.NET Migration Services
Migrate ASP.NET WebForms, MVC and .NET Framework applications to modern .NET 10, safely and step by step.
Modernise Your Legacy .NET Applications
Three Circle migrates legacy .NET applications to modern, supported .NET without disrupting your business, so your software becomes faster, more secure and cheaper to run.
Rebuild WebForms pages on modern ASP.NET Core while keeping your business logic.
Upgrade libraries, services and APIs to the current long-term support release.
Incremental migration so your users keep working throughout.
Modernise Your .NET Applications
We analyse your code, dependencies and risks, then give you a clear migration plan and estimate.
Move off unsupported frameworks and get regular security updates again.
Modern .NET runs the same workloads faster on fewer servers.
Containers, Linux hosting and Azure services become available after migration.
Regular demos, progress reports and one point of contact.
Monitoring, optimisation and ongoing maintenance after go-live.
Hire .NET Migration Experts
Work with experienced ASP.NET Core developers who understand both legacy .NET and the modern platform, and who will plan your migration around your business priorities.
What We Migrate
From small internal tools to large customer-facing platforms, these are the most common .NET migrations we deliver:
WebForms and MVC Applications
Customer portals, intranets and line-of-business applications moved to ASP.NET Core.
APIs and Services
WCF, ASMX and Web API services modernised as REST or gRPC APIs.
Hosting and Databases
IIS servers moved to Azure or containers, and SQL Server upgraded or moved to Azure SQL.
Why Choose Three Circle for .NET Migration?
Three Circle is an ASP.NET development company based in Texas and the UK. We plan migrations carefully, communicate clearly and keep your business running while your software is modernised.
Deep .NET Expertise:
Our developers work with both legacy .NET and modern ASP.NET Core every day.
Incremental, Low-Risk Approach:
We migrate in small, tested steps instead of risky rewrites.
Ongoing Support:
We stay with you after go-live for monitoring, fixes and improvements.
End-to-End Service:
Assessment, migration, testing, cloud hosting and support from one team.
Transparent Communication:
Regular demos, clear reports and honest estimates.
Reliable Delivery
Clear milestones and efficient workflows keep your migration on schedule.
.NET Migration Services We Offer
Three Circle provides .NET migration services that move legacy ASP.NET WebForms, ASP.NET MVC and .NET Framework applications to modern .NET (.NET 10, the current long-term support release). We migrate step by step, so your application keeps running while it becomes faster, more secure, cheaper to host and easier to maintain. Our team has built production systems on ASP.NET Core for years, as you can see on our ASP.NET development page.
ASP.NET WebForms to ASP.NET Core
Rebuild WebForms pages with Razor Pages, Blazor or React while reusing your proven business logic. Read our WebForms to ASP.NET Core migration guide.
ASP.NET MVC to ASP.NET Core
Upgrade controllers, views, authentication and configuration to the modern ASP.NET Core pipeline.
.NET Framework to .NET 10
Move class libraries, services and background jobs from .NET Framework 4.x to cross-platform .NET.
.NET 6, 7 and 8 Upgrades
.NET 6 and 7 are already out of support and .NET 8 support ends in November 2026. We upgrade you to .NET 10 LTS with minimal changes.
WCF and Web Services Modernisation
Replace WCF and ASMX services with secure REST APIs or gRPC.
Cloud Migration to Azure
Move from on-premise IIS servers to Azure App Service, containers or AWS. See our cloud development services.
Why Migrate from .NET Framework Now
- No new features: .NET Framework 4.8 is the final version; it only receives security fixes and runs on Windows only.
- Support deadlines: .NET 6 and .NET 7 are already unsupported, and .NET 8 support ends in November 2026. Unsupported versions stop receiving security patches.
- Performance: modern .NET is significantly faster, so the same application needs fewer servers.
- Lower hosting costs: run on Linux, containers and cheaper cloud plans.
- Security and compliance: current frameworks, libraries and authentication standards.
- Easier hiring: developers want to work with modern .NET, not legacy WebForms.
Our .NET Migration Process
- Free assessment: we analyse your code, dependencies and hosting with tools such as the .NET Upgrade Assistant and give you a clear migration plan and estimate.
- Migration plan: we choose the safest path, usually an incremental migration rather than a risky “big bang” rewrite.
- Pilot: we migrate one module first to prove the approach.
- Incremental migration: old and new applications run side by side behind a proxy (YARP) while features move across.
- Testing: automated regression, performance and security testing at every step.
- Cut-over and support: switch off the old system, monitor closely and keep improving.
How We Reduce Migration Risk
- No big-bang releases: features move in small, tested steps.
- Business continuity: your users keep working while we migrate.
- Data integrity: database changes are scripted, tested and reversible.
- Automated tests: we add tests around critical features before changing them.
- Rollback plan: every release can be rolled back quickly if needed.
- Clear reporting: regular demos and progress updates.
Real .NET Projects We Have Built
Our team builds and runs production applications on modern ASP.NET Core every day:
HRM Platform and Mobile App Used by 5,000+ Employees
For a growing organisation we built a complete HR management platform: a web admin dashboard (React and Angular) for employee records, attendance and office operations, a Flutter mobile app for attendance and leave requests, and an ASP.NET Core API behind both. Result: more than 5,000 active users.
Optimized Strength: AI-Powered Fitness App with 1,000+ Downloads
Optimized Strength is a cross-platform fitness app built with Flutter for iOS and Android and a secure ASP.NET Core back end. It gives users more than 1,300 exercises, personalised AI coaching and progress tracking with visual charts. Result: 1,000+ downloads.
LuvInvite: Digital Invitation Platform on Flutter, .NET and Azure
LuvInvite lets users design custom digital invitations from elegant templates for weddings, birthdays and events, share them and manage guest registries. We built the web and mobile apps with Flutter, a .NET back end and Microsoft Azure cloud hosting.
Want results like these? Tell us about your .NET migration project and get a free consultation.
Our .NET Migration Technology Stack
- Target platform: .NET 10 (LTS), ASP.NET Core, C#
- User interface: Razor Pages, Blazor, ASP.NET Core MVC, React or Angular
- Data: Entity Framework Core, SQL Server, Azure SQL, PostgreSQL
- Migration tooling: .NET Upgrade Assistant, YARP reverse proxy, API analyzers
- Cloud and DevOps: Azure App Service, Docker, Kubernetes, GitHub Actions, Azure DevOps
.NET Migration Engagement Models and Pricing
Choose the way of working that fits your budget and timeline:
Fixed-Price Projects
Best for MVPs and projects with a clear scope. You agree on price, timeline and features before development starts.
Time and Materials
Flexible for products that will evolve. You pay for actual development time and can change priorities after every sprint.
Hire Dedicated .NET Developers
Add experienced .NET developers, designers and QA engineers to your team on a monthly basis for long-term development.
Want a quick budget? Use our app development cost calculator or request a free estimate.
Ready to Modernise Your .NET Application?
Get a free .NET migration assessment and a clear plan to move your application to modern, supported .NET.
- FAQs
Frequently Asked Questions
.NET migration services move applications built on older technologies, such as ASP.NET WebForms, ASP.NET MVC or .NET Framework, to modern .NET, improving performance, security and maintainability.
For most active business applications, yes. .NET Framework receives no new features, while .NET 10 is faster, cross-platform, cheaper to host and supported long term.
Small applications can take a few weeks, while large enterprise systems take several months. Our free assessment gives you a clear timeline.
Cost depends on the size of the codebase, dependencies and testing needs. Read our ASP.NET development cost guide or request a free assessment.
Usually, yes. We use an incremental approach where the old and new applications run side by side, so users keep working while features move across.
WebForms pages are rebuilt using Razor Pages, Blazor or a modern front end such as React, while we reuse and improve your existing business logic and database.
Yes. Many clients combine migration with a move to Azure App Service or containers to reduce hosting costs.
Microsoft support for .NET 8 ends in November 2026. After that it no longer receives security updates, so we recommend upgrading to .NET 10, the current long-term support release.