Technologies / .NET
.NET app development for mobile backends and Microsoft-stack teams
.NET app development makes the most sense when your company already runs on Microsoft: C# developers, SQL Server, Azure and staff who sign in with Microsoft accounts. In that setting, an ASP.NET Core API behind your mobile app fits your existing skills, security model and hosting, instead of adding a new language to support. This page is for CTOs and IT leads deciding where .NET belongs in a mobile project.
.NET (formerly .NET Core) is one of the backend options in our mobile app development technologies overview. For C# on the phone itself, see our .NET MAUI app development service.
- New work on .NET 10 LTS
- Upgrade plans for .NET 8 and 9
- Hosted in your own Azure or cloud account
- Code in your own repository
What .NET means today, and why the name changed
.NET Core was Microsoft’s open-source, cross-platform rewrite of the original Windows-only .NET Framework. From .NET 5 onward, Microsoft dropped “Core” from the name, so “.NET 10” today is the direct successor of .NET Core. It runs on Linux, Windows and macOS, in containers and on every major cloud, not only Azure.
For a mobile app, the relevant parts are ASP.NET Core for web APIs, Entity Framework Core for database access, SignalR for real-time messaging and background worker services for queued jobs. If your team still runs older .NET Framework applications, those stay on Windows; new mobile-facing services should be on modern .NET.
.NET LTS releases and the November 2026 deadline
Microsoft’s .NET support policy sets the upgrade budget for any .NET backend. Long-term support (LTS) releases get three years of support; standard-term support (STS) releases get two.
- .NET 10 (LTS) was released on 11 November 2025 and is supported until 14 November 2028.
- .NET 9 (STS) and .NET 8 (LTS) both reach end of support on 10 November 2026.
That second line matters now. Any API running on .NET 8 or .NET 9 stops receiving security fixes in November 2026. For backends that handle logins, payments or personal data, running an unsupported runtime is a risk most security reviews will flag. We start all new .NET app development on .NET 10 and plan upgrades for older services in order of exposure: public APIs first, internal tools after.
What an upgrade usually involves
Moving from .NET 8 to .NET 10 is normally a planned upgrade rather than a rewrite: update the target framework and packages, fix breaking changes flagged by the compiler and analysers, rerun tests, then release behind a staged rollout. Older services with no tests or with abandoned packages take longer, which is why we audit first and give a typical effort estimate in hours, labelled as an estimate.
When .NET app development is the right call, and when it is not
We recommend .NET when the backend needs to live inside an existing Microsoft environment. Common cases are enterprises whose staff sign in with Microsoft Entra ID, companies with a C# team that will own the API after launch, apps that read from SQL Server or Dynamics, and regulated organisations that have already approved Azure. Our enterprise mobile app development work often lands here.
We usually do not recommend .NET for a startup with no existing stack. A Node.js or Laravel API, or a managed backend such as Firebase, reaches an MVP with fewer moving parts and a larger pool of freelance help. .NET is a strong platform, but its main advantage is fit with what you already run.
.NET fits when
- Your team already writes C#
- Staff sign in with Microsoft accounts
- Data lives in SQL Server or Dynamics
- Azure is already approved by security
- You are moving a Xamarin app to MAUI
What we build with .NET
The four .NET jobs that come up most in mobile projects.
ASP.NET Core APIs for mobile apps
Versioned REST endpoints, token-based auth, push triggers and file uploads, designed around app screens. Our REST and GraphQL API development page covers the design rules we follow.
Internal employee apps on Microsoft identity
Mobile apps for field staff, approvals and inspections, with single sign-on through the company’s Microsoft accounts. See internal employee app development.
.NET MAUI apps
C# apps for iOS and Android from one codebase, sharing models with the backend. Microsoft says MAUI 10 is supported until 11 May 2027, and MAUI 9 went out of support on 12 May 2026.
Xamarin to .NET migration
Xamarin support ended on 1 May 2024. Projects must become SDK-style but do not need a rewrite. Our Xamarin migration services cover the plan.
Still running an API on .NET 8 or .NET 9?
Both reach end of support on 10 November 2026. Share your repository or a service list and within one business day we reply with an upgrade order and the main risks we see.
.NET compared with other mobile backends
How .NET app development compares with the backend options we build most often.
| .NET (ASP.NET Core) | Node.js | Laravel | Django | |
|---|---|---|---|---|
| Language | C# | JavaScript / TypeScript | PHP | Python |
| Support cycle | LTS 3 years, STS 2 years | LTS about 30 months | 2 years security fixes | LTS 3 years |
| Microsoft integration | Strongest | Good via SDKs | Good via SDKs | Good via SDKs |
| Shares code with the app | With .NET MAUI | With React Native | No | No |
| Best for | Microsoft-stack enterprises, C# teams | Real-time features, TypeScript teams | Workflow-heavy business apps | Data and AI-heavy apps |
How .NET fits the stack, the team and the cloud
A .NET backend works with any mobile front end. Most of our .NET APIs serve native Swift and Kotlin apps or Flutter and React Native apps, not only MAUI. We generate typed API clients from an OpenAPI description so each app stays in step with the server.
Hosting is flexible. Azure App Service or Azure Container Apps are the natural fit in a Microsoft environment, but the same container runs on AWS or Google Cloud. For push notifications, Azure Notification Hubs sends to Apple and Google services from one backend. Our cloud backend setup and hosting service covers environments, monitoring and cost controls in your own account.
On the people side, C# developers are common in enterprise IT, so your internal team can usually take the backend over. If you need extra capacity, you can hire backend developers for .NET with a two-week trial.
Code-quality practices on our .NET projects
What you can check in your repository and cloud account.
- Target framework on a supported release, with the next upgrade date in the backlog
- Nullable reference types enabled and analyser warnings treated as errors in CI
- Entity Framework Core migrations reviewed in pull requests and tested on a copy of production data
- Secrets in Azure Key Vault or the cloud’s secret manager, never in appsettings files
- Unit and integration tests for API endpoints, authorisation and business rules
- OpenAPI description generated from code and used to build typed mobile clients
- Health checks, structured logging and Application Insights or similar monitoring
.NET app development: frequently asked questions
Is .NET Core the same as .NET today?
Yes, in practice. .NET Core was the cross-platform, open-source version of .NET, and from .NET 5 Microsoft dropped “Core” from the name. Current releases such as .NET 10 are its direct successors. They run on Linux, Windows and macOS. The older .NET Framework is a separate, Windows-only product that we do not use for new mobile backends.
Which .NET version should a new project use?
.NET 10, the current long-term support release. Microsoft released it on 11 November 2025 and supports it until 14 November 2028. LTS releases get three years of support and STS releases two, so starting on an LTS gives you the longest runway before a required upgrade. We note the next upgrade date in the backlog from day one.
What happens when .NET 8 support ends?
Microsoft ends support for both .NET 8 and .NET 9 on 10 November 2026. Apps keep running, but they stop receiving security fixes, which matters for any API that handles logins, payments or personal data. We recommend upgrading public-facing services to .NET 10 first. It is usually a planned upgrade, not a rewrite.
Can a .NET backend serve iOS and Android apps built in Swift, Kotlin or Flutter?
Yes. An ASP.NET Core API speaks standard HTTP and JSON, so any mobile app can use it. Most of our .NET backends serve native or Flutter and React Native apps. We publish an OpenAPI description from the code and generate typed clients for each app, so changes on the server are caught at build time on the client.
Should we build the mobile app in .NET MAUI too?
Only if C# on the client is a real advantage, such as an existing Xamarin app or a C# team that will maintain it. MAUI follows .NET’s release rhythm, with each major version supported for at least six months after its successor ships, so plan regular upgrades. For many consumer apps, Flutter, React Native or native builds are a stronger fit.
Does .NET lock us into Azure?
No. Modern .NET runs in standard containers on Linux, so the same API can be hosted on AWS, Google Cloud or your own servers. Azure is often the easiest fit for companies already using Microsoft identity and SQL Server, but it is a choice, not a requirement. Cloud accounts stay in your name either way.
Put your mobile backend on a supported .NET release
Book a 30-minute scoping call. We will look at your Microsoft environment and app plans and tell you where .NET fits, what needs upgrading and how it connects to your mobile apps.