Hire the Best .NET Framework C# Engineers in New York

Looking for professionalism, fast delivery times, strict adherence to software development best practices, and deep expertise in today’s top technologies? Then let’s talk. I’m Alain Alvarez, a Senior .NET Engineer with over 20 years of experience delivering scalable, maintainable, and high-performance solutions across startups, agencies, and enterprise environments. I specialize in clean architecture and full-stack development using C#, ASP.NET Core, and the .NET Framework, with hands-on experience in both modernizing legacy systems and building cloud-native platforms from the ground up. I apply Domain-Driven Design (DDD) and Clean Architecture principles to ensure robust, modular, and future-ready code. I’ve also expanded my tech stack to include modern tools such as React, Next.js, Node.js, NestJS, and MongoDB, enabling me to bridge traditional enterprise backends with high-performance, user-friendly frontend and modern micro-services. Key Expertise: • Full-stack development with C#, ASP.NET Core, .NET Framework, Web APIs • UI/UX development with React, Blazor, Next.js • Scalable backend services with Node.js, NestJS • Data modeling with SQL Server and MongoDB • Cloud deployment using Azure Functions, App Services, API Management • Secure identity with OAuth 2.0, OpenID Connect • Automated testing and delivery pipelines with xUnit, GitHub Actions, CI/CD I bring not just technical skills, but a strategic mindset and a commitment to delivering clean, reliable, and high-quality software on time, and aligned with your business goals. Let’s build something solid, smart, and scalable.

Software Engineer with over eight years of experience developing products and features using the .NET ecosystem and deploying using cloud services such as AWS and Microsoft Azure. Specializes in backend systems, relational database operation and management, 3rd party integrations, and cloud service integrations.

✅ I HELP SOLVE YOUR TECH PROBLEMS, SIMPLE AS THAT. ✅ I'LL LEVERAGE MY DECADES OF EXPERIENCE AS A FULL-STACK WEB DEVELOPER / SYSTEMS ARCHITECT / TECHNICAL LEAD / TECH MANAGER / FRACTIONAL CTO – WITH TOP COMPANIES – to get your project done correctly and cost effectively, using a problem-solving approach honed over decades of experience in the industry, capped off with excellent communication skills. ✅ IF YOU NEED AN ENTIRE TECH TEAM ASSEMBLED, LARGE OR SMALL... – If, instead of my individual services, you’re looking for a team to be built out to work on your project, I will use my many years of tech management experience to assemble and personally manage that team, ensuring the highest quality of delivered work, following industry best practices, and engaging my personal philosophy of software development that I have fine-tuned over my decades-long career. ————————————————————————— MY NAME IS MICHAEL R. KLOSNER, AND I'M HERE TO HELP YOU: ➠ OVER 15 YEARS EXPERIENCE IN THE INDUSTRY ➠ UPWORK EXPERT-VETTED (TOP 1% FREELANCER) STATUS ➠ 100% 5-STAR REVIEWS FROM ALL MY CLIENTS. ✅ I’VE DEVELOPED / MANAGED FOR WORLD-FAMOUS COMPANIES / ORGANIZATIONS JPMorgan • March of Dimes • MultiView • Cartier • SEI • Festo • More... ✅ I’M A TOP 1% RATED FREELANCER, EXPERT-VETTED BY UPWORK The Upwork Expert-Vetted program identifies the top 1% of talent on the platform. All Expert-Vetted freelancers undergo a rigorous screening process. ✅ I HAVE A 100% 5-STAR RATING ⭐⭐⭐⭐⭐ 100% satisfaction and 5-Star ratings from every single one of my Upwork clients, who trust me with their most sensitive software products and executive-level decision making for their companies. ✅ HERE'S WHAT A RECENT MAJOR UPWORK CLIENT HAD TO SAY "Working with Michael was a seamless experience. He is highly skilled, timely, and brings a great deal of technical talent to the table. What stood out most was his ability to provide practical advice that saved us time and resources. He navigated every challenge we threw at him with a 'problem-solver' mindset. I will definitely be hiring him again for future software needs!" ✅ YALE-EDUCATED COMPUTER SCIENTIST I hold a B.Sc. in Computer Science from Yale University and an M.Sc. in Marine Biology from the University of the Algarve in Faro, Portugal. I have studied directly under leading experts in Computer Science, including winners of the Turing Award, the highest distinction in the field. ✅ EXCELLENT COMMUNICATOR Top clients specifically choose to work with me because they value the clear and concise communication that I provide throughout the entire lifecycle of the project. Whether with my clients themselves, with senior or junior developers, non-technical staff, investors or potential customers, I have a proven track record of excellent written and spoken communication skills, both with individuals and small or large groups. ✅ LET’S GET YOUR PROJECT DONE THE RIGHT WAY! Take a moment to text me with answers to the following 3 questions, and I’ll get back to you, within 24 hours, with a detailed response: 1. What is the nature (scope) of your project and what is the ultimate goal of your business / organization? 2. What is the single major technological block you are facing right now that prevents you from completing the project? 3. If you could have your project done the right way, what exactly would that look like to you? ————————————————————————— MICHAEL R. KLOSNER ➠ Upwork Expert-Vetted / 100% Client Satisfaction ➠ Full Stack Developer ➠ Systems Architect ➠ Tech Manager ➠ Fractional CTO ➠ 15+ Years Experience SELECTED TECHNICAL EXPERTISE ➠ Technology Management, CTO, VP Engineering, Lead Developer ➠ NET Core (7,8,9) / .NET Framework, MVC, C#, C++, C ➠ JavaScript, React.js, Node.js, Express.js, jQuery, TypeScript, Angular, Wix Blocks (Velo) ➠ SQL, SQL Server, MySQL, Stored Procedures, NoSQL (MongoDB), Entity Framework ➠ eCommerce Integration, Stripe, Amazon Payments, PayPal, Shopify ➠ SSO, OAuth, Okta, OpenID Connect (OIDC), JWT, 2FA ➠ DevOps, Azure Cloud, AWS (EC2, RDS, EBS), SDLC, Git, Atlassian ➠ HTML 5, CSS 2/3, XML, XSLT, JSON, AJAX / Fetch / Axios ➠ REST API, Web API, Zapier, Webhooks, ActiveCampaign, SendGrid, Lucene / SOLR, WordPress, PHP, Java ➠ Agile, Scrum, Clean / SOLID Architectures, Headless Stack / CMS ➠ Systems Architecture, Mathematics, Matlab, Signal processing, R (Statistics) / RStudio

I help game teams and indie developers fix, build, and improve Unity/C# projects, including gameplay systems, multiplayer, backend integrations, PlayFab, debugging, and tools. I’m a senior C#/.NET and Unity developer with 10+ years of professional engineering experience. I’m also the founder and lead Unity developer of Race Jam, a shipped multiplayer Steam racing game with 10,000+ downloads. I’m strongest in projects where you need someone who can quickly understand an existing codebase, diagnose problems, and deliver clean, practical fixes. Best fit projects: • Unity/C# bug fixing • Gameplay systems • Unity Netcode / multiplayer issues • PlayFab leaderboard or backend integration • Unity editor tools • Prototype cleanup • Performance/debugging support • C#/.NET API or automation work Relevant experience: • Race Jam — a multiplayer Unity racing game released on Steam • Guavas — an iOS application built with Swift and AWS EC2 infrastructure • Built race systems including checkpoint validation, lap tracking, placement sorting, and race/session flow • Implemented online multiplayer using Unity Netcode • Integrated Azure PlayFab leaderboard functionality • Built production C#/.NET, SQL, AWS, and automation systems across 10+ years I’ve also hired and managed contractors myself, so I understand the client side of Upwork: clear scope, reliable communication, milestone-based delivery, and no surprises.

Turning Software engineering into scalable cloud infrastructure and Rest API design. My journey started in data science & analytics, where I built Python tools to clean. process, and analyze complex datasets. While working with data pipelines and automation, I developed a strong interest in backend systems and cloud infrastructure, which led me to specialize in Python engineering and Cloud DevOps. I now design and automate scalable AWS infrastructure using Python and Infrastructure as Code (IaC) to support modern application and data-driven systems. I previously worked as an AWS Infrastructure & CDK Engineer at TrendzAct, where I designed and deployed production-grade cloud environments and automated provisioning using Python-based AWS CDK projects and AI-based applications. Instead of manual setup, I focus on automated, repeatble, and secure infrastructure that allows teams to deploy faster and scale efficiently. What I Can Help With • Design scalable AWS cloud architectures • Build Infrastructure as Code using Python and AWS CDK, Terraform, Kubernetes • Automate deployment pipelines and cloud provisioning • Design VPC networks, VPN connectivity, and secure cloud environments • Migrate on-premise systems to AWS • Deploy backend systems using Lambda, ECS, EC2, and API Gateway • Optimize infrastructure for cost, scalability, and performance Technologies & Tools Programming Python (Automation, Cloud Engineering, Data Science), .NET, Java, Node.js Cloud Platforms AWS • GCP • Azure AWS Services EC2 • Lambda • API Gateway • ECS • RDS • VPC • IAM • S3 • Cognito • CloudFront • SNS • SES • SQS • CloudWatch Infrastructure as Code Python CDK • Terraform • Kubernetes • SAM • Cloud Automation Databases MSSQL • MongoDB • SQL • Aurora • DynamoDB • MongoDB Front End React •  Angular •  Vue Other Skills Linux • Networking • Cloud Security • Solution Architecture, Zoho CRM, HubSpot, Mailchimp AI Claude • N8N • OpenAI • LLM If you need AWS infrastructure automation, cloud migration or scalable backend systems, feel free to reach out.

My specialty and proven track record is enabling founders to go from idea to production rapidly using an AI-driven, agentic software development process built around the following AI-centric pipeline: Discovery → AI Transcription → AI-Optimized Spec → Test-first Development → AI and Human Code Review → Iterative Delivery → Production Claude Cowork was written in 10 days utilizing this process. My background: I’m a US based Fractional CTO & Software Architect with 20+ years of experience leading startups to funding. This combined with extensive experience leading mission-critical initiatives at large organizations like The Federal Reserve and Fannie Mae. I work best with founders who want to move fast, stay lean, and get to a real, working product without unnecessary complexity. Let's build something great.