.NET Software Development Services: .NET Development Company for Custom Applications

Updated September 2026 · Written and maintained by the Progression Agency strategy team

Progression Agency provides .NET software development services: web applications with ASP.NET Core, APIs, cloud services on Azure, desktop applications and modernization of older .NET Framework systems, for businesses that run on Microsoft technology. Dot net development services can mean a small API or a full migration, and however a brief spells it (dotnet development services is common), check which version the quote assumes. A dot net development company should state that in writing, because dot net development companies quoting on an older .NET Framework system are pricing different work from a new build on .NET 10. Our .NET developers cover software development in .NET across the full lifecycle, from design and build through testing, release and ongoing support, on new products and rescues of struggling ones.

What are .NET software development services?

.NET software development services design, build, integrate and maintain applications on Microsoft’s .NET platform: ASP.NET Core web apps and APIs, Blazor front ends, Windows desktop applications, background services and Azure cloud workloads, usually in C#.

Businesses choose .NET when their data lives in SQL Server, their identity in Microsoft Entra ID and their operations in Dynamics or Microsoft 365, because integration is native. See custom software development for platform-neutral projects.

.NET development services

Projects we are most often asked to build.

ASP.NET Core web application development

Customer portals, internal tools and SaaS products with role-based access and Entra ID sign-in. Custom .NET application development earns its keep when the process is peculiar to your company, such as approvals or pricing rules, and a packaged product would need constant workarounds. When the same portal also needs a native companion for phones, .NET MAUI app development lets one C# codebase target iOS and Android and share logic with the web back end.

Custom .NET APIs and integrations

REST and gRPC services that connect SQL Server, Dynamics 365, Microsoft 365 and third-party systems.

Azure cloud development

App Service, Azure Functions, Service Bus, Azure SQL and infrastructure as code with Bicep or Terraform.

Desktop application development

Windows applications in WPF or WinUI, and cross-platform desktop with .NET MAUI; see desktop application development.

.NET Framework to modern .NET migration

Assessment, incremental migration and modernization of older applications without a big-bang rewrite.

Maintenance and support

Security patching, LTS upgrades, performance work and monitoring on a monthly plan.

Assessment, incremental migration and modernization of older applications without a big-bang rewrite.

ASP.NET development services: which framework the quote covers

Most new work today means ASP.NET Core, the cross-platform, open-source framework, although plenty of live systems still run on the older ASP.NET tied to .NET Framework. Before you hire an ASP.NET development service company, ask which of the two it is quoting on and whether the plan moves one to the other.

ASP.NET application development services cover the server code, data access, sign-in and the interface, whether that interface is Blazor or a separate React or Angular front end. Whether an RFP spells it ASP dot NET development services or asks for a single ASP.NET development service such as an API, the scope question stays the same. An ASP.NET Core development company should also show you the automated tests and the deployment script, not only the running application.

Key features and components

What separates a useful build from a costly one.

Common integrations

Where the value usually comes from.

Security and long-term support

Choosing the release and patching cadence is part of the architecture.

• New builds target the current long-term-support .NET release per the .NET support policy.
• Authentication through Microsoft Entra ID with role-based authorization and audit logging.
• Security practices aligned with the OWASP Top 10 and dependency scanning in CI.
• Secrets in Azure Key Vault, never in code or configuration files.

ASP.NET web development company

An ASP.NET web development company builds web applications and APIs on Microsoft’s .NET platform. When comparing providers, ask which version of .NET they recommend, how they handle authentication and updates, and whether they can maintain existing systems as well as new ones. Ask for a deployment plan for Azure or your own servers, and for tests that run automatically whenever code changes. Scoping matters most with ASP.NET web development services, so ask for the list of pages, APIs and integrations in writing before any estimate is given.

Our .NET development process

We assess the systems and data involved, design the architecture on ASP.NET Core and Azure, build in two-week sprints with automated tests, integrate identity and business systems, deploy through CI/CD and support the application after launch.

How much does .NET software development cost?

As price figures, a focused ASP.NET Core application commonly costs $40,000-$100,000, an integrated business platform $100,000-$250,000, and a .NET Framework migration $30,000-$150,000 depending on size and test coverage.

Offshore or outsourced .NET development

A lower hourly rate is the pitch for offshore .NET development, and the saving holds only if the overlap in working hours and the quality of handover hold too. Decide what you are buying first. To outsource .NET development is to hand over delivery of a defined scope, whereas staff augmentation adds developers to a team you still manage.

Outsourcing .NET development suits a bounded build with a written specification and automated tests. It gets harder on an old .NET Framework system whose rules live in the heads of two employees, because documenting those rules becomes the first cost. In any .NET development outsourcing contract, settle who owns the repositories, the Azure subscription and the build pipeline before work starts.

Technology we typically use

Mainstream, maintainable choices.

Our .NET development tools depend on the machine. .NET development on Mac is supported, with Microsoft shipping Arm64 and x64 SDK installers for macOS, and Visual Studio Code for .NET development with the C# Dev Kit extension is the route its documentation lists.

Mistakes to avoid

Common causes of overruns and low adoption.

• Starting a new build on .NET Framework instead of modern .NET.
• Skipping the migration assessment and rewriting everything.
• Hard-coding connection strings and secrets.
• No automated tests before a framework upgrade.
• Ignoring Azure cost controls.
• Leaving identity to a custom login system instead of Entra ID.

Why choose Progression Agency for .NET development?

Engineering, design and go-to-market in one team.

• .NET engineering that fits the Microsoft systems you already run.
• Migration experience from .NET Framework to modern .NET.
• Azure architecture with cost controls built in.
• You own the code, data and accounts.
• Headquartered in New York City, working with clients nationwide and worldwide.

We work as a custom .NET development company, and the code and pipeline stay yours at handover. When a .NET development company, USA-based on paper, sends a proposal, ask where each developer sits. Our Microsoft .NET development services are scoped one system at a time, so .NET development solutions for a second system get their own estimate.

Related services

See custom software development, API development, backend development and desktop application development.

Frequently asked questions