You will get bugs fixed in your C# ASP.NET Core Web API
Rising Talent
Rising Talent
Project details
Are you facing bugs, unexpected errors, or performance issues in your C# / ASP.NET Core Web API?
I can help you investigate the problem, identify the root cause, and implement a clean and reliable fix without making unnecessary changes to your existing codebase.
I have 5 years of professional experience working with C# and .NET backend applications, including ASP.NET Core, Entity Framework Core, SQL Server, PostgreSQL, REST APIs, authentication, business logic, and enterprise systems.
I can help with:
• ASP.NET Core Web API errors
• Entity Framework Core issues
• SQL Server / PostgreSQL problems
• API request and response issues
• Business logic bugs
• Dependency Injection issues
• JWT authentication and authorization
• Validation and exception handling
• AutoMapper and object mapping
• API integrations
• Performance issues
• Existing .NET codebases
My approach is simple: reproduce the issue, investigate the root cause, implement a focused fix, and verify the result.
Please contact me before ordering if your issue is complex or the scope is unclear.
I can help you investigate the problem, identify the root cause, and implement a clean and reliable fix without making unnecessary changes to your existing codebase.
I have 5 years of professional experience working with C# and .NET backend applications, including ASP.NET Core, Entity Framework Core, SQL Server, PostgreSQL, REST APIs, authentication, business logic, and enterprise systems.
I can help with:
• ASP.NET Core Web API errors
• Entity Framework Core issues
• SQL Server / PostgreSQL problems
• API request and response issues
• Business logic bugs
• Dependency Injection issues
• JWT authentication and authorization
• Validation and exception handling
• AutoMapper and object mapping
• API integrations
• Performance issues
• Existing .NET codebases
My approach is simple: reproduce the issue, investigate the root cause, implement a focused fix, and verify the result.
Please contact me before ordering if your issue is complex or the scope is unclear.
Programming Languages
ASP.NET, C#Coding Expertise
Performance Optimization, SecurityWhat's included
| Service Tiers |
Starter
$20
|
Standard
$60
|
Advanced
$120
|
|---|---|---|---|
| Delivery Time | 1 day | 2 days | 3 days |
Number of Revisions | 1 | 2 | 2 |
Bug Investigation | |||
Fix Documentation | - | ||
Detailed Code Comments | - | - |
Optional add-ons
You can add these on the next page.
Additional Revision
+$15
Fix Documentation
+$20Frequently asked questions
About Phu
C# / ASP.NET Core Backend Developer | REST API | EF Core | Bug Fixing
Hanoi, Vietnam - 11:43 pm local time
I help clients build, maintain, troubleshoot, and improve .NET applications, especially when they need someone who can quickly understand an existing codebase and solve problems without introducing unnecessary complexity.
What I can help you with:
- Build REST APIs using ASP.NET Core
- Debug and fix existing C#/.NET applications
- Fix Entity Framework Core and database issues
- Design and optimize SQL Server/PostgreSQL queries
- Implement authentication and authorization with JWT
- Develop business logic and backend services
- Maintain and extend existing .NET codebases
- Refactor legacy or complex backend code
- Design database models and relationships
- Integrate third-party APIs and services
- Implement background jobs and scheduled processing
- Work with Microservices and distributed systems
- Dockerize and deploy .NET applications
Technologies I work with:
Backend
C#, .NET Core, .NET 8, .NET 9, ASP.NET Core, REST API, ABP Framework, Entity Framework Core, Dapper
Architecture
Clean Architecture, DDD, SOLID, Microservices, Repository Pattern, Dependency Injection
Database
SQL Server, PostgreSQL, Redis
Integration & Messaging
RabbitMQ, REST API, gRPC, Firebase Cloud Messaging
Background Processing & Workflow
Hangfire, Elsa Workflow, Camunda
Development Tools
Git, GitHub, GitLab, Swagger, Postman, Serilog
DevOps
Docker, Docker Compose, Linux, GitLab CI/CD, GitHub Actions, Jenkins, AWS EC2, AWS S3
I have worked on enterprise systems including investment portfolio management, business planning and approval systems, HR applications, e-invoice systems, reporting systems, and data-processing applications.
I’m comfortable joining an existing project, understanding its architecture, investigating issues independently, identifying root causes, and implementing focused solutions.
I’m currently building my reputation on Upwork, but I bring 5 years of professional .NET development experience. My goal is to build long-term trust here through reliable communication, clean implementation, and high-quality work.
If you have a C#/.NET backend issue, an API that needs fixing, or an existing application that needs maintenance or new functionality, feel free to contact me.
Steps for completing your project
After purchasing the project, send requirements so Phu can start the project.
Delivery time starts when Phu receives requirements from you.
Phu works on your project following the steps below.
Revisions may occur after the delivery date.
Review the issue and codebase
I will review the issue description, relevant source code, logs, configuration, and expected behavior to understand the current implementation.
Reproduce and identify the root cause
I will reproduce the issue and trace the API flow, business logic, database operations, and related components to identify the actual root cause.