Spiko Tricount

A fullstack expense-sharing application built as a practical case for Spiko's software engineering interviews.

Context

This project is a "Tricount" application (similar to Tricount or Splitwise) that allows users to track shared expenses and settle debts using EUTBL tokens (Spiko tokens).

Features

Authentication

• Sign up with email/password
• Sign in
• Log out

Tricount Management

• Create a new tricount instance (expense group)
• Invite users to join a tricount

Expense Tracking

• Add expenses to a tricount
• Specify who paid and how the expense should be split
• View expense history

Settlement

• Automatic computation of refunds/balances between participants
• Settle debts using EUTBL tokens (Spiko tokens)

Tech Stack

This is an Nx monorepo containing:

• App (app/): React frontend application
• Server (server/): Node.js backend API built with esbuild
• Database: PostgreSQL 16

Getting Started

Option 1: GitHub Codespaces (Recommended)

The fastest way to get started is using GitHub Codespaces:

1. Click the "Open in GitHub Codespaces" badge above
2. Wait for the environment to build (2-3 minutes on first launch)
3. Once ready, run pnpm nx run-many -t dev to start the development servers

Everything is pre-configured: Node.js, pnpm, PostgreSQL, and VS Code extensions.

Option 2: Local Development

Prerequisites

• Node.js LTS (v24.x)
• pnpm
• Docker (for PostgreSQL database)

Database Setup

Start the PostgreSQL database:

docker compose up -d

This starts a PostgreSQL instance with:

• Host: localhost
• Port: 5432
• Database: spiko_tricount
• User: postgres
• Password: postgres

To stop the database:

docker compose down

Installation

pnpm install

Development

Run all projects in watch mode:

pnpm nx run-many -t dev

This starts:

• App: http://localhost:4200 (React frontend)
• Server: http://localhost:3000 (API backend)

Run a specific project:

pnpm nx serve server

Build

npx nx run-many -t build

Testing

npx nx run-many -t test

Linting

npx nx run-many -t lint

Project Structure

app/          # React frontend application
server/       # Node.js backend API (DDD architecture)
  src/
    domain/         # Business entities, repository interfaces
    application/    # Use cases, application services
    infrastructure/ # Database, repositories, migrations
    presentation/   # HTTP handlers, API routes
packages/     # Shared packages
libs/         # Shared libraries

Useful Commands

Command	Description
npx nx graph	Visualize project dependencies
npx nx affected -t build	Build only affected projects
npx nx affected -t test	Test only affected projects

Interview Instructions

Please refer to the instructions provided by your interviewer for specific requirements and evaluation criteria.

License

MIT