.NET Development Services
.NET Development Company For The Systems Your Business Runs On
Line-of-business software is judged over a decade, not a quarter. We design, build and hand over .NET systems that finance, operations and audit can all live with, then keep them current. Stallyons is a Delaware-registered US company whose senior engineers work hours you set.
Triple Protection Guarantee
- US-Registered Entity
- Signed IP Assignment
- Fixed, Written Scope
Triple Protection Guarantee:
- US-Registered Entity
- Signed IP Assignment
- Fixed, Written Scope
Engineers On Staff
0
+
Avg. Engineer Exp.
0
+
Years In Business
0
+
Why Build On .NET
Supported Long
LTS Backed
One Vendor Stack
Fits Estate
ASP.NET Core API
Web Or App
Data Integrity
Transactional
Strong Typing
Compiled
Data Security
Access Rules
Audit & Controls
Fully Traced
Communication Rhythm
Daily Sync
Cutover Plan
Rehearsed
IP Assignment
Signed
Delivery Overlap
Fixed
Hours
Code & IP Owner
You
Trusted By Startups
What A .NET Development Company Delivers
A .NET development company is usually brought in for software the business cannot stop using: the system finance closes the month on, the tool operations schedule from, the portal customers log into. The work is rarely a blank page. It is a set of rules nobody has written down for eleven years, an integration with something older still, and a cutover that has to happen without a bad Monday. The deliverable is a working transition, not a codebase.
Stallyons is registered in Delaware as a US company, and our engineers work inside an overlap window you set, with four-plus hours of daily contact. You sign a US contract, run diligence on a US entity and pay one US invoice. We have been building software for twelve-plus years across six continents, for CTOs, IT directors and operations leaders in North America, the UK and Europe, the Middle East, Singapore, Australia and New Zealand. Most arrive with a system too important to replace casually.
What .NET Development Covers
ASP.NET Core applications built for the people who use them daily: role-based access that matches your org chart, screens designed around the actual task, and audit trails that satisfy whoever asks for them later.
Business rules written down at last: the exceptions, approvals and edge cases that currently live in one manager's head, captured as testable code with the reasoning recorded beside it.
Data layers that hold up under load: an Entity Framework model that matches the schema, indexed queries, transactions that behave under contention, and migrations rehearsed before they run.
Integration with what you already run: ERP, CRM, payroll, warehouse and reporting systems, connected through interfaces that can be replaced without touching the rest.
Modernisation of older .NET Framework code, taken in stages, with the existing system running until the replacement has earned the switch rather than been promised it.
Deployment your own IT team can own: repeatable pipelines, documented environments, and a rollback path that has been tested rather than described in a document.
Why Enterprise Teams Choose Our .NET Development Services
- Ask who will write down the business rules. Most legacy systems have no specification, and a build that skips this step reproduces the bugs along with the behaviour.
- Find out how the cutover works. A weekend big-bang switch with no rehearsal and no rollback is the single most expensive decision in this kind of project.
- Ask what happens to the reports. Finance and operations run on outputs nobody mentions in the brief until the week they stop appearing.
- Pin down which version of .NET you will end up on, and when it stops being supported. Landing on a release already near end of life buys you a second migration.
- Ask how they will handle the integrations you cannot change. The old system that will not move is the constraint the whole plan has to be built around.
- Check what your own IT team is expected to run afterwards, and whether they have been given the pipelines, documentation and access to actually do it.
How To Start A .NET Development Project
Every project starts with a free 45-minute technical session. No slide deck, no sales script. You bring the current system, the constraints and who depends on it; you leave with a recommended approach, a scope and a timeline.
We are selective about new projects and cap how many run at once, because the review standard is the product. If the right answer is to fix what you have rather than replace it, we will say so.
Why Clients Choose Us
Full
Written IP Transfer
USA
Contract Entity
Yours
Repos & Pipelines
Named
Senior Level
Ready to have your .NET system designed and built?
What We Build With .NET
What We Build With Custom .NET Development
.NET is chosen where software has to be correct, auditable and still supported in ten years. These are the builds we take on most often. Every one of them has to fit an estate that was here first.
Business Applications
Operations, finance, HR, scheduling
End-to-End
Customer Portals
Accounts, self-service, billing
Role-Aware UI
Web API Layer
REST, gRPC, versioned contracts
Versioned
Legacy Modernisation
Framework to .NET 8, in stages
Live In Production
Workflow UI
Approvals, routing, exceptions
Rules Coded
Reporting & Analytics
SQL, warehouses, Power BI feeds
Auditable
APIs And Integrations
ERP, CRM, payroll, warehouse
Linked
Testing & Sign-Off
Unit, integration, UAT, regression
Sign-Off
Azure Cloud Migration
On-premise to Azure, in phases
Future-Proof
Support & Maintenance
Monitoring, fixes, releases, cover
Kept Running
Not sure what to replace first? Let's map the estate.
Common Challenges
Why Do .NET Builds Run Into Trouble?
Six patterns behind most business-system projects that arrive late, over budget, or hated by the people using them.
Rules By Rumour
01
Nobody wrote down what the old system actually does, so the build is reverse-engineered from screenshots and memory. The exceptions surface during testing, one week before the promised launch date.
The Spreadsheet Layer
02
Half the real process lives in spreadsheets the project never saw. The new system launches, and within a month those files are open beside it again.
Integration Left Last
03
The connection to the system that will not change gets scheduled for the final sprint. It is always the part that reveals the assumption everything else rested on.
Big-Bang Cutover
04
Everything switches over one weekend with no rehearsal and no way back. Monday brings the data problems nobody could see while the two systems were still separate.
Reporting Bolted On Late
05
The build covers the screens and forgets the numbers the business is actually managed by. Finance keeps the old system open purely to run the month-end reports from it.
Left On An Old Runtime
06
The project lands on a version already close to end of support, with nobody funded to move it. Three years later the same conversation starts again.
Recognise any of these? Let's plan the build.
Our .NET Dev Services
Six .NET Development Services We Deliver
Six ways to buy a .NET build from one accountable partner. Run one, or run several in sequence under a single contract.
Custom .NET Development Work
01
A defined business system designed, built, tested and released: rules documented, architecture agreed, milestones you sign off, and a written plan approved before any code exists.
ASP.NET Core Builds
02
Web applications and portals on current ASP.NET Core: role-based access, screens built around the real task, tested business rules, and an audit trail you can hand to a reviewer.
Legacy .NET Modernisation
03
.NET Framework applications moved to .NET 8 in stages, with the old system running and a rehearsed cutover rather than a weekend of hoping.
Data & SQL Server Work
04
Schema design, Entity Framework models that match it, query and index tuning, migrations rehearsed against a copy of production, and reporting that reconciles.
Integration & Azure Work
05
Connecting ERP, CRM and warehouse systems, and moving workloads to Azure in phases, so each step is reversible and nothing depends on all of it landing.
.NET Support & Maintenance
06
Runtime upgrades before support lapses, security patching, performance work and a small change allowance each month, so the system never quietly becomes a risk item.
Not sure which .NET service fits? Let's scope it together.
Why Choose Us
What Makes Our .NET Development Company Different
The decisions that determine whether a business system is still trusted in its eighth year.
A US Legal Entity
01
Stallyons is registered in Delaware. Your contract, your invoice and your legal recourse sit with a US company, not an unknown one.
Rules Written First
02
We document what the business actually does before rebuilding it, so you end up with a specification as well as a system, and both agree.
Overlap You Set
03
You choose the hours we share with your working day, and stand-ups, reviews and escalations all happen inside that window.
Cutover Rehearsed
04
Migrations and go-live are practised against a copy of production, with a rollback path that has been tested, so the switch is boring by design.
Reviewed Code
05
Every merge is reviewed against an agreed definition of done, on your board, where you can read it yourself.
One Contract
06
One contract covers the engagement, so procurement, legal and finance each deal with a single named counterparty.
Ready to see how we would approach your .NET build?
Our Process
From First Call To .NET Development Launch
A delivery process built to surface the expensive decisions early, before anyone writes code.
Discovery
Map the current system, users, data and reports
Scoping
Agree architecture, milestones and estimate
Design
Business rules, schema and interfaces agreed
Contracting
NDA, IP assignment, access and onboarding
Deliver
Built in milestones, reviewed on merge
Cutover & Care
Rehearse, switch over, then support it
Want to see how this maps to your roadmap?
Technology Stack
The Full Stack Behind Our .NET Development
Proven Microsoft-estate tooling across every layer: application, data, integration and what runs them.
Core & Web UI
.NET 8 / C# 12
ASP.NET Core
Blazor / Razor
Minimal API
TypeScript
Data & Persistence Layer
SQL Server
Entity Framework
PostgreSQL DB
Dapper
Redis / Blob Store
Integrations
REST & gRPC APIs
Service Buses
RabbitMQ And Kafka
SOAP & Legacy
ERP & CRM Connectors
Testing & Quality
xUnit / NUnit
Moq / Fakes
SonarQube QA
Playwright E2E Tests
Load & Soak Tests
Cloud & DevOps
AWS / Azure / GCP
Docker / K8s
Terraform / Bicep
GitHub Actions / CI
Datadog / Grafana
Industries We Serve
.NET Development Services For Regulated Industries
Teams who already know your approval chains and audit requirements spend month one building, not asking.
Fintech & Payments
Ledgers, settlement, compliance
Healthcare & HealthTech
Scheduling, claims, patient records
Retail & E-Commerce
Stock, orders, back-office tools
EdTech & Learning
Enrolment, records, finance links
SaaS & Digital Products
Tenancy, entitlements, invoicing
Logistics & Supply Chain
Warehouse, fleet, ERP links
Manufacturing & IoT
Production, quality, maintenance
Agencies & Consultancies
White-label .NET delivery
We know your constraints. Let's plan the .NET build.
How We Compare
.NET Development vs In-House vs Freelance
An honest look at your three ways to build it.
| Capability | In-House IT Team | Freelance Marketplace | Large Systems Integrator | Stallyons Technologies |
|---|---|---|---|---|
| Business Rules Documented | In People's Heads | ✕ Not Attempted | Discovery Phase Billed | Written & Testable |
| Cutover Rehearsed | If Time Allows | ✕ Out Of Scope | Change Request | Practised & Reversible |
| Legacy Integration Owned | Shared Ownership | ✕ Declined | Subcontracted | Scoped From Day One |
| Reporting Included | Built Later | ✕ Not Offered | Separate Workstream | In The Same Scope |
| Runtime Support Horizon | Rarely Planned | ✕ Whatever Is Known | Contract Dependent | Current LTS Target |
| Estimate With Milestones | Internal Roadmap | ✕ Hourly Only | Fixed Bid, Vague Scope | Itemised & Phased |
| Contracting Entity | Your Payroll | ✕ Platform Terms | Local Entity | US-Registered LLC |
| Handover To Your IT | Already Internal | ✕ Nothing Written | ✕ Vendor Lock-In | Pipelines & Docs |
See the difference for yourself
Complete Engagement
Everything Included In A .NET Development Project
From Scoping to Contracting to Delivery, One Vendor
Here's everything included when we build your .NET system:
All-Inclusive .NET Delivery: No Hidden Fees, No Surprises.
Every .NET project includes all eight components above. One contract, one senior team, one agreed scope, and no vendor sprawl.
🔒 No obligation. We'll deliver a detailed proposal within 48 hours.
Plus, Get These Free Bonuses
Free .NET Estate Review
A written read on what you run today: which parts are worth modernising, which should be left alone, and where the support horizon puts a deadline on the decision.
Included Free
Delivery Plan & Estimate
A phased delivery plan with scope, milestones, a stack recommendation and a transparent, itemized estimate for the engagement.
Included Free
Free Cutover Checklist
The questions we would ask any .NET development company about rules, data, integrations and go-live, so you can put us through the same test.
Included Free
Risk-Free Partnership
Our .NET Development Promise
We stand behind every engagement with commitments that protect your investment.
01
Scope Agreed First
Scope, model, working hours and cost structure are written down and agreed before contracting, so nothing is discovered later.
02
Built to Last
Senior developers, code review, automated tests, security and accessibility audits, and clean, documented code you fully own.
03
IP And Access Protected
NDA and IP assignment are signed before access, permissions are scoped per person, and your accounts stay under your control.
Start your .NET build with confidence, backed by our Triple Protection Guarantee.
Track Record
Engagements That Ship, Scale, and Compound
500+
Projects Delivered
29+
Service Categories
81%
Repeat Client Rate
4.9 ★
Clutch Rating
"We came to Stallyons after burning two years and four vendors on a multi-platform launch that kept slipping. They scoped it end-to-end — web app, iOS, Android, an AI summarization layer, and a Shopify integration — and shipped it in 22 weeks. One team, one budget, one quality bar. We've handed them three more engagements since."
Mark Sawyer
CEO/Founder
PlatinumLED
"Stallyons rebuilt our customer-facing portal, integrated three legacy systems, shipped an AI document analysis pipeline, and brought our compliance posture to SOC 2 — all under one engagement. The senior engineers on the team have shipped at companies five times our size. It's the best vendor decision we've made in a decade."
Mark Sawyer
CEO/Founder
PlatinumLED
FAQ
Frequently Asked Questions About .NET Development
It builds and delivers the business systems a company runs on, usually replacing or extending something already in use. The work starts by writing down rules nobody has documented, agreeing an architecture and a schema, then building in milestones, testing with the people who will use it, rehearsing the switch-over and supporting what goes live. The deliverable is a working transition, not a repository.
It matters a great deal. .NET Framework is the older Windows-only line, still running a large share of business software but no longer where new capability lands. .NET 8 is the current cross-platform line, actively supported, faster and far cheaper to host and deploy. If you are on Framework, the question is not whether to move but when, and in what order. We plan that as stages rather than a single rewrite.
Cost tracks the number of integrations, how much undocumented behaviour must be recovered, and how much data has to migrate cleanly. The code itself is rarely the expensive part. Any figure quoted before scoping is a guess, so we scope first and then itemise the estimate against milestones you can approve or defer one at a time.
In stages, with both systems running for a period. We take a slice that can stand alone, build it, run it alongside the old one and reconcile the outputs before anything is switched off. The cutover is rehearsed against a copy of production and has a tested rollback, so go-live is a planned event rather than a gamble on a weekend.
You do, from the first commit. NDA and IP assignment are signed before anyone gets repository or database access, with no licence-back and no shared ownership. Repositories, schema definitions, deployment pipelines and documentation live in your own accounts throughout, so there is nothing to hand back later.
Yes, and with whatever sits beside them. Most estates we join are a mix: SQL Server holding the important data, some on-premise servers, an Azure subscription somebody started, and a few systems nobody wants to touch. We work inside your environments under your access rules rather than requiring a move before we can start.
Most of our .NET work starts that way. The first pass reads the solution structure, the data model, the integration points and whatever tests exist, and ends in a written list of what is safe to leave alone and what is costing you every release. We then change it in slices behind your review process.
Go-live is a milestone, not the end. Pipelines, environment documentation and runbooks are handed to your own IT team so they can operate it without us. From there you can put the system on a support cadence with us for runtime upgrades, patching and small changes, or keep it entirely in-house with what you have been given.
Still have questions? Let's talk.
Schedule an appointment with us today!
Ready to Build Your .NET System Properly?
Get a free consultation. We'll discuss the current system, recommend an approach, and send a detailed written proposal.
