Treevoxa offers .NET development services for businesses with systems written in C#: building new modules, extending ASP.NET Core applications, documenting and securing APIs, and modernising older .NET Framework applications without stopping the business that depends on them. Our dot net core development services cover new modules, upgrades and APIs on modern .NET.
.NET software development services we offer
- ASP.NET Core web apps and APIs for business systems and portals.
- Modernisation from the .NET Framework to modern .NET, in steps.
- API work: documenting, securing and versioning existing .NET APIs, and building new ones. See API development services.
- Integrations between .NET systems and payment providers, accounting software and newer services.
- Audits of .NET code bases: security, dependencies, tests and deployment.
ASP.NET development services: how we approach legacy systems
Most .NET work we are asked about is not greenfield. It is a system that has run a business for years and has become hard to change. We approach it the same way every time:
- Audit first. Framework versions, dependencies, tests, deployment and the parts nobody understands any more, written up with risks ranked.
- Stabilise. Add tests around the riskiest flows before changing them.
- Upgrade in steps, with the system working after every step.
- Replace, don't port, where it is cheaper: some old components are better rebuilt as small services.
- Document so the next developer does not inherit the same problem.
Our software design consulting covers the audit as a stand-alone engagement if you only need the assessment.
What we bring from our own products
If a new service sits beside your .NET system, we often build it in Node.js or Python behind a documented API, so each part uses the right tool.
The engineering rules that keep our own ERP and business systems reliable apply in any language: typed code, validated input, role-based access, audit trails for money, documented APIs and automated tests. Our products are built in TypeScript and Python; the discipline carries over to C#.
Tech stack for .NET projects
| Part | What we use |
|---|---|
| Framework | ASP.NET Core, modern .NET, C# |
| Data | SQL Server or PostgreSQL |
| API docs | OpenAPI (Swagger) |
| Front ends | React or Next.js, or the existing UI layer |
Engagement models for .NET work
- Fixed scope for a defined module, upgrade step or integration.
- Dedicated developer for ongoing .NET work. See hire dedicated developers.
- Hourly for audits, fixes and small changes.
What .NET development costs
The cost of .NET work depends most on the state of the existing code: test coverage, framework version, and how tangled the dependencies are. That is why we audit before we quote anything large. Our custom software development cost guide explains how quotes are built. We quote in US dollars, in writing.
Who .NET development is for
- Companies running C# systems that the original developers have left, and that now need changes.
- Teams on the .NET Framework facing the end of support for their stack or their servers.
- Businesses with Microsoft-centred infrastructure that want new modules to fit what they already run.
- Product owners who need an API in front of an old .NET system so new apps can use its data.
What a .NET audit covers
- Versions: the framework, runtime and every package, with what is out of support.
- Security: authentication, authorisation on every endpoint, input validation and secrets.
- Tests: what exists, what runs, and the riskiest flows with none.
- Build and deployment: how a change reaches production today, and how long it takes.
- A ranked plan: what to fix first, what to upgrade, and what to replace, with effort for each.
What to send us for a .NET quote
The framework version, a description of what the system does and who uses it, how it is hosted, and the change you need. Read access to the repository lets us scope accurately.
Do you work with SQL Server?
Yes. Many .NET systems run on SQL Server, and we work with the database you have. Moving to PostgreSQL is an option we only recommend when it saves real money or effort.
Questions to ask before you hire a .NET team
- Which .NET versions do your live projects run on?
- How would you upgrade our system without stopping the business?
- What tests would you add before changing anything?
- How do you document an API so other teams can use it?
- Who owns the code, and is it in our repository from day one?
Ask every bidder the same questions, in writing, and compare the answers before you compare the prices.
Working across time zones on .NET projects
We work remotely with a daily overlap window in your working hours, agreed before the project starts.