Simple ERP

A small desktop ERP for a software team: employees, projects, KPI scoring and reports.

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Simple ERP is a Windows desktop app for the people side of a small IT company. It keeps the staff list with salaries and five performance indicators, tracks projects with their schedule, budget and team, turns the indicators into a KPI leaderboard and shows everything on a dashboard.

I wrote the first version in 2018 on .NET Framework with MahApps.Metro and LiveCharts. In 2026 I rebuilt it on .NET 8 to practise a clean MVVM architecture: a UI-independent core with unit tests, a hand-made WPF theme and charts drawn without third-party libraries. The original idea and data model (employees, KPI indicators, ranking, projects) are kept; the bugs of the first version are fixed and listed below.

📸 Screenshots

Employee profile and KPI	Project editor and team

_{The screenshots show the demo data that is created on the first start.}

✨ Features

📊 Dashboard	Headcount, payroll, active projects and average KPI, a team radar chart, projects by status, headcount by position, active projects that need attention and the top performers
👥 Employees	Search, filter by position and sort by name, KPI score, salary or hire date. The editor shows age and tenure, the employee's projects and a live radar chart compared with the team average
🎯 KPI scoring	Five indicators (teamwork, code efficiency, design skills, leadership, project success) are combined into one score weighted by position and graded from Needs attention to Outstanding
🏆 Leaderboard	Standard competition ranking: equal scores share a rank (1, 2, 2, 4)
📁 Projects	Client, status, dates, budget, spending and progress. Assign a team with check boxes and see its monthly cost
🚦 Project health	On track, At risk (progress behind the schedule or spending ahead of progress), Over budget, Overdue, Not started, On hold, Completed
✅ Validation	Messages appear under the fields as you type: required names, e-mail format, age 16–80, hire date not in the future, positive salary, end date after start date, and more
🛡 No lost work	Switching to another record, page or closing the window with unsaved changes asks to save, discard or cancel
📤 CSV export	Employees (with rank and score) and projects (with health and team) as UTF-8 CSV that opens in Excel
💾 Safe storage	One human-readable JSON file, written atomically. A damaged file is moved aside instead of being overwritten
⌨️ Shortcuts	Ctrl+N new record, Ctrl+S save

How the KPI score is weighted

Position	Teamwork	Code efficiency	Design skills	Leadership	Project success
Developer	20%	35%	10%	10%	25%
Designer	20%	10%	35%	10%	25%
QA engineer	25%	25%	10%	10%	30%
Business analyst	25%	5%	15%	20%	35%
Team lead	20%	20%	5%	30%	25%
Project manager	25%	0%	5%	35%	35%

🧱 Tech stack

Area	Technology
Runtime	.NET 8, C# 12 (nullable reference types, file-scoped namespaces, primary constructors, collection expressions)
UI	WPF with custom resource dictionaries (colors, control templates, vector icons), no UI toolkit
Charts	Own RadarChart, BarChart and DonutChart controls drawn in OnRender
Architecture	MVVM with CommunityToolkit.Mvvm source generators, INotifyDataErrorInfo validation, Microsoft.Extensions.DependencyInjection
Storage	System.Text.Json
Tests	xUnit, 155 tests: domain logic, storage, CSV and view-model scenarios with fakes
CI/CD	GitHub Actions: build, test and a self-contained single-file .exe on every push; tagged versions become GitHub releases

🏗 Architecture

All logic, including the view models, lives in SimpleErp.Core, a plain net8.0 library that knows nothing about WPF. It is fully unit-tested and builds on Linux and macOS. The WPF project contains only XAML, chart controls, converters and thin platform services.

flowchart LR
    subgraph App["SimpleErp (WPF, net8.0-windows)"]
        V[MainWindow · Views<br/>Themes · Converters]
        C[RadarChart · BarChart · DonutChart]
        PS[DialogService<br/>ShellService]
    end

    subgraph Core["SimpleErp.Core (net8.0)"]
        VM[ShellViewModel<br/>Dashboard · Employees · Projects · Reports]
        ED[EmployeeEditor · ProjectEditor<br/>INotifyDataErrorInfo]
        S[ErpStore]
        L[KpiCalculator · ProjectAnalyzer<br/>Validators · CsvExporter · DemoData]
        R[(JsonErpRepository<br/>data.json)]
        A[[IDialogService<br/>IShellService]]
    end

    V -- data binding --> VM
    C -- ChartPoint --> VM
    VM --> ED
    VM --> S --> R
    VM --> L
    VM --> A
    PS -. implements .-> A

Loading

Key design decisions:

• One store, write-through. ErpStore holds the only in-memory copy. Every change is applied to a copy of the data, written to disk and only then made live, so a failed write leaves both the file and the UI consistent.
• Editors work on a copy. Editing never touches the stored record until Save, which makes Discard and the unsaved-changes prompt straightforward.
• Validation errors appear when they are useful. A field shows its error once it has been edited, or after a save attempt, so a new, empty form does not start out red.
• Pure domain functions. KPI weighting, ranking and project health are static functions of their input and the current date, so they are trivial to test.
• Why a JSON file and not a database? The data set is small (dozens to hundreds of records) and always read and written as a whole. A single JSON file is human-readable, easy to back up, needs no native SQLite library in the single-file build and lets the tests run anywhere. Storage sits behind IErpRepository, so moving to EF Core and SQLite would only add a new implementation.
• Why own charts? The three charts need a few hundred lines of drawing code. That avoids a charting package (and SkiaSharp's native binaries) and renders identically on every machine.

Project layout

Simple_ERP/
├── src/
│   ├── SimpleErp/                  # WPF application
│   │   ├── Themes/                 # Colors.xaml, Controls.xaml, Icons.xaml: the design system
│   │   ├── Views/                  # Dashboard, Employees, Projects, Reports
│   │   ├── Charts/                 # RadarChart, BarChart, DonutChart
│   │   ├── Converters/
│   │   └── Services/               # DialogService, ShellService
│   └── SimpleErp.Core/             # UI-independent logic
│       ├── Models/                 # Employee, Project, KpiScores, ErpData
│       ├── Services/               # ErpStore, repository, KPI, project health, CSV, demo data
│       ├── Validation/             # EmployeeValidator, ProjectValidator
│       ├── ViewModels/             # shell, pages and editors
│       └── Abstractions/           # IDialogService, IShellService
├── tests/
│   └── SimpleErp.Core.Tests/       # xUnit tests
└── .github/workflows/ci.yml

🛠 What changed compared to the 2018 version

The first version was a single .NET Framework 4.6.1 project. Rebuilding it fixed these problems:

• Editing an employee created a duplicate. ControllerBase.Save updated the existing record and then added it to the list again anyway. The store now replaces records by id.
• The ranking went stale. Ranks were calculated once at start-up from a truncated integer average, were not copied by Clone() and were never recalculated after an edit. Scores and ranks are now calculated from the current data every time, with ties handled explicitly.
• The app depended on the internet. Employees were downloaded from randomuser.me with a blocking request inside the view-model constructor, so the window froze on start-up and the app crashed offline; avatars were loaded from a third-party URL. Demo data is now generated locally and avatars are drawn from initials.
• Nothing was saved. All changes were lost on exit. Data is now stored in %APPDATA%\SimpleERP\data.json.
• Editing text could corrupt it. Text boxes were bound through a converter that prefixed values with Label: and removed all spaces when reading them back, so "New York" became "NewYork". Typing a non-number into the salary silently kept the old value. Fields are now plain inputs with validation messages.
• New employees had no id. A reflection helper filled every empty field with "None", so all new employees shared the id "None" and saving a second one overwrote the first.
• Age and birth date could disagree, because both were stored. Age is now derived from the birth date.
• The KPI chart relied on reflection over compiler-generated backing fields, whose order is not guaranteed. The indicators are now an explicit enum.
• Crashes: the first-letter converter threw on an empty string, and an empty employee list caused an index of -1.
• Projects were placeholders: dates were 01.01.0001, progress was random and employees could not be assigned. Projects now have real dates, budget, spending, a team and a health status.
• Commands were dispatched through a dictionary of magic strings; position names had typos (emloyee); an unused, empty window (sdfsdfsd.xaml) was removed.

🚀 Getting started

Download

Download SimpleERP-*-win-x64*.zip from Releases and run SimpleERP.exe. The framework-dependent build needs the .NET 8 Desktop Runtime; the self-contained one from the CI artifacts does not.

Build from source

Requirements: Windows 10/11 and the .NET 8 SDK (or Visual Studio 2022 with the .NET desktop development workload).

git clone https://github.com/Staery/Simple_ERP.git
cd Simple_ERP
dotnet run --project src/SimpleErp

Run the tests on any OS:

dotnet test tests/SimpleErp.Core.Tests

Build a single-file executable:

dotnet publish src/SimpleErp -c Release -r win-x64 --self-contained -p:PublishSingleFile=true -o publish

Where is my data?

In %APPDATA%\SimpleERP\data.json. Delete the file to start again with fresh demo data.

{
  "schemaVersion": 1,
  "employees": [
    {
      "id": "5e4d0000-0000-4000-8000-000000000000",
      "firstName": "Olivia",
      "lastName": "Bennett",
      "email": "olivia.bennett@simple-erp.example",
      "city": "Remote",
      "position": "projectManager",
      "birthDate": "1974-10-27",
      "hireDate": "2024-06-17",
      "monthlySalary": 9600,
      "kpi": { "teamwork": 66, "codeEfficiency": 24, "designSkills": 43, "leadership": 72, "projectSuccess": 61 }
    }
  ],
  "projects": [ … ]
}

🧪 Tests

tests/SimpleErp.Core.Tests (155 tests) covers:

• KPI: weights add up to 100 for every position, weighting, clamping, grades and competition ranking
• Project health: every status, schedule and budget edge cases, team cost
• Validation: all employee and project rules
• Storage: JSON round trip, readable format, corrupt files moved aside, hand-edited files normalised
• Store: no duplicates on save, removal from teams when an employee is deleted, rollback when writing fails
• CSV: escaping (including spreadsheet formula injection), invariant number formats, UTF-8 with BOM
• View models: filtering and sorting, create/save/delete, the unsaved-changes prompt (save, discard, cancel), navigation guard, keyboard shortcuts, export

🗺 Roadmap

• Time tracking per project and employee
• KPI history with a trend chart
• Import employees from CSV
• Dark theme

📄 License

MIT © 2018–2026 Anton Selkin