Invoice Manager — .NET Desktop Application
Arkadiusz Staniek
Invoice Manager
Invoice Manager is a release-ready, local-first Windows business application implementing a complete quotation-to-payment workflow with transactional numbering, immutable historical snapshots, auditable payments, reproducible PDFs, and automated persistence testing.
.NET 10 · WPF · MVVM · Clean Architecture · EF Core · SQLite
Project status:v1.0.0is published in the public GitHub repository. The self-contained Windows package, release notes, screenshots, and presentation assets are available with the release.
What It Solves
Freelancers and small businesses often duplicate customer, pricing, VAT, and payment data across spreadsheets and document templates. That approach makes status tracking fragile and can silently change historical output after a company address, customer record, service price, VAT rate, or logo is edited.
Invoice Manager keeps the workflow and its business history in one local SQLite database. It supports one company profile and EUR without requiring a cloud account, and deliberately stops short of accounting or ERP scope.
Demo Workflow
Run a safe fictional dataset against a new database with
--demo. The seeder refuses non-empty business databases, so evaluation data cannot be mixed accidentally with existing records.Key Engineering Challenges
Historical snapshots
Issued documents own persisted issuer, customer, line-item, and logo snapshots. Later edits affect new documents only, keeping historical PDFs reproducible.
Transactional numbering and conversion
Yearly quote and invoice numbers are allocated only on first persistence. Sequence updates, aggregate persistence, and accepted-quote conversion are atomic, with database uniqueness constraints as a final safeguard.
Recorded and auditable payments
Partial and full payments derive outstanding balances and invoice status. Records are immutable; an incorrect payment is voided once with a reason and UTC timestamp instead of rewriting history.
Deterministic time
Business dates and UTC audit instants are separate concepts. An injected clock makes expiration, overdue, payment, and audit behavior repeatable in automated tests.
Implemented Features
Customer create, view, edit, archive, and search workflows
Product and service create, edit, deactivate, and search workflows
Local SQLite persistence with automatic migrations
Single-company profile and document defaults
Quotation creation, editing, item management, search, status tracking, automatic expiration, and yearly numbering
Invoice creation, editing, item management, search, Draft/Sent/Cancelled lifecycle controls, and independent yearly numbering
One-time atomic conversion from an accepted quotation to a linked invoice
Recorded partial and full payments with outstanding balances, Paid and Overdue status, and overpayment protection
Immutable payment history with reasoned voiding instead of editing or deletion
Quote and invoice PDF export to a user-selected location
Persisted historical company logos for reproducible document output
Dashboard KPIs, recent invoices, and a 12-month payment-revenue chart
Transactional fictional demo data that can only be loaded into an empty database
Keyboard navigation, accessibility labels, empty states, validation feedback, and versioned release packaging
Screenshots
Dashboard Quotation editor
Technology
Area Technology Runtime .NET 10 LTS Language C# Desktop UI WPF UI pattern MVVM with CommunityToolkit.Mvvm Persistence Entity Framework Core 10 and SQLite PDF PDFsharp 6.2.4 Hosting and DI Microsoft.Extensions.Hosting Testing xUnit CI GitHub Actions on Windows
Architecture
The application follows a layered architecture:
The Domain project has no dependencies. Business logic belongs in Domain or Application, never in WPF views, view models, or persistence code. See Architecture and the decision records.
Quality and Testing
Evidence Result Automated tests 97 passed / 0 failed Domain 43 tests Application 26 tests Infrastructure 28 tests Release build 0 warnings / 0 errors NuGet vulnerability audit 0 known vulnerable dependencies EF Core model No pending migrations Windows package Verified self-contained win-x64 build
Infrastructure coverage includes concurrent document numbering, transaction rollback, one-time quote conversion, competing payment registration, database constraints, migrations, snapshot persistence, safe demo seeding, and PDF generation. Representative application screens and PDFs are also reviewed visually.
Repository Layout
The detailed layout is documented in Architecture.
Running the Application
Prerequisites
Windows 10 or Windows 11
.NET 10 SDK, version
10.0.302 or a compatible later patchRestore, Build, and Test
Run the Desktop App
On startup, the application creates its directories and applies pending EF Core migrations automatically. The current UI includes the complete company-to-payment workflow, PDF export, and live financial dashboard reporting.
Explore with Fictional Demo Data
Use a fresh or explicitly isolated database:
The demo seeder refuses to run when any business data already exists. Its fictional companies, contacts, identifiers, and
.example email addresses are safe for screenshots and evaluation.Build the Windows Release Package
The script creates a self-contained
win-x64 folder and ZIP under artifacts/release.Local Data
Runtime data is stored under
%LocalAppData%/InvoiceManager:Generated PDFs are exported separately to a location selected by the user.
Documentation
Engineering Decisions
Nine accepted ADRs document the major choices: Clean Architecture, WPF/MVVM, SQLite, first-save numbering, historical snapshots, recorded payments, explicit date/time policy, auditable payment voiding, and PDFsharp. See the Architecture Decision Records.
Project Status and Release
All seven milestones are complete. The verified
v1.0.0 Windows x64 package and release notes are published on GitHub. See the completed Roadmap.License
A project license has not been selected yet. Until a license file is added, all rights are reserved.
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Posted Aug 12, 2026
Built a production-ready Windows app for the full quote-to-payment workflow, using Clean Architecture, SQLite, PDF export, CI and 97 automated tests..
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