You will get Fix ASP.NET Core API Issues (JWT, Errors, SQL Performance)
Project details
If your ASP.NET Core API is slow, broken, or throwing errors — I can help fix it quickly and reliably.
I specialize in debugging and improving backend systems, especially in .NET applications.
I can help you with:
✔ JWT / authentication issues (401, 403 errors)
✔ API bugs, crashes, or unexpected behavior
✔ SQL performance problems (slow queries, timeouts)
✔ Fixing and improving existing backend code
With 5+ years of experience in FinTech and high-traffic systems, I focus on delivering clean, scalable, and long-term solutions — not quick patches.
Whether it's a small fix or a critical issue, I’ll identify the root cause and resolve it efficiently.
Send me a message before ordering so I can review your issue and guide you properly.
I specialize in debugging and improving backend systems, especially in .NET applications.
I can help you with:
✔ JWT / authentication issues (401, 403 errors)
✔ API bugs, crashes, or unexpected behavior
✔ SQL performance problems (slow queries, timeouts)
✔ Fixing and improving existing backend code
With 5+ years of experience in FinTech and high-traffic systems, I focus on delivering clean, scalable, and long-term solutions — not quick patches.
Whether it's a small fix or a critical issue, I’ll identify the root cause and resolve it efficiently.
Send me a message before ordering so I can review your issue and guide you properly.
Programming Languages
HTML & CSS, ASP.NET, C#Coding Expertise
Cross Browser & Device Compatibility, Performance Optimization, DesignWhat's included
| Service Tiers |
Starter
$15
|
Standard
$35
|
Advanced
$75
|
|---|---|---|---|
| Delivery Time | 1 day | 2 days | 3 days |
Number of Revisions | 1 | 2 | 3 |
Bug Investigation | |||
Fix Documentation | |||
Detailed Code Comments |
Frequently asked questions
About Nazmul
.NET Developer | Scalable APIs & Azure | Optimized 1.5M+ User System
London, United Kingdom - 2:56 pm local time
If your API is slow, throwing errors, or hard to maintain, I can fix it quickly.
If you are struggling with:
✔ JWT / OAuth issues (401/403 errors)
✔ Slow SQL queries or high API latency
✔ Legacy code that’s hard to scale
✔ Building a clean, scalable backend from scratch
⚡I focus on quickly identifying root causes and delivering efficient solutions.
💡 Why hire me?
* Worked on systems serving 1.5M+ users (80% faster processing)
* Improved backend performance by 40% through SQL optimization
* Expert in Clean Architecture, CQRS & scalable design
💼 Whether it’s a small bug fix or a full system build — I’m happy to help.
🛠 Tech Stack:
C#, .NET 8, ASP.NET Core, SQL Server, EF Core, Dapper, Azure, Angular
📩 Send me a message — I’ll quickly review your problem and suggest the best solution.
Steps for completing your project
After purchasing the project, send requirements so Nazmul can start the project.
Delivery time starts when Nazmul receives requirements from you.
Nazmul works on your project following the steps below.
Revisions may occur after the delivery date.
Analyze the issue
Review your code, logs, and error details to identify the root cause.
Fix the problem
Apply a clean and reliable solution to resolve the issue.