LoExch - Limit Order Exchange

A simplified cryptocurrency exchange matching engine built with Laravel and Vue.js.

Features

• Limit Orders: Place buy/sell orders for BTC and ETH against USD
• Order Matching: Full-match algorithm with deterministic ordering
• Real-time Updates: Pusher-based broadcasting for instant UI updates
• Commission System: Maker-taker fee model (0.5% maker, 1.0% taker)
• Atomic Transactions: Race-safe balance and asset management

Quick Start (DDEV - Recommended)

DDEV provides a containerized development environment with all dependencies pre-configured.

Install DDEV: https://ddev.readthedocs.io/en/stable/users/install/

git clone <repository-url>
cd LoExch
ddev start
ddev composer setup

Configure Pusher credentials in .env, then access the app at https://loexch.ddev.site

SSL Certificate Warning? Run mkcert -install to trust DDEV's local certificates. See Configuring Browsers.

Setup on Host (Alternative)

System Requirements

• PHP 8.3+ with extensions: bcmath, pdo_mysql
• Composer 2.x
• Node.js 18+ with npm
• MySQL 8+

Installation

git clone <repository-url>
cd LoExch
composer setup

Configure database and Pusher credentials in .env, then:

php artisan serve

Configuration

After setup, configure the following in .env:

Pusher (Required for real-time features)

BROADCAST_CONNECTION=pusher
PUSHER_APP_ID=your-app-id
PUSHER_APP_KEY=your-app-key
PUSHER_APP_SECRET=your-app-secret
PUSHER_APP_CLUSTER=your-cluster

Database (Host only - DDEV auto-configures)

DB_CONNECTION=mysql
DB_HOST=127.0.0.1
DB_DATABASE=loexch
DB_USERNAME=root
DB_PASSWORD=

Test Accounts

After seeding, the following accounts are available:

Email	Password	USD Balance	Assets	2FA
alice@example.com	password	$50,000	1 BTC, 10 ETH	Enabled
bob@example.com	password	$100,000	2 BTC, 20 ETH	No

2FA Demo: In local environment, use code 111111 for two-factor authentication.

Order Matching

Order matching is triggered externally, not automatically. Use the artisan command:

# DDEV
ddev artisan orders:match

# Host
php artisan orders:match

Or via API:

curl -X POST https://loexch.ddev.site/api/internal/job \
  -H "Authorization: Bearer YOUR_INTERNAL_JOB_SECRET" \
  -H "Accept: application/json"

Artisan Commands

Command	Description
php artisan internal:secret	Generate INTERNAL_JOB_SECRET
php artisan orders:match	Trigger order matching

API Endpoints

Method	Endpoint	Auth	Description
GET	/api/profile	Sanctum	Get user balance and assets
GET	/api/orders?symbol=BTC	Sanctum	Get open orders for orderbook
GET	/api/user/orders	Sanctum	Get user's order history
POST	/api/orders	Sanctum	Create a limit order
POST	/api/orders/{id}/cancel	Sanctum	Cancel an open order
POST	/api/internal/job	Bearer Token	Trigger order matching

Commission Model

Party	Fee Rate	Description
Maker	0.5%	The resting order in the orderbook
Taker	1.0%	The incoming order that triggers the match

Both fees are deducted in USD. Buyers lock volume × 1.01 upfront to cover worst-case fees; excess is refunded at settlement.

Testing

# DDEV
ddev artisan test

# Host
php artisan test

Development

# DDEV
ddev npm run dev

# Host
composer run dev

License

MIT License - Free to use, modify, and distribute.