostgreSQL, Kafka, Redis, RabbitMQ, Django, React, Next.js, Docker, Grafana, Stripe, and PayPal. I can own a feature from architecture and implementation through testing and production rollout.

Help startups and indie hackers build secure, reliable, and scalable software, allowing founders to focus on business growth without worrying about technical limitations or system failures. Some of my past projects: - Invygo: a car subscription platform operating in the UAE and Saudi Arabia, serving over 20,000 long-term paying subscribers (from 1 yr), more than 100,000 total subscribers, and managing over 5,000 vehicles. - Ayyeka: a global IoT platform for critical data management, processing more than 3 million data points per hour across the US, Europe, MENA, and Asia. How can I help: - Design or improve scalable and reliable software architectures. - Do improvements for security and compliance requirements. - Build production-ready MVPs. - Build reliable and measurable AI solutions using LLMs, RAG, and agents. Also much experience for fixing hallucinations in AI systems. - Lead cross-functional teams and technical projects to achieve business goals. - Mentor junior engineers. I offer a free 15-minute consultation. Feel free to schedule a call to discuss your product or technical challenges. Keywords: - Backend: Node, Python, NestJS, Hono, Go, GraphQL, REST, tRPC, WebSocket, SSE, WebRTC, etc - Frontend: React, Next, Angular, Vue, TypeScript, Tailwind. - Mobile: React Native, Expo, iOS, Android, BLE. - Data: PostgreSQL, MongoDB, Redis, Supabase, Prisma, Drizzle. - Cloud: AWS, GCP, Cloudflare, Docker, Kubernetes, Terraform, CI/CD. - AI: Generative AI, Agentic AI, Automation, RAG, LangGraph / LangChain, Mastra, Vercel AI SDK, Composio, Embeddings, Vector DBs. - Payments: Stripe, PayPal, RevenueCat, Paddle, Polar, Checkout.

Hi, I'm Jack (Tran Van Diep). I help businesses build AI-powered systems, intelligent agents, and scalable software products that automate operations, reduce costs, and accelerate growth. Although I am new to Upwork, I am not new to software development. I bring over 15 years of hands-on experience building mobile applications, backend systems, SaaS platforms, and enterprise solutions. Today, my primary focus is helping startups and businesses adopt AI through Agentic AI, workflow automation, and custom AI-powered applications. I am also the founder of a software development company in Vietnam, where I have led engineering teams, delivered production systems, and helped clients transform business ideas into successful digital products. I joined Upwork to build long-term relationships with international clients and expand my AI and software development services globally. 🚀 AI Agents & Agentic AI (Primary Focus) I design and build intelligent AI systems that can reason, make decisions, interact with tools, and automate business workflows. • AI Agents & Multi-Agent Systems • Agentic AI Applications • LangChain & LangGraph • Retrieval-Augmented Generation (RAG) • Knowledge Base AI Assistants • AI Customer Support Systems • Workflow Automation & AI Orchestration • Claude, ChatGPT, Gemini & Open-Source LLM Integrations • Internal Enterprise AI Assistants • AI-Powered SaaS Platforms ✔ Mobile Development • Android (Java, Kotlin, Jetpack Compose) • iOS (Swift, SwiftUI) • Flutter & React Native ✔ Backend & System Architecture • Scalable Microservices Architecture • REST APIs & Platform Development • Event-Driven Systems • Real-Time Communication Platforms • WebSocket Infrastructure • Cloud-Native Applications • Database Design & Optimization What I bring to your project: • 15+ years of professional software development experience • Strong AI implementation and system architecture expertise • Ability to transform business processes into AI-driven workflows • Clean, maintainable, production-ready code • Experience leading engineering teams and delivering complex products • Clear communication and transparent collaboration • A long-term technology partner mindset Projects I can help you build: • AI Agents for Business Automation • AI Customer Support & Knowledge Assistants • AI Workflow Automation Platforms • Internal Company AI Tools • AI-Powered SaaS Products • Real-Time Communication Platforms • Mobile Applications • Enterprise Systems • Custom Software Solutions I understand that trust is important when hiring a freelancer, especially someone who is new to Upwork. That is why I focus on delivering measurable business outcomes, maintaining clear communication, and building long-term partnerships with every client. If you are looking for a developer who can contribute not only as an engineer but also as an AI solutions architect and technical partner, I would be happy to discuss your project. Let's build intelligent systems that create real business value.

I am a full-stack Ruby on Rails developer with years of experience and a degree in computer science. I appreciate clean, beautiful codes & clear communication. I am experienced with building, maintaining, and scaling web projects using Ruby on Rails. I have done everything from the most basic CSS to setting up production servers. I have been exposed to different industries using various processes and technologies. I'm also a skilled and passionate Shopify developer with more than 6 years of experience in crafting exceptional and seamless e-commerce solutions. My journey into the world of web development started with a love for creativity and problem-solving, which eventually led me to specialize in Shopify development. SKILLS and KNOWLEDGE: # Web Development - Expertise in developing, profiling, and debugging with Rails and Ruby - Experience in designing REST-APIs and profiling Rails applications. - Engineering experience with building scalable MVC, event-based, modular, API-driven software. - Experience in CMS gems (Refinery, ComfortableMexicanSofa), - Strong knowledge of HTTP, REST, Redis, PostgreSQL, MySQL, MongoDB - In-depth knowledge and practice in TDD with Rspec, Cucumber. - Strong knowledge about popular gems such as Devise, Cancancan, Rolify, Paperclip, Trailblazer, etc... - Working knowledge of Capistrano, Mina, Git. - Front end HTML, JS, CSS ability. - Familiar with ReactJS, VueJS, Jquery, CoffeeScript, AngularJS, BackboneJS, ExtJS, Twitter Bootstrap, Foundation. - Experience in using/setting up continuous Integration tools such as Codeship, Jenkins, Tddium. - Working knowledge in Google API, Facebook API, Stripe API, Paypal API. - Web administration experience in Linux/Windows base servers. SSH, Cpanel, Amazon Web Service - Working experience in Agile environment. - Cloud experience​ in Amazon, Engie Yard, Digital Ocean. # Shopify skills: - Shopify Expertise: In-depth knowledge of Shopify's platform and features. - Custom Theme Development: Crafting captivating and unique online store designs. - Shopify App Development: build apps to add advanced features to stores. - Liquid Templating: Creating dynamic and personalized content for an engaging user experience. - App Integration: Seamlessly integrating third-party apps to extend functionality. - E-commerce Optimization: Enhancing store performance and conversion rates. - Responsive Design: Ensuring a flawless shopping experience across all devices. - API Proficiency: Leveraging APIs for seamless data exchange and functionality. - Problem-Solving: Analyzing challenges and providing innovative solutions.