Windows apps

Modern Windows apps for real work.

Modern Windows apps on .NET and WinUI — fast, secure and ready for enterprise fleets and the Microsoft Store. Free working prototype in 1 day, then a production release at a fixed price and date.

C#.NETWinUI 3

Get your free prototype 30-min call · no commitment

Ledgerly—▢✕

Home

Invoices

Customers

Reports

Settings

Invoices＋ New invoice

Outstanding

€24,310

Paid this month

€86,900

Overdue

€3,180

NumberCustomerAmountStatus

INV-2048Northbeam Ltd€12,400Paid

INV-2047Halden Group€8,950Sent

INV-2046Orbis Retail€3,180Overdue

INV-2045Kestrel Labs€6,720Paid

L9:41
21/10/2026

InvoicesPage.xaml.csAI

public sealed partial class InvoicesPage : Page

{

public InvoicesViewModel Vm { get; } = new();

protected override async void OnNavigatedTo(

NavigationEventArgs e)

=> await Vm.LoadAsync();

}

Senior review · approved

Pipelinemain

Build
Testspassed
Senior review
MSIX signed
Releaseauto-update

Buildto launch

Day 1Week 1Week 2Week 3Live

Ledgerly 1.0 is liveDeployed to 1,240 devicesnow

At a glance

One product. One price, one date.

The essentials, before you book a call.

UDEX builds Windows apps for founders and product teams. Modern Windows apps on .NET and WinUI — fast, secure and ready for enterprise fleets and the Microsoft Store. AI writes the code, tests and CI/CD, while senior engineers own the architecture and review every change.

1 dayFree prototypeNo payment, no commitment

FixedPrice and dateAgreed before we start

100%YoursCode, repository and accounts

Platform: Windows, native .NET
Ships to: The Microsoft Store or your fleet
Stack: C#.NETWinUI 3WPFMicrosoft Store
Quality: Senior review on every change, automated tests, CI/CD

How it works

Idea to production. In three steps.

AI does the heavy lifting. Senior engineers make every decision that matters.

01Day 0
Share the idea
A 30-minute call. We agree on the core flow, the scope and a fixed release date.
02Day 1 → release
AI builds, senior engineers decide
AI writes the code, tests and CI/CD. Senior engineers set the architecture and review every change. Your prototype is ready on day 1.
03Release day
Ship to the Microsoft Store or your fleet
The release goes live, and the code, repository and accounts are handed to you.

Who it’s for

Built for founders and product teams.

Here is where it works best, and where it doesn’t.

Business software

Apps installed across company laptops and desktops.

Teams with legacy WinForms or WPF

Modernise without breaking daily work.

Office-integrated tools

Apps that work with Excel, Outlook and Teams.

Hardware and POS

Printers, scanners and local devices.

Enterprise IT

Silent installs and updates through Intune.

Industry tools

Engineering, finance and healthcare desktop software.

Not the right fit

Mac at the same launch: see Flutter or macOS apps.
Games and 3D engines.
Certified compliance from day one, such as HIPAA or PCI audits.
Open-ended hourly work without a defined first release.

How we work

Six stages, one team.

All services

Pricing

Start free. Ship at a fixed price.

Two steps. The prototype costs nothing, and the release costs exactly what we agree.

Prototype

Free1 day

A working prototype of your core flow to test with users and show investors.

Key screens and the main user flow
Working on real devices and browsers
No payment, no commitment

Get the free prototype

Release

Fixed priceand date, agreed upfront

A production release, shipped to the Microsoft Store or your fleet, that you fully own.

C#, .NET, WinUI 3 and the features agreed on the call
Automated tests, CI/CD and senior code review
Release to the Microsoft Store or your fleet and 100% code ownership

Start with a call

Fixed means fixed. No hourly billing and no surprise invoices: anything new is priced before it is built.

Book a call

Thirty minutes. Then your prototype.

Walk us through the idea, and we will scope the core flow and build your free prototype the next day.

Book a 30-min call

FAQ

Questions, answered.

Straight answers about cost, timing, quality and ownership.

How much does it cost to build a Windows app?

The price is fixed for the agreed scope and set before work starts. You first get a free working prototype of the core flow in 1 day, then a fixed price and release date for the production version.

How long does it take to build a Windows app?

A working prototype takes 1 day. The production release date is agreed upfront and depends on the scope; AI speed with senior engineering makes it much faster than classic development.

WinUI or WPF?

WinUI 3 for new Fluent apps, WPF when you extend an existing app. We recommend one on the call.

Can IT deploy it silently?

Yes. We package with MSIX and support Intune and other management tools.

Can you modernise our old app?

Yes, step by step, keeping it working for your users throughout.

Is the prototype really free?

Yes, with no commitment. After a 30-minute call we build a working prototype of your core flow in 1 day, and then you decide whether to continue to the release.

Will the price go up during the build?

No. The price is fixed for the agreed scope. Anything new you want to add mid-build is priced separately and built only after you approve it.

Who owns the code?

You do, 100%. The source code, repository and accounts are yours, and the release ships to the Microsoft Store or your fleet under your name.

Is AI-written code safe to ship to production?

It ships only after senior review. Senior engineers own the architecture, security and code quality, and automated tests run on every change.

In practice