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Full-Stack Developer — ASP.NET, Legacy .NET & React Remote | Full-Time About the Role We're looking for a versatile Full-Stack Developer to help us maintain, modernize, and extend our software platform. You'll work across a mix of legacy .NET Framework applications and modern ASP.NET Core services, while building and improving user-facing features in React. This is a great fit for someone who's comfortable bridging old and new — keeping critical systems running while helping guide their evolution. What You'll Do Maintain and enhance existing applications built on legacy .NET Framework (Web Forms, MVC, or WCF) Design, build, and maintain services and APIs using ASP.NET Core Develop responsive, maintainable front-end features using React Participate in modernization efforts — refactoring legacy code, migrating to .NET Core/5+, and improving overall architecture Write clean, well-tested, maintainable code and participate in code reviews Collaborate with product managers, designers, and other engineers to scope and deliver features Troubleshoot and resolve production issues across the stack Contribute to technical documentation and internal best practices What We're Looking For 5+ years of professional experience with C# / .NET, including exposure to legacy .NET Framework applications Solid experience with ASP.NET Core (Web API, MVC, or Razor Pages) Hands-on experience building UI with React (hooks, component architecture, state management) Working knowledge of SQL Server or another relational database Comfort working with REST APIs and understanding of software design patterns Experience with Git and collaborative development workflows Strong problem-solving skills and the ability to work independently across unfamiliar codebases Nice to Have Experience with Azure or AWS Familiarity with CI/CD pipelines Exposure to TypeScript Experience modernizing or migrating legacy systems Understanding of microservices or service-oriented architecture Salary range: $1500 - $2000 / month
Project ID: 40655754
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63 freelancers are bidding on average $1,873 USD for this job

Greetings! I am a full-stack developer comfortable working across both legacy .NET Framework applications and modern ASP.NET Core services, with solid experience building front-end features in React. I can maintain and enhance your existing systems while contributing to modernization efforts, including refactoring legacy code and migrating to newer frameworks. I write clean, testable code and am experienced with SQL Server, REST APIs, Git workflows, and collaborative development. I am also comfortable troubleshooting production issues and working independently across unfamiliar codebases. I have exposure to Azure and CI/CD pipelines, and I am ready to help bridge your old and new systems while improving overall architecture. I am available for full-time remote work and would be happy to discuss how I can support your platform's evolution. Thanks, Revival
$1,500 USD in 7 days
8.0
8.0

Hi — Elias here from Miami. I see you're looking for full-stack developers with a solid grasp of ASP.NET, Legacy .NET, and React. The goal is to create reliable and effective applications that not only meet current needs but are also prepared for future demands. What usually matters most here is ensuring maintainability and scalability. A common issue in systems like this is managing legacy code alongside new frameworks, which can complicate updates and integration. The tricky part is usually aligning the workflows between different tech stacks to ensure a seamless user experience. My approach would involve structuring your application with clear separation of concerns, using best practices for both the legacy components and modern frameworks. This ensures stability and simplifies future enhancements. I’ve worked on similar projects where I integrated .NET solutions with modern front-end technologies, allowing for efficient collaboration between teams. A few questions to better understand the scope: Q1 – What user roles and permissions will the application need? Q2 – Are there any specific integrations with existing systems you envision? Q3 – What are your scaling expectations in terms of user load and data growth? Happy to go through the details and suggest the best technical approach. Looking forward to hearing from you.
$2,500 USD in 10 days
6.9
6.9

HELLO, I AM BASED IN INDIA AND HAVE CAREFULLY REVIEWED YOUR REQUIREMENTS FOR THE FULL-STACK DEVELOPER ROLE. I HAVE 10+ YEARS OF EXPERIENCE WITH C#, .NET, ASP.NET CORE, LEGACY .NET FRAMEWORK, WEB API, MVC, REACT, SQL SERVER, REST APIs, GIT, AND CLOUD-BASED APPLICATIONS. I AM COMFORTABLE WORKING WITH EXISTING CODEBASES, TROUBLESHOOTING PRODUCTION ISSUES, MODERNIZING LEGACY SYSTEMS, AND DEVELOPING NEW FEATURES ACROSS THE FULL STACK. MY APPROACH → Review Existing Codebase → Understand Architecture → Fix & Enhance Legacy Modules → Develop ASP.NET Core APIs → Build React Features → Database/API Integration → Testing & Code Review → Deployment & Documentation. I AM COMFORTABLE WORKING FULL-TIME REMOTELY, COLLABORATING WITH YOUR TEAM, AND CONTRIBUTING TO LONG-TERM MODERNIZATION AND MAINTENANCE. I WILL FOLLOW AGILE METHODOLOGY AND PROVIDE 2 YEARS OF FREE ONGOING SUPPORT FOR THE WORK DELIVERED. I EAGERLY AWAIT YOUR POSITIVE RESPONSE. THANKS
$1,500 USD in 7 days
6.0
6.0

Hi, I reviewed the role and I can maintain and modernize a platform across legacy .NET Framework and modern ASP.NET Core, while building React front-end features. I’ll work on legacy Web Forms/MVC/WCF apps, design and maintain ASP.NET Core services and APIs, and implement responsive React components with clean state management. I’ll also write technical documentation, contribute to code reviews, and troubleshoot production issues across the stack. With SQL Server, I can support reliable data access and REST API usage, keeping the codebase maintainable for future migrations. You’ll get well-tested, readable work and responsive collaboration. Let’s discuss here now.
$1,500 USD in 30 days
5.5
5.5

The part that usually breaks on jobs like this is the bridge between legacy .NET Framework and modern ASP.NET Core with React, so I will start there. I will maintain and enhance the legacy .NET Framework applications using Visual Studio, focusing on the specific technologies you mentioned like Web Forms or MVC. For the modern services and APIs, I will use ASP.NET Core and C#, building out RESTful APIs. For the front-end features, I will build and improve them in React, using functional components and hooks with a state management library like Redux or Zustand. I will not be setting up a new CI/CD pipeline from scratch if you already have one, so I will integrate with your existing tooling. I am a Preferred Freelancer on Freelancer with a 5.0 rating, 100% on time and 100% on budget. That is the only past work, number, rating or result I mention. My approach to modernizing the platform is to identify specific components for refactoring and tackle them incrementally, so we reduce risk. What tooling are you using for the legacy .NET Framework applications currently, and will I be working with the existing source control or setting up a new repository? Let's set up a short call on Freelancer to cover the specific legacy .NET Framework technologies in use and the current state of your React codebase.
$2,395 USD in 21 days
4.3
4.3

Hello, I'm excited about the opportunity to work as a Full-Stack Developer on your software platform. I understand that you need someone who can maintain and enhance legacy .NET applications while also developing modern features in ASP.NET Core and React. With over 5 years of experience in C# and .NET, I have successfully worked with both legacy systems and modern frameworks. My expertise includes maintaining Web Forms and MVC applications, building robust APIs using ASP.NET Core, and creating responsive user interfaces with React. I have a strong grasp of SQL Server and REST APIs, ensuring that I can navigate and enhance your existing codebase effectively. To achieve your project goals, I would take the following approach: - Assess and refactor legacy code to improve maintainability and performance. - Develop new features in ASP.NET Core and React, focusing on scalability and user experience. - Collaborate closely with your team to gather requirements and ensure alignment. - Implement best practices for code quality and documentation throughout the development process. I am eager to contribute to your team and help modernize your platform while keeping critical systems running smoothly. I am confident in delivering quality results and can start immediately. Let's discuss how I can support your project further!
$1,500 USD in 7 days
4.3
4.3

Hi, Aashiq here from Cape Town, South Africa. This project instantly caught my eye, so I had to reach out. I see you’re looking for a Full-Stack Developer to maintain and modernize legacy .NET applications while also enhancing user-facing features in React. That blend of old and new is exactly where I thrive. With over 5 years of experience in C# and .NET, I have helped businesses transition from legacy systems to modern architectures, ensuring seamless functionality and user engagement. I can share samples of my successful projects that showcase my ability to bridge these technologies. Based on what you mentioned, here is how we would approach the project: - Assess existing legacy applications for immediate needs. - Develop modern ASP.NET Core services and responsive React components. - Collaborate closely with your team for effective feature delivery. - Establish a robust testing and documentation process. You can count on clear communication and a user-focused solution optimized for performance. Best Regards, Aashiq
$2,700 USD in 7 days
4.5
4.5

Hi, I checked your "Looking for Good Developers in Pakistan()" project description, it looks like the focus is on delivering a clean, responsive website that works well across all devices. I prefer understanding the expected layout and user experience first, then building pages that closely match the design while keeping the code organized and easy to maintain. Feel free to share the design or current website, and I'll suggest the best implementation along with a realistic timeline. Final timeline and cost will be confirmed in chat after a complete understanding and documentation of the project expectations in detail.
$1,500 USD in 59 days
4.2
4.2

GIVE ME 30 SECONDS TO SHOW YOU WHY I'M THE RIGHT FIT FOR THIS PROJECT. I recently modernized a legacy .NET application for a client, successfully migrating it to ASP.NET Core while enhancing its performance. This project resulted in a 30% increase in user engagement and significantly reduced maintenance costs. With over 6 years of experience in C# and .NET, including extensive work with legacy systems, I am adept at bridging old and new technologies. My hands-on experience with React and API development makes me a strong candidate for your needs. I understand your goal of maintaining existing applications while driving modernization. I propose to implement a phased approach, focusing on refactoring critical components and enhancing user interfaces to improve functionality and user experience. My commitment to clear communication and effective execution ensures long-term success for all projects I undertake. Let's transform your software platform together. The difference between an average result and an exceptional one is usually decided before the work even begins. Regards Patrick
$1,500 USD in 7 days
4.1
4.1

Hi, I can maintain and extend your existing .NET platform across both legacy and modern stacks, including C#, .NET Framework, ASP.NET Core, REST APIs, React, SQL Server, and Git. I can handle legacy Web Forms/MVC/WCF codebases, develop new ASP.NET Core services and React features, troubleshoot production issues, and gradually modernize older components without disrupting critical functionality. I’ll focus on clean, tested, maintainable code and reliable delivery across the full stack. Best regards, Shakila Naz
$2,000 USD in 30 days
3.8
3.8

Hey myself Shawana and I'm from Pakistan. I’m an experienced full-stack developer skilled in C#, .NET Framework, ASP.NET Core, React, SQL Server, REST APIs, and legacy system modernization. My approach: * Maintain and enhance legacy .NET applications safely. * Build scalable ASP.NET Core APIs and modern React features. * Refactor and migrate legacy components without disrupting existing functionality. * Follow clean architecture, testing, Git workflows, and performance best practices. * Collaborate closely with your team and provide clear progress updates. Q: Do you already have a roadmap or should I review the existing codebase ? I can share relevant .NET/React projects and discuss long-term availability. Regards Shawana
$1,500 USD in 7 days
3.9
3.9

Hi, I’ve worked with similar setups where legacy .NET applications needed gradual modernization without disrupting ongoing operations. The biggest challenge here is likely balancing the refactoring of Web Forms or WCF services with building new features in ASP.NET Core and React, all while keeping the system stable. In the past, I’ve migrated monolithic .NET apps to modular services by first isolating critical paths and replacing them incrementally. For the React side, I usually structure components to avoid tight coupling with legacy endpoints, which makes future replacements easier. SQL Server optimizations often come into play when performance issues surface after years of organic growth. The unknowns here are the depth of the legacy codebase and how tightly the UI still depends on it. Starting with a quick audit of the most fragile parts would help prioritize what to modernize first without overhauling everything at once. I can start working right away. Let's connect and discuss the details. Thanks, Denis.
$1,500 USD in 15 days
3.6
3.6

With over a decade of experience in the software development field, I bring both a deep understanding of legacy .NET technology and a mastery of modern tools like ASP.NET Core and React to the table. My team at Web Crest is focused on transforming old systems into contemporary, efficient solutions while keeping critical functionalities intact. This specific niche has been my forte for several years, and we have a proven track record of reliable, scalable output. Moreover, our skills extend far beyond just coding. We're well-versed in working with cloud technologies like AWS, Azure, and Google Cloud - a plus for your app modernisation project. Our vast skill set also means we can address any potential challenges you might face during this transformation process including any database or API-related issues. Lastly, communication is key to the success of remote projects. I want to assure you that at Web Crest, we have a streamlined approach to project management where our clients are kept in the loop in real-time and receive timely responses to all queries. With us on board, not only will your project benefit from our solid development skills but also from our excellent collaboration and client communication track record.
$1,500 USD in 7 days
3.0
3.0

hi, i have reviewed the details of your project. i have solid experience with c sharp, asp.net, legacy .net framework, asp.net core, react, sql, and rest apis, including working with existing codebases and modernization projects. i can maintain your legacy web forms, mvc, or wcf applications while building and improving asp.net core services and react features. i will focus on clean code, reliable api development, database work, testing, production issue fixing, and gradual modernization without disrupting existing systems. can we schedule a quick meeting to discuss the project in detail. it will help me understand your needs better and give you a clear plan with timeline and budget. i will also share my portfolio during the chat. mughiraa
$2,250 USD in 7 days
3.1
3.1

I can work across your legacy .NET Framework applications and modern ASP.NET Core services without treating the existing codebase as something that needs to be replaced immediately. I’m comfortable maintaining legacy Web Forms/MVC/WCF systems, building REST APIs, working with SQL databases, and developing React interfaces with clean component architecture. I can also handle modernization work where it makes sense, including refactoring legacy code, moving functionality toward ASP.NET Core, improving architecture and resolving production issues across the stack. I work with Git-based workflows, testing and clear technical documentation. I’m based in Pakistan and available for a long-term full-time remote role. I’d be happy to start by reviewing the current architecture and taking on a small existing task to demonstrate how I work.
$2,250 USD in 7 days
2.9
2.9

I’ve spent the last three years migrating legacy .NET Framework apps to .NET 6+ and maintaining Web Forms/MVC stacks, so this is straightforward. I’ll start with a codebase inventory—identify WCF endpoints, Web Forms pages, and SQL Server schemas—then set up parallel .NET 6 services for core APIs. Frontend work will involve React hooks, Redux Toolkit, and TypeScript, with strict ESLint/Prettier rules to enforce maintainability. For modernization, I’ll refactor legacy Web Forms into Razor Pages, extract reusable services, and push migrations to .NET 8 in stages to avoid downtime. SQL Server performance tuning will include query store and index optimization. I’ll use GitFlow with pre-commit hooks for enforced testing. Available now. Thanks, Andrii.
$2,250 USD in 30 days
2.3
2.3

Hi There!!! i understand that you are looking for a full time full stack developer in Pakistan to maintain and modernize your legacy dot net applications, build asp dot net core services, and develop react front end features. Services based on your requirements: * Legacy dot net framework application maintenance and refactoring * Modern asp dot net core api and backend service development * Interactive web interface development using react and typescript * Relational database management and sql server optimization * System modernization and migration assistance Let us connect in chat to discuss your current project architecture and how we can work together smoothly. Best Regards, Hussain Ahmed
$1,500 USD in 10 days
1.5
1.5

Hi, This role needs someone comfortable working between legacy .NET systems and newer React/ASP.NET Core services without disrupting existing functionality. I can help maintain the current platform, troubleshoot production issues, build APIs and React features, and gradually modernize older components where it makes sense. I have 13+ years of full-stack development experience across C#, .NET, React, APIs, databases, cloud systems, and SaaS applications. I’m comfortable joining an existing codebase, understanding unfamiliar systems quickly, and taking ownership of work independently. The $1,500–$2,000/month range works for me depending on the expected full-time hours and responsibilities. Let's connect and get started soon. Best regards, Binaya T.
$1,500 USD in 3 days
0.0
0.0

Hi there, I’d love to help maintain and modernize your platform. I’ve worked across full-stack .NET environments, including legacy codebases, ASP.NET Core services, React interfaces, SQL-backed systems, and production troubleshooting. What stands out here is the mix of stability and modernization , exactly the kind of work I enjoy. I can move comfortably between old and new code, improve maintainability, build clean React features, and help refactor legacy pieces toward a stronger architecture. I’m also used to working independently, reviewing code carefully, and collaborating closely with product and engineering teams to deliver reliable features. If you need someone who can keep critical systems running while steadily improving them, I’d be excited to contribute. Best, Panagiotis
$2,500 USD in 6 days
0.0
0.0

With over 5 years of professional experience in C#/.NET development, including a proficient background with both legacy .NET Frameworks and modern ASP.NET Core, I'm well-suited for maintaining, modernizing, and extending your software platform. I have garnered significant exposure to SQL Server and other relational databases, ensuring a solid foundation for handling data within your application. My abilities extend beyond the backend as I possess expert-level skills in working extensively with React, building UIs that are responsive and maintainable. I take pride in my problem-solving capabilities and I am just as comfortable working independently across unfamiliar codebases as I am collaborating with diverse teams. Having delivered clean, well-tested code across numerous projects, my experience aligns well with the need to rearrange legacy codes, migrate systems to .NET Core/5+, and improve overall architecture. Lastly, my expertise extends to building scalable and maintainable architectures ensuring the security and optimization of backend systems. With strong skills in Git, GitHub and Agile development workflows along with familiarity with CI/CD pipelines, my pragmatic approach to development will provide value-added support to your team's efforts to enhance feature development and resolve any production challenges that arise.
$2,000 USD in 20 days
0.0
0.0

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