Custom .NET development

Custom .NET development company

Enterprise systems in C#, built to still be maintainable when the people who wrote them have moved on.

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  • 40+AI systems shipped to production
  • 3.5×Median speed-up vs. in-house build
  • 99.9%Uptime across deployed models
What we build

Custom .NET development services

.NET is chosen for systems that have to last. Long-lived business applications, regulated environments, and integrations with infrastructure that predates the project. Our custom .NET development services are shaped around that: correctness, maintainability, and an upgrade path that stays open.

.NET Framework to modern .NET migration

Framework 4.8 applications running on Windows-only infrastructure, cut off from every performance and tooling improvement since 2019. We assess what actually blocks the move, sequence it so the system stays shippable throughout, and stop the migration becoming a rewrite.

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Cloud migration and Azure

Lift-and-shift where that is genuinely the right answer, and re-platforming where it is not. App Service, Functions, Service Bus, and managed SQL. We tell you which of your workloads should not move.

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Tech & tools

Our .NET development stack

We pick for the constraint, not the habit. The first question on any .NET engagement is which .NET you are actually on, because the answer changes everything downstream.

Modern .NET (LTS — .NET 10)

For anything new and anything being migrated. Cross-platform, materially faster, and still receiving investment. This is the default we recommend unless a hard dependency blocks the move.

.NET Framework 4.8

Only where a hard dependency genuinely blocks the move. It is in maintenance and it is Windows-only. Staying is a decision with a cost, and we will put a number on it rather than leave it implicit.

ASP.NET Core & Blazor

ASP.NET Core for web applications and APIs — Minimal APIs where the surface is small, MVC or Razor Pages where it is not. Blazor when a rich interface belongs in C# next to the domain model.

Entity Framework Core for most data access, with Dapper where a query needs hand control. Server-side Blazor for internal applications, WebAssembly where the client needs to work without a live connection.

Framework

  • .NET 10 LTS logo.NET 10 LTS
  • C# logoC#
  • ASPASP.NET Core
  • BLBlazor
  • MAMAUI

Data

  • SQL Server logoSQL Server
  • PostgreSQL logoPostgreSQL
  • EFEF Core
  • DPDapper
  • Redis logoRedis

Messaging

  • SBAzure Service Bus
  • RabbitMQ logoRabbitMQ
  • MTMassTransit
  • SRSignalR

Identity

  • ENEntra ID
  • ISIdentityServer
  • OAOAuth
  • OIOpenID Connect

Infra

  • Azure logoAzure
  • Docker logoDocker
  • K8Kubernetes
  • AOAzure DevOps
  • GitHub Actions logoGitHub Actions

Quality

  • XUxUnit
  • TCTestcontainers
  • RARoslyn analyzers
  • OTOpenTelemetry
How we design

Custom .NET application architecture

.NET applications rarely fail from lack of structure. They fail from too much of it, applied before anyone knew what the system needed. Four decisions we make deliberately.

Which .NET you are on

This is a fork, not a version bump. Framework 4.8 means Windows-only hosting, no access to current performance work, and a shrinking pool of engineers willing to work on it. Modern .NET means the opposite. Every other architectural decision depends on this one, so we settle it in week one with a real assessment rather than an assumption.

How much abstraction the system has earned

Clean Architecture, CQRS, and a mediator layer are good tools and a bad default. We have inherited three-project solutions with five layers of indirection wrapping a single database table. We add structure when a boundary is real, and we can explain why each layer exists. If we cannot, it comes out.

Where the query boundary sits

EF Core's deferred execution means an IQueryable returned from a repository is a query nobody has finished writing yet, and it gets completed somewhere with no idea what it costs. We terminate queries at the boundary, use no-tracking reads where nothing is being mutated, and set query budgets per endpoint.

Async the whole way down

One synchronous call inside an async path blocks a thread pool thread, and under load that becomes starvation: everything slow, nothing obviously broken. No sync-over-async anywhere, cancellation tokens threaded through, and load testing held long enough to expose it.

How we ship

Our .NET development portfolio

The pattern we use on .NET platforms: settle the runtime fork early, keep domain logic separable from the framework, and leave the upgrade path open.

Framework migrations

Sequence the move. Do not rewrite by accident.

Enterprise buyers searching these keywords are usually afraid of a Framework migration going wrong. The obvious approach — freeze features, rebuild everything, cut over in one weekend — is how migrations become rewrites.

We assess what actually blocks the move, sequence packages and Windows-only dependencies so the system stays shippable throughout, and put a number on staying versus migrating before anyone commits.

Domain logic stays out of the framework shell, so next year's LTS upgrade is a planned effort rather than a quarter-long freeze.

Abstraction discipline

Structure when a boundary is real.

Clean Architecture and CQRS are good tools and a bad default. We add layers when we can explain why each one exists. If we cannot, it comes out.

See our work

Migration

Framework to modern .NET, still shippable

Version and dependency audits first. Abandoned packages usually drive more cost than the framework itself. You keep the assessment either way.

Learn more

Enterprise APIs

Integrations with typed contracts

ERPs, identity providers, and internal platforms with undocumented behaviour. Real payload shapes in tests, not optimistic mocks.

Learn more

Azure

Cloud moves with an honest scope

Lift-and-shift where it fits, re-platforming where it does not. We tell you which workloads should stay put.

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Industries

Custom .NET development across industries

Domain logic differs by sector. The requirement to be correct does not.

Custom .NET development for financial services and insurance platforms

Financial services and insurance

C# has a native decimal type built for money, which removes an entire class of rounding error that other runtimes work around with libraries. Combined with strong typing and a mature audit and identity story, this is why .NET holds the ground it does in finance. We build ledgers, reconciliation, and reporting where being approximately right is not acceptable.

Explore Fintech
Custom .NET development for healthcare administration and clinical workflow

Healthcare

Patient administration, clinical workflow, and integration with record systems that have been in place for a decade. Role boundaries and audit trails are enforced at the domain layer rather than the interface, so a new integration cannot route around them.

Explore Healthcare
Custom .NET development for manufacturing and supply chain systems

Manufacturing and supply chain

ERP and WMS integration, production scheduling, and shop-floor systems. This is where .NET's ability to talk to old infrastructure matters more than any framework feature, and where migration projects usually live.

Explore Logistics
Custom .NET development for government and public sector platforms

Government and public sector

Long procurement cycles, long service lives, and accessibility and audit requirements that are contractual rather than aspirational. .NET's LTS cadence and Microsoft's support commitments matter here in a way they do not elsewhere.

Explore industries
Custom .NET development for enterprise B2B and multi-tenant platforms

Enterprise B2B platforms

Multi-tenant systems with complex permission models and identity federation into customers' own directories. Entra ID and OpenID Connect are first-party rather than bolted on.

Explore SaaS
Discovery

Plan your .NET development project

Bring us the system you're building, or the Framework application you have been putting off. Discovery takes one to two weeks and produces an architecture proposal and a fixed estimate.

You keep the document either way.

Custom .NET development company — technical discovery call
Scoping

Custom .NET development cost factors

We scope from the constraint, not from a price list. Five things move the number on a .NET build.

Custom .NET development cost factors — production infrastructure

Which .NET you are starting from

Greenfield on modern .NET, a Framework application that migrates cleanly, and one with a hard Windows dependency are three different projects. The assessment comes before the estimate.

Integration count and integration quality

Eleven well-documented APIs cost less than three undocumented internal systems. Cost sits in discovery, not in the code.

Identity and compliance requirements

Federation into customer directories, audit evidence, and access controls that survive a security review are real engineering rather than configuration.

Existing test coverage

On legacy .NET work this drives more of the cost than the code itself. Changing a system with no tests means writing tests first or accepting risk we would not accept.

Who operates it after launch

A system your team runs needs different documentation and tooling than one we maintain.

Discovery produces a fixed estimate. You see the number before you commit to the build.

When .NET is the wrong choice

We would rather tell you now than three months in.

  • An MVP with an unproven idea

    .NET rewards systems that live for years and taxes ones that might not survive the quarter. If you need a market answer in eight weeks, Laravel website development or Python web development will get you there sooner.

  • Machine learning and data work

    ML.NET exists. The ecosystem is not close to Python's and pretending otherwise costs you more than the language consistency saves. We build the .NET application and put Python underneath it. Python web development services.

  • Sustained real-time at very high connection counts

    SignalR is good and covers most cases well. Past a certain scale, Node.js web development is the more natural fit.

  • A team with no C# and no plan to hire it

    The best stack is often the one your people can maintain on a Tuesday afternoon without us.

We build in eight stacks. The recommendation follows the problem. See engineering services.

How we engage

.NET development engagement models

All three carry the same handover terms. Source, infrastructure, and documentation are yours throughout, and you have repository access from the first sprint.

Fixed scope

Defined requirements, agreed deliverables, a fixed price. Best when the problem is well understood and the boundary is clear. You know the total before work starts, and change requests are priced separately rather than absorbed silently.

Variable scope

Sprint-based delivery with priorities set at each sprint boundary. Best when discovery is ongoing or requirements will move. This is usually the right shape for migration work, where the third month teaches you things the first month could not.

Staff augmentation

Our .NET engineers working inside your team, under your process and your management. Best when you have the direction and need capacity. Engineers stay with your project rather than rotating.

How we work

Our .NET development process

A defined path from technical scope to handover, with repository access from the first sprint.

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How to choose

Choosing a .NET development company

Ask any custom .NET development company three questions. How do they decide how much abstraction a system needs. Where do they terminate EF Core queries. What is their sequence for a Framework migration that has to stay shippable throughout. The answers separate engineers who have maintained .NET systems from ones who have only started them.

The honest case for an in-house hire: if this platform is your core product and needs continuous work for years, hire. We will say so on the call. Our work is strongest when you need senior .NET capacity now, when a migration has a defined end, or when your team needs the first version built properly and then handed over.

CriterionXororaIn-house hireFreelancer
Time to start1–2 weeks10–16 weeks to hire1–3 weeks
Senior C# availabilityImmediateCompetitive and costlyVariable
Migration experienceIncludedDepends on the hireRarely
Continuity if someone leavesTeam-backedSingle point of failureSingle point of failure
Upgrade path maintainedYesDependsRarely
Source and infra ownershipYoursYoursNegotiate
Time to start
  • Xorora

    1–2 weeks

  • In-house hire

    10–16 weeks to hire

  • Freelancer

    1–3 weeks

Senior C# availability
  • Xorora

    Immediate

  • In-house hire

    Competitive and costly

  • Freelancer

    Variable

Migration experience
  • Xorora

    Included

  • In-house hire

    Depends on the hire

  • Freelancer

    Rarely

Continuity if someone leaves
  • Xorora

    Team-backed

  • In-house hire

    Single point of failure

  • Freelancer

    Single point of failure

Upgrade path maintained
  • Xorora

    Yes

  • In-house hire

    Depends

  • Freelancer

    Rarely

Source and infra ownership
  • Xorora

    Yours

  • In-house hire

    Yours

  • Freelancer

    Negotiate

Good to know

Custom .NET development FAQs

Ask how they decide how much architecture a system needs, because over-engineering is the characteristic failure of this stack. Ask where they terminate EF Core queries. Ask how they would sequence a Framework migration so the system stays shippable throughout. Also ask who owns the source and infrastructure after launch.

Power your next digital move.

Tell us what you're building, or what you're stuck maintaining. We will tell you what it takes, what it costs, and whether .NET is the right call.

Most conversations start with a 30-minute technical call. No deck.

See our work
info@xorora.com
+1 512-764-7666
+92-332-0555328