.NET Web API — New Feature With Clean Architecture & Swagger | From $299
Need a new REST controller, a background service, or an integration with a third-party API in your ASP.NET Core application? Our .NET developers deliver clean, tested C# code — with proper dependency injection, validation, error handling, and Swagger docs — as a pull request ready for your review.
New feature or endpoint for your ASP.NET Core application. Clean architecture, Entity Framework integration, Swagger documentation. Integrates with your existing codebase.
"Senior engineers who actually deliver what they promise. Rare."
Thomas K., IT Manager · Austria
- ✓New endpoint/feature development
- ✓Clean architecture (controllers, services, repositories)
- ✓Entity Framework Core integration
- ✓Swagger documentation + integration tests
We'll confirm the exact price within 2 hours and send a PayPal invoice
Deliverables Included
Ready to Get Started?
New feature or endpoint for your ASP.NET Core application. Clean architecture, Entity Framework integration, Swagger documentation. Integrates with your existing codebase.
Who This Service Is For
How It Works
Order & Invoice
Day 1Place your order through PayPal or request an invoice. We send a detailed invoice within 1 business day.
Service Agreement
Day 1–2We prepare and sign a Service Agreement covering scope of work, deliverables, timeline, NDA, and warranty terms. Available for companies and individuals.
Execution & Delivery
Day 3–7A senior engineer performs the work per the agreed scope. You receive deliverables with documentation and a quality-check report.
Review & Warranty
14 days after deliveryReview the deliverables. Anything needs adjustment — we fix it within the 14-day warranty period at no extra cost.
Technologies We Use
Why .NET Web API Development Matters for Your Business
Building Enterprise-Grade APIs with .NET: Who Needs Professional Web API Development and Why Architecture Decisions Define Success
Learn why .NET is the natural choice for enterprise APIs and how proper architecture prevents costly technical debt.
Read the Full GuideWhat Our Clients Say
"Senior engineers who actually deliver what they promise. Fixed price, fixed timeline, thorough documentation. Rare combination."
"Worked with 4 agencies before finding Optimum Web. First team that delivered exactly what the scope said, on time."
"The 14-day warranty is real. Had a small follow-up question and it was handled same day, no extra charge."
Frequently Asked Questions
Yes. Before any work begins, we sign a Service Agreement covering: scope of work and deliverables, timeline and milestones, NDA (confidentiality), intellectual property rights, warranty terms, and payment schedule. We work with both companies (B2B) and individual clients. The agreement protects both parties and ensures clear expectations — included in every service at no extra cost.
We work with .NET 6, 7, and 8. For new code, we use .NET 8 (current LTS). We also maintain legacy .NET Framework 4.x projects if needed.
Yes — we review your project structure, existing patterns (Clean Architecture, MVC, Minimal API), and coding conventions, then add the feature in a consistent style.
Yes. Azure Blob Storage, Azure Service Bus, Azure AD/Entra ID, and Azure Functions integration is in scope. Add a note in your order.
Unit tests with xUnit or NUnit are always included. Integration tests with TestContainers.NET can be added as extended scope.
Yes. SignalR hub setup for real-time notifications, live data updates, or chat features can be included as part of this service. Specify your requirements during consultation.
This service includes a 14-day warranty. If anything doesn't work as specified after delivery — we fix it at no extra cost. No questions asked.
A senior engineer with 5+ years of hands-on experience. We never assign junior staff or subcontractors to fixed-price services.
Click 'Order Now', complete the secure PayPal payment, and we'll contact you within 24 hours to confirm scope and collect access details.
DIY vs Professional IT Services
| Feature | DIY | Professional (from $299) |
|---|---|---|
| Time to complete | ✗Hours to days | ✓Per agreed delivery window |
| Quality assurance | ✗Self-tested only | ✓Senior engineer review |
| Risk of errors | ✗High without experience | ✓Production-tested methods |
| Documentation | ✗Rarely included | ✓Full handoff documentation |
| Ongoing support | ✗You're on your own | ✓14-day warranty period |
| Warranty | ✗No safety net | ✓14-day fix guarantee |
You Might Also Need
.NET & Entity Framework Core Performance Optimization
N+1 queries, slow EF Core queries, memory bloat — diagnosed and optimized.
.NET Azure Integration — Blob Storage, Service Bus & Azure AD
Connect your ASP.NET Core app to Azure services — clean, production-ready integration.
Setup CI/CD Pipeline — GitHub Actions, GitLab CI or Bitbucket
Automated build, test, and deploy pipeline configured for your repository.
.NET Web API Development — Feature Addition or New Endpoint — from $299, 5–7 day Delivery
Senior engineers only. Fixed price. 14-day warranty. No surprises.
We'll confirm the exact price within 2 hours and send a PayPal invoice
Or email us directly: [email protected]