💳 Wallet System (Go + gRPC + JWT + YooKassa SDK)

A backend system written in Go using a microservice architecture with gRPC communication.
The project simulates a simple financial system with authentication via jwt, payments via YooKassa, and balance management.

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🛠 Technology Stack

🧠 Architecture Overview

The system consists of gRPC module + main backend API which both work in grpc client and server mode simultaneously for creating and confirming payment:

• Main Backend (HTTP + Auth + API + Users with balance) ↓ (gRPC)
• Payment Service (YooKassa integration and balance + transactions) (gRPC)

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🧱 Services

🟢 Main Backend

Responsible for:

• User registration & login
• JWT authentication (access + refresh tokens)
• HTTP API (Fiber)
• Creating payment requests
• User balance management

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🟡 Payment Service (gRPC)

Responsible for:

• Creating payment sessions via YooKassa
• Handling payment webhooks
• Tracking payment status
• Communicating payment result to main backend

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👤 User Flow

• Registration:
  User sends: POST /api/v1/new:

{
    "first_name":"John",
    "last_name":"Pork",
    "username": "Johny1821",
    "email":"[email protected]",
    "password":"hello1212"
}

Reply:

{
    "message": "successfully registered"
}

• Login:
  User sends: GET /api/v1/login:

{
    "email":"[email protected]",
    "password":"hello1212"
}

Reply:

{
    "id": "cf074995-c549-40d5-b7d7-da59318cf967",
    "first_name": "John",
    "last_name": "Pork",
    "username": "Johny1821",
    "balance": 0,
    "email": "[email protected]"
}

and tokens in cookies:
refresh_token: eyJhbGciOiJIUzI1NiIs...5iYcU
access_token: eyJhbGciOiJIUzI1NiIs...-cFhC7U

💳 Payment Flow

1. User sends: POST /api/v1/auth/payment { "price": 129 } with cookies

2. Main backend sends request via grpc to payment module

3. Payment module sends request to yookassa and return response:

{
    "result": "https://yoomoney.ru/checkout/payments/v2/contract?orderId=318d8984-000f-5000-b000-14607dcab9c2"
}

4. After confirming the payment in your personal yookassa account webhook updates payment status in payment Service.
   Then Payment Service triggers main backend via gRPC

5. User sends: GET /api/v1/auth/get with cookies Reply:

{
    "id": "cf074995-c549-40d5-b7d7-da59318cf967",
    "first_name": "John",
    "last_name": "Pork",
    "username": "Johny1821",
    "balance": 129,
    "email": "[email protected]"
}

🚦 Getting Started

Prerequisites

• Docker & Docker Compose
• Go 1.21+ (for local development)

Configuration

1. Clone the repository:

   git clone https://github.com/SH1roV12/BalanceApp.git

2. Environment Setup: Define your .env file.

3. Run docker compose

docker compose up

4. Start ngrok

ngrok http HTTP_YOOKASSA_PORT 

and paste the link in your personal account in yookassa

5. Use routes:

POST	/api/v1/new	
POST	/api/v1/login	
GET	/api/v1/users	
GET	/api/v1/refresh	
POST	/api/v1/auth/payment	JWT Middleware(send with cookies)
GET	/api/v1/auth/get	JWT Middleware(send with cookies)