I am an ACM-ICPC World Finalist and software engineer. I have been developing backend and DevOps solutions using C++, Java, and Python since 2016. I have experience in multiple domains that include fintech, agrotech, health tech, IoT, and Saas. I have been working as a remote developer with globally distributed teams since 2019. I am a quick learner, good with communication, proactive and punctual human being. Nothing excites more me than a challenge that is necessary but difficult to solve.
I am also a competitive programmer and expert in data structures and algorithms. I have a decent understanding of UNIX systems especially how different types of data structures are blended to solve complex problems of operating systems.
I am a team player and can work as solo as well. I never compromise the quality of my work doesn't matter how the pressure is. And, I believe in requirement analysis as the most crucial part of engagement.
Python
Java
Linux
C++
C
Kubernetes
Docker
Git
Data Structures
Flask
Socket Programming
Multithreaded Programming
Django
Algorithm Development
Node.js
Prabin S.
Janakpur, Nepal
$12/hr
5.0
11 jobs
I’ve successfully completed multiple projects on Upwork with 5-star ratings and positive client feedback. If you’re facing any kind of tech-related problem, I’m here to help.
I specialize in backend development, frontend development, and database management. Over the years, I’ve built projects such as:
✅Enterprise Multi-Tenant SaaS POS Application
✅Expense Tracker
✅Food Delivery Web App
✅Smart Pharmacy Management System
✅Retail Billing Software
✅Trading Platform
✅Book Rental System
✅Hospital Management System
Previously, I worked as a Junior Backend Developer, where I created REST APIs, fixed bugs, collaborated with frontend developers, and managed databases. Working remotely strengthened my communication skills and taught me how to coordinate effectively with distributed teams.
Technical Skills
✅ Languages: Java, JavaScript, Python
✅ Frameworks: Spring Boot, Spring MVC, Hibernate, React, Tailwind CSS
✅ Web Services: RESTful APIs
✅ Databases: MySQL, PostgreSQL, MongoDB
✅ Tools: VS Code, IntelliJ, Eclipse, Postman, Git/GitHub
✅ Frontend: HTML5, CSS3, JavaScript
✅ Practices: Git-based version control, Agile methodology, automated testing
What I Can Do for You
✅ Develop and maintain RESTful APIs with Java & Spring Boot
✅ Design scalable and efficient backend architectures
✅ Build dynamic, responsive web interfaces with React, Tailwind CSS, HTML, and JavaScript
✅ Integrate relational databases and ensure data integrity
✅ Debug and fix performance or functional issues across the stack
✅ Collaborate with frontend, backend, and mobile teams for end-to-end solutions
✅ Deploy applications and assist with basic DevOps tasks
I believe in clear, friendly communication to keep projects running smoothly and ensure we’re always aligned.
Let’s chat about your project and see how I can help bring it to life!
“Any fool can write code that a computer can understand. Good programmers write code that humans can understand.” – Martin Fowler
Java
Spring Boot
Spring Framework
REST API
PostgreSQL
MySQL
NoSQL Database
JavaScript
React
Hibernate
Java Persistence API
Agile Software Development
AWS Lambda
Git
Web Development
Neella K.
Hyderabad, India
$55/hr
5.0
11 jobs
STRIPE CONNECT | STRIPE BILLING | STRIPE RADAR | STRIPE API | STRIPE CHECKOUT | STRIPE TERMINAL | FINTECH | SAAS | AI | PAYMENTS | COMPLIANCE (PCI DSS, GDPR)
If Stripe is slowing down your product, breaking your billing logic, or causing failed payments you can’t explain, I can fix that.
I’ve delivered 100+ Stripe integrations for SaaS and tech companies, and I’m a 4× Stripe Certified professional. You’re not getting a basic integration, you’re getting a payments system designed to reduce churn, recover revenue, and scale with your growth.
I specialize in building Stripe systems that directly impact metrics like churn, AOV (Average Order Value), LTV, and checkout conversion rates.
I don’t just plug APIs. I step into your architecture and make sure your billing, subscriptions, and payment flows are optimized end-to-end.
I can help if you’re dealing with:
🔹 High checkout abandonment rates
🔹 Unexpected churn from failed payments or poor retry logic
🔹 Broken or confusing subscription upgrades/downgrades
🔹 Low AOV due to poor pricing or payment flow design
🔹 Inconsistent or unreliable webhook handling
🔹 Stripe setups that “work” but don’t scale
What I can help you with:
🔹 End-to-end Stripe integration for SaaS platforms
🔹 Subscription architecture (plans, trials, proration, lifecycle logic)
🔹 Reducing churn with smarter retry logic and dunning strategies
🔹 Checkout optimization to improve conversion rates
🔹 Webhook architecture (reliable, scalable, no missed events)
🔹 Stripe account audits with revenue-focused insights
🔹 Advanced Stripe products (Connect, Sigma, custom workflows)
If you already have developers, I can work directly with them or guide them through the correct architecture in live sessions.
Most Stripe implementations leave money on the table. I help you close those gaps so your payments system actually drives revenue, not just processes it.
If you want to improve conversion, reduce churn, or fix hidden issues in your Stripe setup, send me a message and let’s take a look.
Python
Java
JavaScript
React
Next.js
WordPress
CMS Development
Node.js
API Development
AWS Development
OpenAI API
Payment Gateway Integration
Stripe
Stripe API
Stripe SDK
S.M. ATAUL KARIM R.
Dhaka, Bangladesh
$10/hr
4.8
70 jobs
I help startups, agencies, and businesses build secure, scalable, and high-performance web applications using modern technologies and AI-assisted development workflows.
With strong experience in backend engineering, API development, cloud infrastructure, and frontend frameworks, I deliver clean, maintainable solutions that are fast, reliable, and production-ready.
What I Can Help You With
✅ Custom Web Application Development
✅ REST API & GraphQL Development
✅ SaaS Platforms & Business Systems
✅ AI-Assisted Development & Automation
✅ Third-Party API Integrations
✅ Performance Optimization & Security Hardening
✅ Legacy System Upgrade & Modernization
✅ Cloud Deployment & DevOps Setup
Backend & Web Technologies
• Laravel, Django, Spring Boot, Yii2
• Express.js, NestJS
• WordPress, Drupal, Magento
• PHP, Python, Java, JavaScript, TypeScript
• MySQL, PostgreSQL, MongoDB, Redis
Frontend Development
• React.js, Vue.js
• Tailwind CSS, Bootstrap
• Alpine.js, Livewire, HTMX
Cloud & DevOps
• AWS, GCP
• Docker, Kubernetes
• CI/CD Pipelines
• Linux, Nginx, Apache
API & Integrations
• Stripe, PayPal
• Twilio, Firebase
• Slack, Zapier, Xero
• REST APIs & GraphQL
AI Development Workflow
I actively use modern AI development tools to improve delivery speed, code quality, debugging, and architecture planning:
• Cursor
• Claude
• ChatGPT
• GitHub Copilot
Why Clients Work With Me
✔ Clean, maintainable, scalable code
✔ Fast communication & reliable delivery
✔ Strong debugging and problem-solving skills
✔ Production-ready deployment experience
✔ Security-focused development approach
✔ Ability to work independently and take ownership
Whether you need a custom platform, backend API, cloud deployment, or ongoing development support, I can help turn your ideas into reliable software solutions.
Let’s build something great together.
Python
Java
MySQL
PHP
Laravel
Django
CakePHP
Yii
API Development
.htaccess File Creation
Ubuntu
Apache HTTP Server
Node.js
Spring Boot
Flask
Bohdan N.
Vinnitsa, Ukraine
$35/hr
5.0
20 jobs
⭐⭐⭐⭐⭐ Top Rated Plus on Upwork 100% Job Success Score
I'm a Java developer with 8+ years delivering production-grade systems from serverless AWS architectures to distributed microservices serving healthcare and fintech clients.
𝗪𝗵𝗮𝘁 𝗜'𝘃𝗲 𝗕𝘂𝗶𝗹𝘁
➡ As lead Java developer at my current company, managed a team of 8 engineers over 7 years — delivering 4 production systems across healthcare, fintech, and AI verticals.
➡ Designed serverless AWS infrastructure for a US longevity and healthcare platform as an AWS developer — Lambda, AppSync, DynamoDB, Cognito, SNS/SQS, Stripe, HubSpot currently in production.
➡ Led migration from monolithic Spring apps to distributed microservices — reducing deployment complexity and enabling independent scaling per service.
➡ Built a PDF/UA accessibility compliance platform as backend developer using Java 21, iText 7, PDFBox, veraPDF processing and remediating documents of hundreds of pages against international accessibility standards.
➡ Delivered an AI-powered workflow automation platform as an AI developer integrating Spring AI, Azure cloud, and automated Stripe subscription workflows.
➡ Shipped a medical practitioner dashboard integrating 3rd-party hardware APIs and clinical toolkits as backend developer and tech lead serving real patients and practitioners in production.
Core experience as a Java developer and Backend developer
As a Java developer with 8+ years in production systems, my core is Java 8 through Java 21 with the full Spring ecosystem Boot, Cloud, Security, WebFlux, Batch, and Spring AI for AI-integrated backends. I work across both relational (PostgreSQL, MySQL) and NoSQL (MongoDB, DynamoDB, Redis) databases, selecting the right store based on access patterns not habit.
As a backend developer I've optimised slow MongoDB queries to cut response times, redesigned DynamoDB access patterns for a high-throughput healthcare API, and built Redis caching layers that kept latency flat under load.
As an AWS developer, my hands-on stack covers Lambda, AppSync, DynamoDB, Cognito, SQS, SNS, SES, S3, API Gateway, Route 53, and CloudFormation built and maintained in a live US healthcare platform. I design serverless pipelines end-to-end, not just deploy to them. For async workloads I wire event-driven systems using Kafka, RabbitMQ, or AWS SNS/SQS depending on durability and throughput requirements. On the container side: Docker, Kubernetes, Helm, OpenShift, Terraform, and Jenkins full IaC from infrastructure definition to CI/CD pipeline.
As an AI developer, I've shipped Spring AI integrations for workflow automation backends, built document intelligence services capable of processing and remediating hundreds-of-pages PDFs against accessibility standards, and connected GraphQL APIs via AWS AppSync for mobile and web AI-driven applications.
I also have production experience integrating medical hardware APIs, Stripe subscription billing, and HubSpot CRM sync into Java backends the kind of third-party integration work every backend developer eventually owns in a real product.
AWS Developer & 𝗖𝗹𝗼𝘂𝗱 𝗘𝗻𝗴𝗶𝗻𝗲𝗲𝗿𝗶𝗻𝗴
✅ Currently operating as AWS developer on a live healthcare platform Lambda, AppSync, DynamoDB, Cognito, SQS/SNS/SES, S3, API Gateway, Route 53, CloudFormation
✅ Experience as AWS developer across serverless, containerized (ECS/K8s), and IaC (Terraform, CloudFormation) environments
✅ Also experienced across Azure (AKS, Azure DevOps) and GCP as multi-cloud backend developer
✅ Kubernetes, Helm, Docker, OpenShift, Jenkins, Terraform the full DevOps chain every AWS developer deploys through
AI developer 𝗖𝗮𝗽𝗮𝗯𝗶𝗹𝗶𝘁𝗶𝗲𝘀
✅ Delivered AI-powered backend services as AI developer using Spring AI automated content generation and workflow orchestration at scale
✅ AWS AppSync + DynamoDB + Cognito pipeline for a live healthcare platform: the architecture an AI developer builds when latency and data integrity are non-negotiable
✅ Experienced AI developer integrating third-party AI tooling with enterprise Java backends designing event-driven pipelines that handle async AI workloads via Kafka and SQS
✅ As AI developer, built document intelligence features automated PDF tagging, structure remediation, and accessibility validation across large document corpora
𝗜𝗻𝗱𝘂𝘀𝘁𝗿𝗶𝗲𝘀
Healthcare · Fintech · SaaS · E-commerce · Logistics · Telecom · IoT · Blockchain · Automotive · Media
𝗦𝗽𝗲𝗰𝗶𝗮𝗹𝗶𝘇𝗮𝘁𝗶𝗼𝗻𝘀 & 𝗥𝗼𝗹𝗲𝘀
✔ Senior Java Developer · Java Spring Boot Developer · Java Backend Developer
✔ AWS Cloud Engineer · AWS DevOps Engineer
✔ Azure Cloud Engineer · Google Cloud Engineer
✔ AI Backend Developer · Full-Stack Developer (Spring Boot + React)
✔ AI Backend Developer · Full-Stack Developer (Spring Boot + React)
Need a Java developer, backend developer, AWS developer, or AI developer who ships production systems — not prototypes? Drop me a message.
04/06/2026
Python
Java
SQL
Git
JavaScript
Node.js
MongoDB
Angular
MySQL
Software Development
Software Architecture & Design
Docker
Amazon Web Services
Spring Boot
DevOps
React
Artificial Intelligence
Machine Learning
Natural Language Processing
Desktop Application
Minh H.
Hanoi, Vietnam
$40/hr
4.9
29 jobs
Hi! I’m Minh Hoang - a Senior Full-Stack Engineer and Technical Lead with 7+ years of experience building and scaling SaaS products, with a strong focus on AI-powered applications.
I work with startups and founders to turn ideas into real, production-grade systems fast.
My edge is combining deep engineering expertise with AI-accelerated development workflows, allowing me to ship high-quality products significantly faster than traditional teams.
🚀 What I Do Best
💻 Full-Stack & AI-Enhanced Development
• Expert in React, Next.js, Node.js, TypeScript, Supabase
• Fast delivery using AI coding tools: Lovable, Cursor, Vibe Code, Replit, Base44, Code Augment
• Clean, modern architectures with excellent performance and maintainability
⚙️ Idea → Architecture → Production
I own products from first sketch to deployment, including:
• System design & architecture
• API development & data modeling
• Cloud infrastructure (AWS, Render, Vercel)
• CI/CD pipelines, testing, documentation
• Internal dashboards, design systems, and custom tooling
🧑💻 Solo Developer Delivery
• Frontend & backend development
• Infrastructure & DevOps
• AI integrations
• Admin panels, dashboards, automations
• Migrations, refactors, system upgrades
🧠 Domain Expertise
• AI & LLM Integrations
• Logistics & Optimization Tools
• Internal Management Tools
• Healthcare
• Real Estate
• E-Learning (LMS)
• Data Visualization
• OTT & Video Streaming
🌟 Project Highlights
• Delivered full SaaS platforms as lead or solo engineer
• Modernized legacy systems with modular architectures
• Converted 80+ pages of engineering logic into production software
• Built high-performance video player modules
• Created internal tools for automation and analytics
🛠️ Technical Strengths
• Languages: TypeScript, JavaScript, Go, Java, Python
• Frontend: React, Next.js, Vue.js, TailwindCSS, Material UI, Jquery
• Backend: Node.js, NestJS, Go, PostgreSQL, Supabase
• DevOps: AWS (S3, Amplify, KnowledgeBase, ...), Render, Vercel, Docker, GitLab CI/CD, Jenkins
• AI & Automation: n8n, OpenAI, LLM integrations, AI-driven tools
• Testing: Jest, Storybook, React Testing Library
• 3rd-Party Integrations: Garmin, Suunto, Oura, Apple Health, Google Health, Whoop, Xero, ...
• Payments & Billing: Stripe, PayPal, Lemon Squeezy
• AI Tool: Claude, Cursor, Codex, Antigrativy, Replit, Lovable
• Media/Streaming: HLS, DASH, VideoJS, Shaka
✨ Why Clients Work With Me
• Fast, clean, scalable engineering
• Clear communication & reliable delivery
• AI-accelerated development enables rapid iteration
• Strong focus on solving real business problems
💬 Let’s Build Something Great
If you need an MVP, SaaS product, internal dashboard, AI integration, or system overhaul, I can design it, build it, and ship it efficiently and professionally.
React
TypeScript
Node.js
Vue.js
PostgreSQL
MongoDB
Amazon Web Services
Jest
Docker
Material UI
Tailwind UI
Supabase
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