.Net Application Migration Services

Why Migrate Legacy .Net Applications?

Legacy .Net systems accumulate cost over time: slower deployments, mounting technical debt, and architecture that wasn't built for cloud or modern integrations. The longer .Net app migration is deferred, the more expensive it becomes to add features, maintain compliance, or scale under load.

• Outdated .Net Framework versions lose Microsoft support, creating security and compliance exposure
• Teams working on legacy codebases spend more time on maintenance than on new product capabilities
• Monolithic architecture limits the ability to deploy independently, test reliably, or scale individual components

Our .Net Migration and Modernization Services

.Net Application Migration Services

We migrate existing .Net applications to modern architecture with controlled scope and phased delivery. Your system stays in production while we move components incrementally.

ASP.Net Migration Services

We migrate ASP.Net Web Forms and legacy MVC applications to current .Net with updated routing, middleware, and component structure. Existing business logic is preserved; only what limits the architecture is replaced.

.Net Core Migration Services

We move applications from .Net Framework to .Net Core and modern .Net, resolving API compatibility gaps and restructuring where needed. The result is a cross-platform, cloud-ready codebase that runs on current infrastructure.

.Net Framework Upgrade Services

We provide .Net migration and up-gradation services for applications running on .Net Framework 2.0 through 4.8: updating dependencies, removing deprecated APIs, and validating each change against your existing test coverage. No big-bang rewrites.

Cloud Migration for .Net Applications

We migrate .Net workloads to AWS or Azure using lift-and-shift, replatforming, or targeted refactoring based on your architecture. Phased delivery keeps compliance and uptime constraints in scope from day one.

Ready to Scope Your .Net Migration?

Get a clear picture of what your migration requires before committing budget. We deliver a written assessment with architecture analysis, risks, and phased estimates.

Request a migration assessment →

Types of .Net Applications We Migrate

Enterprise Applications

We migrate business-critical enterprise applications built on legacy .Net stacks, including those running across multiple environments or integrated with internal systems. Migration scope is defined before any code changes begin.

SaaS Platforms

We migrate SaaS platforms to modern .Net with multi-tenant architecture, cloud hosting, and deployment pipelines that support continuous releases. One platform we migrated now processes daily loads that were impossible on the legacy stack.

CRM and ERP Systems

We migrate CRM and ERP systems by decoupling modules, updating data layers, and maintaining API compatibility so connected systems don't break during transition. Business workflows stay intact.

Customer Portals

We migrate customer-facing portals with attention to session management, authentication, and frontend integration. A healthcare portal migration we delivered extended a desktop application into a web portal without disrupting the existing system.

E-commerce Solutions

We migrate e-commerce platforms built on legacy .Net, updating payment integrations, catalog logic, and backend services while keeping storefronts live during the process.

Internal Business Applications

We migrate internal tools and line-of-business applications that teams depend on daily. Downtime risk is managed through feature flagging, parallel environments, and staged rollouts.

Legacy Technologies We Modernize

.Net Framework Applications

We migrate applications running on .Net Framework 2.0 through 4.8 to modern .Net, handling dependency resolution, configuration updates, and API replacements throughout.

ASP.Net Web Forms

We migrate Web Forms applications to Razor Pages or modern MVC by converting page lifecycle logic, state management, and server controls to current patterns.

ASP.Net MVC Applications

We migrate ASP.Net MVC applications to current .Net MVC or minimal API architecture, updating routing, dependency injection, and middleware to match modern conventions.

WCF Services

We migrate WCF services to gRPC, REST APIs, or CoreWCF depending on your integration requirements. Existing service contracts are mapped before migration begins.

Windows Services

We migrate Windows Services to .Net Worker Services or containerized background jobs that run on Linux and cloud environments without platform lock-in.

Monolithic Applications

We decompose monolithic .Net applications into modular or microservices architecture through incremental extraction. One module at a time, with each release tested and stable before the next phase begins.

Our .Net Migration Process

Application Assessment

Two weeks. We map your architecture, dependencies, integration points, data flows, and technical debt, then deliver a written output: risks, priorities, and phased estimates before any development starts.

Migration Planning

We define the migration path, phase sequence, and rollback approach based on your system's constraints. Budget and timeline are estimated per phase, not as a single project total.

Architecture Modernization

We design the target architecture before writing any migration code. This includes dependency structure, API design, cloud hosting approach, and the boundaries between legacy and modernized components.

Code Migration and Refactoring

We migrate code incrementally, resolving compatibility issues, updating patterns, and refactoring what no longer fits the target architecture. Code reviews and integration tests run at each step.

Quality Assurance and Testing

We build or extend automated test coverage across UI and API layers to validate each migration phase. On one enterprise migration, we built 5,000+ end-to-end scenarios running daily, achieving a 95% stable pass rate and cutting QA effort by 70%.

Deployment and Launch

We deploy migrated components to production using blue-green or canary strategies, with rollback procedures defined before each release. Downtime is avoided through parallel environments and feature flagging.

Post-Migration Support

We monitor stability, resolve edge cases, and track performance after launch. Support scope and duration are agreed upfront, not treated as an afterthought.

Benefits of .Net Migration

Enhanced Performance

One utility platform migration improved API response time by 15x and reduced crawler runtime by 100x through backend and database architecture improvements. A logistics invoicing migration delivered 40% faster releases after moving to automated deployments.

Improved Security

Modern .Net versions include active security patching, updated cryptography, and current authentication standards. Legacy .Net Framework versions past end-of-support no longer receive security updates from Microsoft.

Reduced Maintenance Costs

A database and infrastructure optimization during one .Net migration reduced hosting costs by 50% for the client. Maintenance costs fall when technical debt is removed and deployments become automated.

Greater Scalability

Modern .Net runs on Linux and containerized environments, which opens horizontal scaling options that weren't available on legacy Windows-only deployments. Cloud hosting on AWS or Azure adds auto-scaling to the picture.

Faster Release Cycles

A logistics platform migration we delivered produced 40% faster releases by moving from a legacy application server to modern infrastructure with automated deployments. CI/CD pipelines, automated testing, and modular architecture remove the manual steps that slow release cycles.

Industries We Serve

FinTech

We rebuilt a financial planning application toward component-oriented architecture on .Net 6, including a multi-tenant execution engine, while maintaining compatibility with existing .Net Framework components. The result: improved maintainability, faster development cycles, and reduced infrastructure overhead.

Healthcare

We extended a desktop healthcare application into a browser-accessible web portal using an API Gateway backend-for-frontend pattern, reducing integration risk while improving accessibility and user engagement. We've also extended mobile patient workflows with offline functionality and supported systems used in early cancer detection algorithms. Compliance requirements shape every decision in our healthcare .Net work.

Logistics and Transportation

A logistics invoicing system migration we delivered produced 40% faster releases and 30% fewer deployment errors after moving from a legacy application server to modern infrastructure with automated deployments.

Manufacturing

We deliver .Net backend systems for manufacturing operations: production monitoring, quality control integrations, and IoT-connected data workflows. Migration work in this sector prioritizes uptime given the dependency on continuous production.

Retail and E-commerce

We migrate .Net e-commerce platforms and backend services with attention to transaction integrity, catalog performance, and integration with payment and logistics systems.

SaaS and Technology

We migrated a Windows utility backend from legacy ASP.Net MVC to a Web API plus Angular architecture: database hosting costs dropped by 50%, API response time improved by 15x, and crawler runtime sped up by 100x. We've also supported multi-product SaaS ecosystems where backend services, APIs, and crawlers needed to stay live throughout migration.

Why Choose Techstack as Your .Net Migration Company

Experienced .Net Engineers

Techstack is a .Net application migration services development company with 12+ years of hands-on experience across .Net Framework, .Net Core, .Net 6/7, and current .Net. We've worked with C#, F#, ASP.Net, WCF, and Windows Services in production environments, not just greenfield builds.

Proven Migration Methodology

Assessment before plan, plan before code. Each phase is scoped independently and validated before the next begins. On one enterprise migration, this approach produced a 95% stable pass rate and cut QA effort by 70%.

Minimal Downtime Approach

We use parallel environments, feature flags, and incremental deployment to keep your application available during migration. Blue-green and canary releases are standard. Your users don't experience the transition.

Enterprise-Grade Security

Techstack is ISO/IEC 27001:2022 and ISO/IEC 27701:2019 certified, GDPR-compliant, and named to the Clutch 1000. Authentication updates, secrets management, and compliance validation are in scope from the start.

Flexible Engagement Models

We work as a dedicated migration team, staff augmentation to extend your existing engineers, or end-to-end project partner. All engagements run on Time and Materials billing so you pay for actual work done.

Technologies We Use

Languages: C#, F#, TypeScript, Python

.Net runtimes: .Net Framework 2.0–4.8, .Net Core 2.x–3.x, .Net 5/6/7/8

Web frameworks: ASP.Net Core, ASP.Net MVC, Minimal API, Razor Pages

Databases: MSSQL, PostgreSQL, MySQL, MongoDB, Redis

Cloud: AWS (Lambda, ECS, RDS, CodePipeline), Microsoft Azure (App Service, Azure DevOps, Functions)

CI/CD and DevOps: GitHub Actions, Azure DevOps, Jenkins, Terraform, Docker, Kubernetes

Testing: NUnit, xUnit, Moq, Selenium, SpecFlow, Fluent Assertions

What Our Clients Say

"Techstack Ltd kept the uptime and the customers happy. The team was highly competent, proactive, and efficient, excelling for their technical and thought leadership."
Mark Beare, Former VP of Research & Development, Corel Corporation — Clutch

"What I liked most about working with Techstack was their seamless teamwork and deep technical competence. Their experience in building world-class apps was evident in every phase of development, from ideation to execution. They collaborated with our team effortlessly, feeling like an extension of our own staff."
John Busch, Founder & CEO at ILIAD — GoodFirms

Engagement Models

Dedicated Team

We assemble a dedicated .Net migration team: engineers, QA, and DevOps specialists working full-time on your migration. You get delivery accountability and direct team access without managing the hiring process.

Staff Augmentation

Our .Net engineers join your existing team under your management. Specialists can be hired on full-time or part-time (0.25, 0.5, or 0.75 FTE) arrangements, and you pay only for actual hours worked.

End-to-End Migration Project

We manage the full migration lifecycle from assessment to post-launch support. This includes architecture planning, phased delivery, automated testing, deployment, and stabilization. Billed on Time and Materials based on actual work completed.

Ready to Start Your .Net Migration?

A migration that starts with a clear assessment costs less and delivers more than one that starts with assumptions. Get a written plan before any code changes.

Schedule your migration assessment →