How to Choose a .NET Development Company in 2026

To choose a .NET development company, check that it builds on a supported .NET release (in late 2026 that means .NET 10 for most new work), has experience with your type of application and hosting, can migrate older .NET Framework code if you have it, writes automated tests and follows secure coding practices, and hands over code, cloud accounts and documentation that you control. This guide shows you what to check, which questions to ask, the red flags to watch for and how to compare proposals.

Why version planning matters right now

Microsoft releases a new major version of .NET every November. Under the official .NET support policy, even-numbered releases are Long Term Support (LTS) with three years of free support and patches, and odd-numbered releases are Standard Term Support (STS) with two years.

Both .NET 8 and .NET 9 reach end of support on November 10, 2026. If your applications run on either, upgrading to .NET 10 should be on your roadmap now, and it is a good test of any company you are considering. Ask how it would plan, test and deploy that upgrade.

Know what kind of .NET work you need

.NET covers a wide range of software. Match the company to your project type:

• Web applications and APIs with ASP.NET Core, often with a JavaScript front end or Blazor.
• Enterprise line-of-business systems such as ERP extensions, portals and workflow tools.
• Legacy modernisation: moving .NET Framework, Web Forms, WCF or old MVC applications to modern .NET.
• Cloud-native services on Azure or another cloud, using containers, functions and managed databases.
• Desktop and cross-platform apps with WPF, WinForms or .NET MAUI.
• Integrations with Microsoft 365, Dynamics, SharePoint or third-party systems.

A company that excels at greenfield ASP.NET Core APIs may have little experience untangling a fifteen-year-old Web Forms application, and that kind of migration needs patience and careful testing. Ask for examples that match your situation.

.NET remains a mainstream choice for this kind of work. In the Stack Overflow Developer Survey 2025, 21.3% of professional developers who answered the web frameworks question reported using ASP.NET Core, which means skills are widely available if you ever need to change suppliers or hire in-house.

The .NET company checklist

• Current versions: new projects on .NET 10, with a plan for future LTS upgrades.
• Architecture: clear reasons for their choices, whether a modular monolith, microservices or serverless functions.
• Data access: experience with Entity Framework Core and with tuning SQL Server or PostgreSQL queries.
• Testing: unit and integration tests run automatically in a CI pipeline, such as Azure DevOps or GitHub Actions.
• Security: authentication with standard identity providers, role-based authorisation, secrets kept out of code and dependency scanning. The OWASP Top 10:2025 is a useful checklist to discuss.
• Cloud skills: if you use Azure, experience designing against the Azure Well-Architected Framework pillars of reliability, security, cost optimisation, operational excellence and performance efficiency.
• Observability: logging, metrics and alerts set up so problems are caught before users report them.
• Documentation: architecture notes, setup guides and runbooks as part of every delivery.

Questions to ask a .NET development company

1. Which .NET version will you use, and how will you handle the next LTS upgrade?
2. Can you show .NET projects similar to ours in size, industry and architecture?
3. Have you migrated .NET Framework applications to modern .NET? What was hardest?
4. How do you structure solutions so that business logic is testable?
5. Which identity and authentication approach do you recommend for us?
6. How do you manage secrets, configuration and environment differences?
7. What does your CI/CD pipeline look like, and who owns it after handover?
8. How do you estimate cloud running costs, and how do you keep them under control?
9. Who will work on our project, and what are their .NET and cloud certifications or experience?
10. What does support look like after launch, including security patches?

Red flags

• New work on an unsupported version. Starting a project on .NET 6 or older .NET Framework without a compelling reason.
• "Rewrite everything" as the first answer to a legacy system, without an incremental option or a risk assessment.
• Cloud resources in the vendor's subscription only. You should own your Azure or other cloud subscription.
• Connection strings and keys in source control. Ask how secrets are stored.
• No automated tests for business-critical logic, especially in finance, healthcare or logistics systems.
• Vague licensing answers. Third-party components and SQL Server or Windows licences should be identified and costed.

Legacy migration: how to judge a company's plan

Many .NET buyers are not starting from scratch. If you have an older .NET Framework application, ask each company to describe its migration approach in writing. A credible plan usually includes:

• An inventory of projects, dependencies, third-party libraries and Windows-specific features.
• A decision on whether to migrate in place, move piece by piece behind a shared front door, or rebuild specific modules.
• Automated tests written around critical behaviour before changes begin, so regressions are caught.
• A deployment plan that lets old and new parts run side by side during the transition.
• A clear list of what will not be migrated, such as reports or features nobody uses.

Be wary of fixed-price quotes for large migrations before any code has been reviewed. A short, paid assessment that produces a migration plan is a sensible first step and gives you a document you can take to other companies.

Check references and run a small pilot

Portfolios and proposals only tell you so much. Before signing a large contract, take two extra steps.

First, speak to at least two past clients, ideally ones whose projects resemble yours. Prepare specific questions rather than asking whether they were happy:

• Did the team deliver what was agreed, and how close were the final costs to the estimate?
• How did the company handle a problem, such as a production incident, a missed deadline or a change in requirements?
• Did the people named in the proposal actually do the work?
• How easy was it to understand the code and documentation after handover, or to bring in another team?
• Would you hire them again for your next .NET project?

Second, consider a paid pilot of two to four weeks. Good pilot tasks are real but contained: an API endpoint with tests, a small module of a migration, or a performance investigation on one slow page. Ask for the work to be delivered through a pull request into your repository, with a short write-up of decisions and risks. Review it with an independent senior .NET developer if you do not have one on staff.

A pilot costs a little up front, but it shows you how the team communicates, estimates, writes code and responds to feedback. It is far cheaper than discovering a mismatch six months into a large build. If the pilot goes well, you also start the main project with momentum, working tooling and a shared understanding of your codebase.

Comparing .NET proposals

.NET companies on Trusted IT Firms

Trusted IT Firms lists 122 companies under .NET development, plus 71 under .NET Core and 68 under ASP.NET. Among the .NET companies, 47 list an hourly rate of $25 to $75, 36 list $1 to $25 and 13 list $75 to $250. By location, 52 are .NET companies in the United States and 47 are .NET companies in India. If your project runs on Microsoft's cloud, you can also browse companies listing the Azure platform.

Next steps

Write a brief that states your current .NET versions, hosting, integrations and goals. Shortlist three to five companies, ask the questions above and request a short paid assessment for any migration work. Start with the companies listed on Trusted IT Firms, and if you run a .NET firm, list your company for free.

Frequently asked questions

Which .NET version should a new project use?

For most new projects in late 2026, .NET 10. It is a Long Term Support release, released on November 11, 2025, with support until November 14, 2028.

When do .NET 8 and .NET 9 reach end of support?

Both reach end of support on November 10, 2026, according to Microsoft's .NET support policy. Plan upgrades to .NET 10 before then.

What is the difference between LTS and STS releases?

LTS releases (even numbers) get three years of free support and patches, and STS releases (odd numbers) get two years.

Should I rewrite my old .NET Framework application?

Not necessarily. Many applications can be migrated step by step. Ask for a paid assessment that compares incremental migration with a rebuild before committing.

Do I need a .NET company with Azure experience?

Only if you host on Azure or use Microsoft cloud services. If you do, ask how they design for reliability, security and cost, and make sure the subscription is in your name.

Sources

• .NET and .NET Core official support policy (Microsoft)
• Stack Overflow Developer Survey 2025: Technology
• Azure Well-Architected Framework (Microsoft Learn)
• OWASP Top 10:2025