Building a Local-First Tax Prep Tool with .NET & Windows App SDK

ReturnReady — Thu, 02 Apr 2026 15:30:56 +0000

Tax season is a universal pain point. But as a developer, I noticed something interesting: the stress doesn't come from calculation—it comes from disorganization.
People jump into filing software before they have all their documents. They switch tabs, search emails for W-2s, and panic about missing AGI from last year.
The Technical Challenge
Most tax tools today are cloud-based. They require uploading sensitive PII (Personally Identifiable Information) to third-party servers. In 2025, that feels unnecessary.
I decided to build ReturnReady with a Local-First Architecture:

Stack: .NET Desktop Runtime + Windows App SDK
Privacy: All parsing happens on the user's machine. No cloud uploads.
Output: Vendor-neutral exports (PDF/HTML/CSV) that work with ANY filing software.

Why Separation Matters
I believe Preparation and Filing are two distinct disciplines:

Preparation = Organization, verification, inventory.
Filing = Calculation, submission.

When you mix them, you get friction. ReturnReady forces you to stop and organize before you start filing.
Current Status
We're live on Microsoft Store with W-2 support. 1099 and other forms are in the roadmap.
For Fellow Devs
If you're curious about the implementation (WinUI 3, local file parsing, etc.), feel free to reach out. I'd love to discuss the technical decisions behind building a privacy-first finance tool on Windows.
🔗 Go to Microsoft Store

Disclaimer: This is a preparation tool only. It does not file taxes.

DEV Community: ReturnReady

Building a Local-First Tax Prep Tool with .NET & Windows App SDK