We are looking for an experienced .NET developer to migrate our existing monolithic RESTful API from .NET Core 2.2 to .NET 8. The API serves both mobile and web applications and is built with the following stack:
✅ .NET Core (to be migrated to .NET 8)
✅ PostgreSQL (Database)
✅ JSON-based API responses
✅ Entity Framework Core
✅ Authentication & Authorization (JWT, OAuth)
✅ Dependency Injection & Middleware
✅ Logging & Monitoring (log4net)
Project Scope & Requirements:
- Migrate from .NET Core 2.2 to .NET 8 while maintaining existing functionality.
- Ensure all 58 controllers function correctly after migration.
- 10 controllers are more complex (custom business logic), others are standard CRUD operations.
- Optimize and modernize the code where it makes sense, but all changes should be discussed in advance.
- Refactor deprecated methods and update dependencies as needed.
- Testing & Validation We have all necessary API request/response samples in Insomnia for easy testing.
- Results from the migrated API must match the current API.
Documentation:
- Well-commented and structured code.
- Clear documentation on changes made during migration.
- Performance & Security Considerations - Ensure no degradation in API performance.
- Apply best practices for security (e.g., improved authentication, HTTPS, rate limiting).
Who We’re Looking For:
- Experience in .NET Core & .NET 8 (hands-on migration experience preferred).
- Strong PostgreSQL & Entity Framework Core skills.
- Knowledge of RESTful API best practices and JSON handling.
- Familiarity with API authentication mechanisms (JWT, OAuth).
- Good understanding of asynchronous programming (async/await).
- Experience with testing tools (e.g., xUnit, NUnit, Postman/Insomnia).
- Ability to write clean, maintainable, and well-documented code.
- Strong communication skills (must be open to discussions about optimizations).
Timeline & Quality Expectations:
- No rush – quality is more important than speed.
- The project is complete when:
Code is fully migrated and well written.
- Tests pass (validated via Insomnia).
- Documentation is provided.
Any optimizations are agreed upon in advance.
- Using ChatGPT for coding is allowed, but only when reasonable (no blind AI-generated code).
Hello,
I understand that you're looking to migrate your existing RESTful API from .NET Core 2.2 to .NET 8. I'll ensure a smooth transition while keeping all 58 controllers functioning correctly. For the more complex controllers, I will work closely with you to maintain the business logic and to discuss any necessary optimizations. I will pay special attention to refactoring deprecated methods, updating dependencies, and validating the results against your current API using the provided Insomnia samples. Moreover, I’ll produce well-structured code, along with clear documentation on all changes and the performance and security measures taken.
What specific performance improvements or security measures do you expect to see after the migration?
Thanks,
Muhammad Awais
Dear Sir,
We have extensive exposure to .NET Core and .NET related technologies.
We have more than 20 years of experience in handling .NET related web application.
In case you need any clarifications, please feel free to contact us.
Thanking you and best reagrds.
Sanjay
In a previous project, I faced challenges with API performance after migrating from .NET Core 2.1 to 3.1, specifically with asynchronous tasks causing delays. I understand your need to migrate from .NET Core 2.2 to .NET 8 while preserving existing functionality. I have experience ensuring all controllers work correctly, including those with complex business logic. I can optimize the code and update dependencies with clear documentation on all changes. I’ll ensure security best practices are in place and the API performance remains top-notch.
Hi there,
I’m really interested in helping with your .NET Core 2.2 to .NET 8 migration. With hands-on experience in .NET Core and recent projects involving .NET 8 upgrades, I’m confident in handling both standard CRUD operations and complex business logic.
My background in PostgreSQL and Entity Framework Core ensures smooth database transitions, and I always follow best practices for security (JWT, OAuth, HTTPS) and performance optimization.
I take a careful, structured approach to migrations—starting with dependency updates, refactoring deprecated methods, and ensuring backward compatibility where necessary.
Every change is tested thoroughly using tools like Insomnia and xUnit, and I document everything clearly so future maintenance is seamless.
also prioritize open communication, discussing optimizations before making any modifications.
Looking forward to working together.
Cheers,
Roman
HELLO, I HAVE WORKED ON SIMILAR PROJECTS AND CAN PROVIDE EXAMPLES.
I have read your requirements carefully and can confidently handle this project.
With over 4 years of experience in .NET development, I specialize in migrating monolithic APIs, ensuring seamless upgrades while maintaining performance and security.
I will migrate your .NET Core 2.2 API to .NET 8, refactor deprecated methods, update dependencies, and ensure all 58 controllers function correctly with no loss of functionality.
My expertise in Entity Framework Core, PostgreSQL, JWT/OAuth authentication, and API security best practices ensures a smooth transition with optimized performance and maintainable code.
Proposed Working Flow:
Migrate .NET Core 2.2 API to .NET 8, updating dependencies and resolving deprecated methods.
Ensure all 58 controllers work correctly, with a focus on 10 complex business logic controllers.
Optimize and modernize code where needed while maintaining existing functionality.
Implement best practices for security, logging, and performance optimization.
Validate migration through extensive testing (xUnit, Insomnia) and provide detailed documentation.
Let’s connect and ensure a seamless transition to .NET 8!
Julian
Hello,
How r u doing?
I have gone through the project and i believe that i can handle it well having experience related to Software Testing, PostgreSQL, .NET Core, OAuth and RESTful API. Please have a look at my profile to have an idea of my previous work: https://www.freelancer.com/u/ayesha0124
Regards,
Ayesha
Hello! I see you're looking to migrate your RESTful API from .NET Core 2.2 to .NET 8 while maintaining its functionality. This is crucial for ensuring a seamless experience for both your mobile and web applications.
Here’s how I would approach this migration:
1. **Assessment**: Review the current API structure and identify areas for optimization.
2. **Migration**: Upgrade to .NET 8, ensuring all 58 controllers operate correctly, including the 10 with custom business logic.
3. **Refactoring**: Address deprecated methods and update dependencies while discussing any optimizations with you.
4. **Testing**: Utilize your existing Insomnia samples to validate that the migrated API matches the current functionality.
5. **Documentation**: Provide clear comments and documentation on the migration process and changes made.
With over 200 successful projects, I have extensive experience in .NET migrations and have worked with complex API structures, ensuring performance and security best practices. For example, I recently migrated a large-scale API for a major client, resulting in a 30% performance improvement post-migration.
I’m excited about the opportunity to work on this project and ensure a smooth transition. If you have any questions or would like to discuss next steps, please let me know!
Hi,
***** .Net expert*****
I have more than 15 years of experience in the development
As I am an expert, I can build it according to your requirements.
Because I have a lot of experience in these fields, I can build your project as soon as possible.
I offer excellent software quality work and provide the best support for your project.
If you give me this job, I will do my best to finish your job by your timeline.
If you want to see my past works, I can show you my past works right now.
Ready to discuss this with you about the task now.
Thank you for the reading.
Dear client, I am very exciting your project. I have over 5 years experience with ASP.NET, .NET core web developing. So I am familiar with PostgreSQL, OAuth, Restful API and testing. Recently I worked with one online learning system which was written ASP.NET and React.js. master.letsuserdata.com. From my experience, I am sure you are fully satisfied with my work. I hope your response sincerely. Best regards.
Being a seasoned full stack developer with a comprehensive understanding of RESTful API, my core competency in both .NET Core and .NET 8 can be a game changer for your monolithic migration project. I have successfully led similar migration projects in the past, ensuring not only seamless transition from deprecated versions to the latest ones, but also preserving the same functionality and reducing the risk of regressions.
Let's work together to create streamlined experiences for your mobile and web app users!
Hello There,
I have extensive experience in .NET Core and have successfully migrated legacy applications to modern .NET versions. I can efficiently migrate your API from .NET Core 2.2 to .NET 8 while ensuring functionality, performance, and security remain intact.
I will ensure all controllers function correctly, update deprecated methods, and optimize where necessary—all while maintaining transparency on changes. Let’s discuss further to align on expectations.
Looking forward to collaborating!
Best regards,
Deo
Dear Sir/Madam,
I am top 1% .Net Full Stack Developer at Freelancer with 13 years+ experience on .Net, ASP.NET Core, C#, MVC, Blazor, WCF, API, SQL Server, Angular, Bootstrap, HTML5, Telerik Controls, Payment Gateway Integration etc & ensuring high-quality results.
Let’s discuss your project details and how I can help you achieve your goals.
Waiting for your positive reply.
Best Regards,
Milan Sahu
Hello,
Can we discuss the project details over chat?
I am MS full stack developer having expertise in developing web, desktop application and I think I can manage this project well.
I can share my project examples with you.
I do have working experience on Sharepoint and created various LogicApps on Azure in order to automate some of the process as per requirements. PowerApps has similar way to work with LogicApps but platform is different only.
I do have working experience on .NET core api with Angular application.
- Implementation of D3 Js library in Angular application.
--Sparkle chart
--Donut Chart
--Pie Chart
--Radar Chart
--Stacked Bar Chart
--Scatter Graph
I do have working experience on Salesforce Apex programming by performing following tasks.
- Triggers to post data back on MSSQL server by using .NET Apis (written myself as well).
- Salesforce Visual force pages to fetch data from .NET based Apis to show data from MSSQL database.
- creating/updating contacts, Accounts standard objects and custom objects data via .NET Apis.
- Done some RND for Salesforce flows for some automation but due to limitations from custom objects did not used them well.
Hope to hear from you soon.
Thanks
Hello! Saw your post and I’d love to help!
To migrate your .NET Core 2.2 API to .NET 8, I’d update all 58 controllers—keeping the business logic untouched where needed, while modernizing deprecated methods, packages, and middleware to align with the .NET 8 lifecycle. I’ll also review and update Entity Framework Core patterns, refresh JWT/OAuth setup if needed, and make sure async/await is cleanly handled throughout. Logging via log4net will be preserved or enhanced with better observability practices if needed.
I’ve led full-stack .NET migrations before, balancing safety and performance while writing clear commit-by-commit documentation. Everything will be tested against your Insomnia samples to ensure full parity.
Would love to chat through the architecture and dive in. Let’s connect when you’re ready!
Thanks for your time.
Regards, Denis.
Hello lxcoders,
I have a clear understanding of your requirement to migrate your existing monolithic RESTful API from .NET Core 2.2 to .NET 8, maintaining all existing functionality. My approach involves a meticulous migration process, ensuring that all 58 controllers, including the 10 more complex ones with custom business logic, function correctly post-migration. I will optimize and modernize the code where necessary, with all changes discussed beforehand to align with your expectations.
With my extensive expertise in PostgreSQL and hands-on experience in .NET Core & .NET 8 migrations, I am well-equipped to handle this project effectively. I have a strong background in Entity Framework Core, RESTful API best practices, and JSON handling. Additionally, my commitment to clear communication and collaboration ensures a smooth workflow and successful project delivery.
Best regards,
Justin
Hello, I have been working with .NET development for 7 years now. I've checked your project description carefully and I am sure that I can complete this project 100% perfectly sure to satisfy your requirement. I'd like to have a brief chat, call to discuss further details about your project soon.
Looking forward to working with you together on this project.
Thanks!
Hhi I am experienced in this and I can start right now but i have few doubts and questions lets have a quick chat and get it started waiting for your replyyy ! r
Hello there,
I’ve read your project description, and it sounds like you’re looking for a reliable .NET developer to migrate your existing .NET Core 2.2 RESTful API to .NET 8 while preserving all functionality and improving the codebase where appropriate.
I’m a Full Stack Web Developer with 6+ years of experience, and I’ve successfully handled similar migrations involving .NET Core, Entity Framework, and PostgreSQL. I’m confident working with complex controllers, async/await patterns, authentication mechanisms (JWT, OAuth), and performance tuning. Clean, maintainable, and well-documented code is a top priority in every project I take on.
What really stood out is your focus on quality over speed—that’s how I like to work too. I’d love to jump in, ensure a smooth, well-tested migration, and collaborate closely with you on any improvements.
I am looking forward to the chance of working together.
Best regards,
Billy Bryan
I am eager to discuss the .NET Core 2.2 to .NET 8 migration project and how my expertise can ensure a smooth transition. As you mentioned, the API serves both mobile and web applications with complex controllers, standard CRUD operations, and reliance on PostgreSQL, Entity Framework Core, and JWT for authentication. My experience with similar migrations, particularly with .NET Core and FastAPI, makes me well-suited to tackle this challenge.
My technical skills align perfectly with your requirements, including expertise in RESTful API best practices, JSON handling, and a thorough understanding of asynchronous programming. I am confident that I can deliver a comprehensive solution that meets your quality expectations while prioritizing code readability and maintainability.
Please send me a direct message from my profile immediately so we can discuss the project further.
Hi there. With a strong backend in .NET Core, I can migrate our existing monolithic RESTful API from .NET Core 2.2 to .NET 8. Let's have a brief discussion and get started. Cheers, Tayo.
