I help startups, SMEs, and enterprise clients design, build, and scale complex business platforms — from fintech and payments to inventory, invoicing, memberships, and AI-powered automation. With 18+ years of experience in mission-critical systems (Payments, Fintech, POS, remittance, IoT, AI), I lead agile teams to deliver robust, scalable, and secure solutions across cloud and on-premise environments. Core Solutions I Deliver: Payments & Remittance Systems End-to-end payment gateways (APIs, processors, PCI-DSS infra) Mobile-first remittance apps (KYC/AML, Pay-in / Payout / FX, Admin, Compliance) White-labeled payment gateway platforms for ISOs, fintechs, and merchants Inventory Management Platforms Multi-channel inventory sync (web, mobile, POS) Distributor ↔ Retailer integrations Predictive reordering, shelf optimization, low-stock alerts Invoicing & Billing Systems Recurring billing, membership management, revenue recognition Integration with QuickBooks, Sage, and ERPs Payment, refund, chargeback workflows AI-Powered Automation Generative AI platforms (content generation, document automation) Workflow automation to cut costs and increase speed-to-market IoT Cloud Solutions Remote firmware update platforms (OTA, rollback strategies) Device management, campaign control, analytics dashboards Membership & Subscription Platforms Subscription billing, renewals, discount engines, dashboards Secure payment flows, reporting, analytics How I Work: End-to-End Delivery (Architecture, Development, QA, DevOps) Scalable, Compliant, Secure Systems Collaborative & Transparent Project Management Recent Success Stories: RetailTech SaaS: Scaled live inventory platform integrated with POS & predictive AI Remittance App: Full ecosystem from KYC to payouts, FX, and compliance AI SaaS: Automated publication platform for medical/scientific professionals White-Labeled Payment Gateway: Delivered PCI-DSS-compliant multi-tenant platform for global merchants If you’re looking for a partner to help you deliver robust business platforms faster and with confidence — let’s connect.

More than 20 years of professional experience, expertise in Linux, C/C++, Python, Erlang, advanced algorithms, system analysis. Open to various offers, but mostly interested in Linux kernel, currently. Fixing bugs, solving complicated problems, creating / reshaping systems. The result is most important of all things. There are no borders between various disciplines of programming. A high power output, not for every appliance. :) Getting things done.

100M+ players have played games I’ve helped build. Over the past 8+ years, I’ve worked on commercial Unity titles across mobile, multiplayer, Steam, AR/VR, and live-service games for studios ranging from startups to globally recognized companies Over the last 8+ years, I’ve worked on Unity, C#, multiplayer, mobile game development, PlayFab, Photon, backend systems, optimization, LiveOps, game design, and store launches. My portfolio includes world-class titles such as Zynga Poker, WWE Champions, WWE Undefeated, War Dragons, Poker VR, and other projects reaching 100M+ players. If you need a Unity Game Developer who can take your game from prototype to polished launch-ready product, I can help with the full pipeline. What I specialize in: • Unity 2D/3D game development • Mobile game development for iOS and Android • Steam and PC game development • Multiplayer game development • Photon, Photon Fusion, Mirror, Netcode, FishNet • PlayFab backend, authentication, leaderboards, economy, cloud scripts • Firebase, GameAnalytics, AdMob, Unity Mediation, IAP • Game design, progression systems, economy, monetization, LiveOps • AR/VR/XR development for Meta Quest, HoloLens, and AR Foundation • UI/UX implementation, gameplay polish, optimization, and publishing I build games with clean C# architecture, scalable systems, modular gameplay code, strong performance, and production-ready structure. Whether you need a mobile game, multiplayer game, Steam game, PlayFab backend, Photon multiplayer system, AR/VR experience, casual game, hypercasual game, hybrid-casual game, MMORPG prototype, co-op game, or full game development from scratch, I can handle it end to end. Why clients hire me: • 8+ years of Unity and C# experience • 100M+ players reached across shipped titles • Experience with mobile, Steam, multiplayer, AR/VR, and live-service games • Strong understanding of gameplay, backend, optimization, monetization, and publishing • Clear communication, fast execution, and reliable delivery • Ability to work as developer, technical lead, game designer, and product partner I don’t just write code. I help shape games into products that feel good, scale properly, and are ready for real players. If you’re looking for a senior Unity Game Developer for Unity, C#, mobile game development, multiplayer, PlayFab, Photon, Steam, backend, LiveOps, AR/VR, or full game development, send me a message and let’s discuss your project.

👋 Hi there! ✅ 100% Job Success Score ⭐ 5★ Reviews on Upwork 💼 CTO | Full-Stack Web Architect | 14+ Years of Experience 🚀 Expert in Microsoft Tech Stack, crafting scalable and high-performing web applications 💡 Fun Fact: I leverage AI tools like ChatGPT to boost productivity, solve problems, and deliver faster results 🌟 Core Skills & Expertise 1. Backend Development: .NET Core, ASP.NET MVC, Web API, Entity Framework Core 2. Frontend Development: AngularJS, Blazor, Telerik Controls, Kendo UI, Responsive UI 3. Web APIs & Services: RESTful API Design, JWT, OAuth Authentication 4. Database Management: SQL Server, MySQL, PostgreSQL, Query Optimization 5. DevOps & Agile: Azure DevOps, CI/CD Pipelines, GitHub Actions, Jenkins 6. Code Quality: Unit Testing (xUnit, NUnit, MSTest), Clean Code Principles ✨ Additional Strengths 1. Solid grounding in OOP, SOLID, and Design Patterns 2. Expertise in Git, TFS, SVN for seamless version control 3. Skilled in RDLC Reporting for actionable analytics 4. Ability to convert complex business workflows into elegant technical solutions 🏆 Certifications 1. Agile Scrum Master – Simplilearn (Feb 2025) 2. Advanced Blazor WebAssembly – Simplilearn (Feb 2025) 3. GitHub Copilot Fundamentals – Simplilearn (Feb 2025) 4. Introduction to ASP.NET – Simplilearn (Feb 2025) 🤝 Why Work with Me? 1. Proven Track Record: 100% Job Success Score & 5★ Reviews 2. CTO Mindset: Balancing Tech Vision with Business Goals 3. Passionate About Clean, Scalable, Maintainable Code 4. Thrive in Agile Teams (Scrum, Kanban) 5. Committed to Timely Delivery & Robust Solutions 📌 Let’s connect and bring your next project to life! 🚀 #CTO #ASPNETExpert #AngularDeveloper #DotNetCore #Blazor #MAUIDevelopment #RESTAPI #SQLServer #RxJS #MaterialDesign #UnitTesting #AzureDevOps #GitHubPortfolio #FullStackDeveloper #AIProductivity

I am a Microsoft Certified Full Stack Developer with over 14 years of experience building scalable AI-powered enterprise SaaS platforms, VoIP systems, POS solutions, Internal Dashboards, E-commerce, and MVP development. I specialize in solving complex business problems using modern full-stack technologies and real-world AI integrations and AI Coding. 𝐊𝐞𝐲 𝐄𝐱𝐩𝐞𝐫𝐭𝐢𝐬𝐞: 𝐅𝐮𝐥𝐥 𝐒𝐭𝐚𝐜𝐤: .NET Core, ASP.NET, C#, Entity Framework, Blazor, Node.js, Python (Fast API), React, Angular, Next.js, TypeScript. 𝐀𝐈 & 𝐀𝐮𝐭𝐨𝐦𝐚𝐭𝐢𝐨𝐧: OpenAI, LLMs, AI Agents, Voice AI, Chatbot, RAG Systems, Workflow Automation. 𝐀𝐫𝐜𝐡𝐢𝐭𝐞𝐜𝐭𝐮𝐫𝐞: Multi-tenant SaaS, Microservices, REST APIs, Cloud (AWS/Azure), Third-party APIs like- Twilio, Stripe, etc. 𝐈𝐧𝐝𝐮𝐬𝐭𝐫𝐢𝐞𝐬: Healthcare IoT, Fintech, E-commerce, Telecommunication, HR, and others. I focus on clean architecture, long-term maintainability, and transparent communication. With a 100% Job Success Score and 16,000+ hours on Upwork, I deliver secure, high-performance solutions that drive product growth. Let’s discuss how I can help bring your project to life. Best regards, Harsh K.

I build production-ready .NET 8 systems that scale — from AI-integrated SaaS platforms to healthcare EMR solutions processing thousands of daily transactions. 100% Job Success, $100K+ delivered on Upwork. As a Microsoft-focused Software Engineer with 8+ years of experience, I design, develop, and maintain scalable web, desktop, and enterprise applications using .NET Core, ASP.NET MVC, C#, Web APIs, SQL Server, Azure, and modern JavaScript frameworks. I specialize in understanding complex business requirements, quickly onboarding existing codebases, and delivering reliable solutions that are maintainable, scalable, and production-ready. Core Expertise ✅ ASP.NET Core, .NET 6/7/8/9/10, MVC, Razor Pages, Blazor ✅ REST APIs, Microservices, Clean Architecture, SOLID Principles ✅ SQL Server, Entity Framework Core, Query Optimization, Database Design ✅ Azure Cloud Services, CI/CD Pipelines, Azure DevOps ✅ React, Angular, JavaScript, jQuery, HTML5, CSS3 ✅ Desktop Applications (WPF, WinForms) ✅ SaaS Platforms, ERP Systems, Workflow Automation, POS Solutions AI & Modern Development I actively work with modern AI-powered development workflows and have experience integrating: ✅ OpenAI APIs and AI-powered features ✅ AI-driven document processing and automation workflows ✅ Claude Code, GitHub Copilot, Cursor, and AI-assisted development ✅ AI-enhanced SaaS and business applications I understand that successful AI projects require more than API integration—they require proper architecture, workflow design, security, scalability, and business-focused implementation. I help clients transform AI ideas into practical, production-ready solutions. Recent Project Experience 🏥 Healthcare & EMR Systems with HL7/ASTM integrations ☁️ Azure-based enterprise applications and cloud deployments 📊 Workflow automation and reporting platforms 🏢 ERP, CRM, and business management systems 🛒 E-commerce and transaction-based applications 📱 Cross-platform and desktop business applications What Clients Value ✔ Delivered $56K enterprise .NET project with 2,271 hours — zero scope creep ✔ Cut EMR paperwork by 40% through custom workflow automation ✔ Onboarded complex legacy codebases within days, not weeks ✔ Strong communication ✔ Fast understanding of existing systems ✔ Clean and maintainable code ✔ Problem-solving mindset ✔ Long-term reliability and support Whether you need a developer to build a new platform, modernize an existing application, optimize performance, integrate AI capabilities, or maintain a complex enterprise system, I can help deliver a solution that supports your business goals. Let's discuss how I can contribute to your project.

𝐒𝐞𝐧𝐢𝐨𝐫 𝐀𝐈, 𝐒𝐚𝐚𝐒 & 𝐂𝐥𝐨𝐮𝐝 𝐀𝐫𝐜𝐡𝐢𝐭𝐞𝐜𝐭 | 𝐋𝐋𝐌, 𝐑𝐀𝐆, 𝐈𝐨𝐓, 𝐀𝐮𝐭𝐨𝐦𝐚𝐭𝐢𝐨𝐧 | 𝟖+ 𝐘𝐞𝐚𝐫𝐬 I help founders and startups build production-ready AI, SaaS, IoT and cloud products that are scalable, secure and commercially practical. 𝐖𝐢𝐭𝐡 𝟖+ 𝐲𝐞𝐚𝐫𝐬 𝐨𝐟 𝐞𝐱𝐩𝐞𝐫𝐢𝐞𝐧𝐜𝐞, 𝐈 𝐰𝐨𝐫𝐤 𝐚𝐜𝐫𝐨𝐬𝐬 𝐋𝐋𝐌 𝐚𝐩𝐩𝐥𝐢𝐜𝐚𝐭𝐢𝐨𝐧𝐬, 𝐑𝐀𝐆 𝐬𝐲𝐬𝐭𝐞𝐦𝐬, 𝐀𝐈 𝐚𝐮𝐭𝐨𝐦𝐚𝐭𝐢𝐨𝐧, 𝐒𝐚𝐚𝐒 𝐩𝐥𝐚𝐭𝐟𝐨𝐫𝐦𝐬, 𝐈𝐨𝐓 𝐩𝐫𝐨𝐝𝐮𝐜𝐭𝐬, 𝐡𝐞𝐚𝐥𝐭𝐡𝐜𝐚𝐫𝐞 𝐬𝐨𝐟𝐭𝐰𝐚𝐫𝐞 𝐚𝐧𝐝 𝐟𝐮𝐥𝐥-𝐬𝐭𝐚𝐜𝐤 𝐝𝐞𝐯𝐞𝐥𝐨𝐩𝐦𝐞𝐧𝐭. 𝐌𝐲 𝐟𝐨𝐜𝐮𝐬 𝐢𝐬 𝐧𝐨𝐭 𝐨𝐧𝐥𝐲 𝐭𝐨 𝐬𝐡𝐢𝐩 𝐟𝐚𝐬𝐭, 𝐛𝐮𝐭 𝐭𝐨 𝐛𝐮𝐢𝐥𝐝 𝐬𝐲𝐬𝐭𝐞𝐦𝐬 𝐭𝐡𝐚𝐭 𝐜𝐚𝐧 𝐬𝐜𝐚𝐥𝐞 𝐰𝐢𝐭𝐡𝐨𝐮𝐭 𝐜𝐨𝐬𝐭𝐥𝐲 𝐫𝐞𝐰𝐨𝐫𝐤 𝐥𝐚𝐭𝐞𝐫. 𝐖𝐡𝐚𝐭 𝐈 𝐛𝐮𝐢𝐥𝐝 --------------------------------------------- 1. AI products using OpenAI, Claude, RAG, prompt workflows and automation 2. SaaS platforms, dashboards, APIs and multi-tenant systems 3. AI automation with n8n, Make, internal tools and workflow systems 4. IoT and connected device platforms with telemetry, dashboards and monitoring 5. Web and mobile products using Python, Node.js, React, Next.js, TypeScript, Wordpress Custom Development 𝐌𝐲 𝐰𝐨𝐫𝐤 𝐰𝐡𝐢𝐜𝐡 𝐜𝐫𝐞𝐚𝐭𝐞𝐝 𝐚𝐧 𝐈𝐦𝐩𝐚𝐜𝐭 ---------------------------------------------------------- 1. Biosensor – built connected health monitoring workflows, improving data reliability by 35% 2. Topmate – improved product workflows and platform scalability for growth 3. Bolna.ai – built AI conversational workflows and backend automation 4. Conviva.ai – Developed AI workflow architecture and production readiness 5. Brex - Finance platform an automated reconciliation and audit-friendly finance workflows 𝐂𝐨𝐫𝐞 𝐬𝐤𝐢𝐥𝐥𝐬 ------------------------------------------ Python, Node.js, TypeScript, React, Next.js, FastAPI, Spring Boot, AWS, Azure, Docker, Kubernetes, LLM, RAG, Claude AI, OpenAI, n8n, AI Automation, SaaS Architecture, IoT, Healthcare Product Development, Wordpress, Php, IoT, Firmware Development, C++, C+ If you need someone who can combine architecture thinking with hands-on delivery, I’d be happy to help. 𝐃𝐢𝐯𝐚𝐤𝐚𝐫 𝐒𝐢𝐧𝐠𝐡 8+ 𝘆𝗲𝗮𝗿𝘀 E𝘅𝗽𝗲𝗿𝗶𝗲𝗻𝗰𝗲

𝐖𝐞𝐥𝐜𝐨𝐦𝐞 𝐭𝐨 𝐦𝐲 𝐩𝐫𝐨𝐟𝐢𝐥𝐞 7+ Years of Software Development Experience Expert in Building Scalable Web Applications, APIs, and SaaS Platforms Delivered CRM Systems, Enterprise Applications & Cloud-Based Solutions I help startups, founders, and enterprises turn their ideas into reliable and scalable digital products. From building applications from scratch to improving existing platforms, I focus on delivering secure, high-quality, and maintainable solutions. If you are looking for an experienced developer who can understand your business needs and build efficient software solutions, you are in the right place. 𝐖𝐇𝐘 𝐂𝐋𝐈𝐄𝐍𝐓𝐒 𝐂𝐇𝐎𝐎𝐒𝐄 𝐌𝐄 • 7+ years of experience • Strong knowledge of web application development • Experience with SaaS and enterprise solutions • API development and integrations • Clean and maintainable code 🚀 𝐓𝐞𝐜𝐡𝐧𝐢𝐜𝐚𝐥 𝐒𝐤𝐢𝐥𝐥𝐬 Backend • .NET, C#, ASP.NET, .NET Core • Node.js • REST & SOAP APIs • Microservices • JWT, OAuth Frontend • React.js • JavaScript, TypeScript • HTML, CSS ☁️ 𝐂𝐥𝐨𝐮𝐝 & 𝐃𝐞𝐯𝐎𝐩𝐬 • Docker • CI/CD • Cloud deployment 🗄 𝐃𝐚𝐭𝐚𝐛𝐚𝐬𝐞 • PostgreSQL, MSSQL, MySQL • MongoDB, Redis, Firebase 𝐎𝐭𝐡𝐞𝐫 𝐒𝐤𝐢𝐥𝐥𝐬 • Agile / Scrum • System design • Debugging & optimization • Git, Jira, Trello 𝐂𝐋𝐈𝐄𝐍𝐓 𝐅𝐄𝐄𝐃𝐁𝐀𝐂𝐊 "Thank you for helping build our application based on the requirements. We look forward to working together again." "Great communication and high-quality work delivered on time." "Excellent code quality and professionalism. Highly recommended." 𝐋𝐞𝐭’𝐬 𝐖𝐨𝐫𝐤 𝐓𝐨𝐠𝐞𝐭𝐡𝐞𝐫 Thanks & Regards Sumit

⭐ Top Rated Plus | 100% Job Success Hey! I'm Dubravko, a Solutions Architect with 7+ years of experience and the founder of Altitude IT, a co-located team of engineers in Serbia. We're not a faceless outsource shop. I'm hands-on in every project, managing my team and staying close to the work so nothing slips through the cracks. We also work alongside a partner design agency in our office, so we can cover the full product lifecycle from UI to infrastructure. We build systems that need to stay up when traffic spikes and complexity grows. A few examples of what that looks like in practice: -Built an API-driven platform that integrates with 20+ major airlines, automating rebookings, refunds and passenger data updates, used both as a standalone booking app and as a unified API that other businesses plug into their own systems. -Developed a real-time sports data aggregation platform handling live scores, schedules and news across soccer, basketball, baseball, NFL and Formula 1, restructured the data layer and optimized MongoDB to keep things fast under heavy load. -Created a FinTech commission management system that automated payment calculations, receipt matching, invoice generation and role-based access, cutting manual processing time and errors significantly for the client. -Shipped cross-platform mobile apps in e-commerce and education (React Native + Golang), including a grocery app with barcode scanning and payments, and a student discount app with QR codes and interactive maps. -Deployed Prometheus + Grafana monitoring on AWS EKS with Kubernetes and Helm for proactive infrastructure observability. Our stack: Backend: Golang, .NET, Node.js, Python | Frontend: React, Next.js, Angular, React Native | Infrastructure: AWS, DigitalOcean, Kubernetes | Databases: PostgreSQL, MongoDB, Redis, MySQL | Tooling: Prometheus, Grafana, Power BI How we work: We take on and prefer long-term engagements, multi-year relationships, not one-off handoffs. Communication is direct, clear and on time. I plan and architect every project before a line of code is written, and we iterate closely with clients throughout. If something breaks at 2am, we're the ones fixing it. Ready to talk? Send me a message and let's figure out if we're a good fit.

Looking to turn your idea into a secure, scalable, production-ready software product? I help startups and growing businesses design and build high-performance web, mobile, SaaS, and AI-enabled applications from concept to deployment. I work across full SDLC from architecture and backend systems to modern frontend apps, APIs, cloud deployment, and intelligent automation. I regularly build SaaS platforms, business systems, dashboards, automation tools, AI features, and integration-heavy applications used in real production environments. Whether you need a new platform, MVP, API layer, admin panel, AI feature, or legacy system modernization I can help you plan, build, and launch with clarity and zero surprises. What I Can Build For You ✔ SaaS platforms & MVP products ✔ Full stack SaaS web & mobile applications ✔ AI-enabled features & intelligent workflows ✔ REST & GraphQL APIs ✔ Dashboards & admin systems ✔ Business automation platforms ✔ Microservices architectures ✔ Cloud-ready scalable systems ✔ Integration-heavy platforms Industries I've Worked With: Over the past decade, I’ve worked with multiple teams and product owners across diverse industries, building scalable software platforms, SaaS systems, AI-enabled applications, and business-critical tools. Some of the key domains include: → Healthcare: EHR/EMR systems, Telehealth platforms, Scheduling systems, Patient Management, Pharmacy Apps, Healthcare Portals → FinTech: Payment Gateway Integrations, Trading Apps, Portfolio Platforms, Loan Management Systems → EdTech: Learning Platforms, LMS systems, Student Dashboards, Data Analytics Solutions → Logistics & Operations: ERP platforms, Tracking Systems, Fleet & Operations Tools, → Real Estate & Construction: Property Management Platforms, Construction Project Management Systems → Marketplaces: Product & Service Marketplaces, AI-Powered Marketplaces → HR & Recruitment: AI-Powered Hiring & Recruitment Management Systems, Applicant Tracking Systems (ATS) → Travel & Aviation: Flight Booking Platforms, Travel Portals → Non-Profit & Organizations: Nonprofit Management Platforms, Donation Tracking Systems → Event Management: Event Apps, Ticketing Systems → Sports & Fitness: Sports Apps, Training & Performance Tracking Platforms → E-commerce: B2C & B2B E-commerce Applications, Order & Inventory Systems → Insurance & Finance Ops: Claims Processing Platforms, Policy & Case Management Systems My Core Technical Expertise: Frontend: → Blazor (WebAssembly & Server) | React.js | Vue.js | Angular | Next.js → TypeScript | JavaScript | jQuery | HTML5 | CSS3 → Responsive Design | Component-Based UI | Mobile-First UI | SPA Development → Tailwind CSS | Bootstrap | Material UI Backend: → C# | .NET Core | ASP.NET Core | Node.js | Blazor | ASP.NET MVC → Entity Framework Core | Dapper | LINQ | ORM Frameworks → API-First Development | REST APIs | GraphQL APIs → Microservices Architecture | Distributed Systems → Domain-Driven Design (DDD) | Onion Architecture | Clean Architecture Databases & Data Layer: → SQL Server | PostgreSQL | Azure SQL | MongoDB | MySQL → Firebase | Cosmos DB | Redis → Data Modeling | Query Optimization | Multi-Tenant Systems → Caching | Performance Tuning | Data Architecture Cloud & Devops: → Azure Specialist | AWS | Google Cloud Platform (GCP) → Docker | Kubernetes | Azure Kubernetes Service (AKS) → Containerized Applications | Microservices Deployment → CI/CD Pipelines | Continuous Integration | Continuous Deployment → Version Control: GitHub | Azure Repos | Git → Infrastructure as Code: Terraform → Monitoring & Observability: Application Insights | Datadog | New Relic → Security & Monitoring Tools: Sentinel | Trend Vision AI & Automation : → OpenAI / ChatGPT API | LLM Integrations | AI Features in Apps → Smart Workflows | AI Chatbots | AI Agents → Automation for Business Efficiency | Semantic Search → AI-Powered SaaS Features | Intelligent Document Processing → Workflow Automation | Process Automation ⭐ 𝐊𝐞𝐲𝐰𝐨𝐫𝐝𝐬: [ Full Stack Developer, AI Developer, ASP.NET Core, C# Developer, .NET Core, SaaS Development, MVP Development, Microservices Architecture, REST API Development, GraphQL API, Backend Developer, Frontend Developer, Angular, React, Blazor WebAssembly, TypeScript, JavaScript, Web Application Development, Mobile App Development, Dashboard Development, Business Automation, AI Integration, OpenAI API, ChatGPT API, LLM Integration, Workflow Automation, Cloud Development, Microsoft Azure, AWS, Docker, Kubernetes, CI/CD, DevOps, SQL Server, PostgreSQL, MongoDB, Redis, Entity Framework Core, Multi-Tenant SaaS, Enterprise Applications, Database Design, Performance Optimization ] Whether you're starting from scratch or improving an existing system, let’s talk about how we can turn your idea into a successful product.