Delta Board

A lightweight, privacy-first retrospective tool for teams to collaboratively reflect on their work.

Philosophy

• Lightweight - Minimal dependencies, fast loading, simple architecture
• Minimalist - Two columns: What Went Well and Delta (what to adjust)
• Single Purpose - Built specifically for retrospectives, nothing more
• Privacy Aware - No server-side data storage, all data lives in your browser

How It Works

1. Create a board - Generate a unique URL instantly, no signup required
2. Share with your team - Send the URL to participants (up to 20 people)
3. Collaborate in real-time - Add cards, vote on items, discuss improvements
4. Export and close - Download as Markdown when done

Key Features

• Real-time collaboration via WebSockets
• Persistent local storage - Your boards survive browser restarts
• Voting system - Prioritize what matters most
• Card ownership - Edit your own cards, vote on anyone's
• Export to Markdown - Archive your retrospectives
• No accounts - Anonymous, instant access
• Dark theme - Follows OS preference, with manual toggle
• Installable PWA - Works offline, install on any device

Project Structure

delta-board/
├── src/
│   └── DeltaBoard.Server/       # C# server (serves API + static files)
│       ├── wwwroot/             # Client web application
│       │   ├── index.html
│       │   ├── 404.html
│       │   ├── css/
│       │   │   ├── shared.css
│       │   │   └── styles.css
│       │   └── js/
│       │       ├── app.js
│       │       └── theme.js
│       ├── Program.cs
│       ├── BoardHub.cs
│       └── DeltaBoard.Server.csproj
├── tests/
│   ├── DeltaBoard.Server.Tests/ # C# xUnit tests
│   └── client/                  # JavaScript Vitest tests
├── docs/
│   ├── DESIGN.md               # Technical design documentation
│   ├── LIFE_CYCLE.md           # Board phases and transitions
│   ├── PROTOCOL.md             # WebSocket protocol specification
│   └── STYLE.md                # Visual identity and brand guidelines
├── package.json                # JS test tooling
├── vitest.config.js
└── delta-board.sln

Getting Started

Run the Server

cd src/DeltaBoard.Server
dotnet run

The server starts at http://localhost:5123 and serves both the web application and WebSocket API.

Run Tests

# Server tests (C#)
dotnet test

# Client tests (JavaScript)
npm install
npm test

# Browser regression tests (Chromium desktop, mobile, and breakpoint views)
npx playwright install chromium
npm run test:browser

# Cross-browser behavior checks
npx playwright install firefox webkit
npm run test:browser:cross

The browser suite starts the ASP.NET application, exercises multi-participant workflows, checks accessibility and offline behavior, and compares reviewed visual baselines. Linux CI is the authority for visual comparisons; macOS runs skip screenshot assertions. To create candidate Linux baselines after the workflow is available on the default branch, run:

gh workflow run ci.yml --ref <branch> -f update_snapshots=true

Download and review the visual-baselines-linux artifact before committing changed images. Run npm run test:browser:update directly only in a matching Linux environment. When bootstrapping the workflow before dispatch is available on the default branch, the first pull-request run stores missing Linux snapshots in the browser-failure artifact.

Run with Docker

# Build the image
docker build -t delta-board .

# Run it
docker run -p 8080:8080 delta-board

The server starts at http://localhost:8080. The container listens on port 8080 by default (configurable via ASPNETCORE_HTTP_PORTS).

CI

GitHub Actions runs on every push to main and on pull requests:

• Build the .NET server
• Run .NET server tests (xUnit)
• Run JavaScript client tests (Vitest)

Releases

When a GitHub release is published, a workflow builds a multi-platform Docker image (linux/amd64, linux/arm64) and pushes it to GHCR.

Release type	Example tag	Container tags
Pre-release	v0.1.0-preview.1	0.1.0-preview.1
Stable	v1.0.0	1.0.0, latest

# Pull and run a specific version
docker run -p 8080:8080 ghcr.io/yoannchaudet/delta-board:1.0.0

Documentation

• docs/DESIGN.md - Architecture, tech stack, and deployment
• docs/LIFE_CYCLE.md - Board phases (forming/reviewing) and transitions
• docs/PROTOCOL.md - WebSocket protocol and message schemas
• docs/STYLE.md - Visual identity, colors, and brand guidelines

License

MIT