Expenses Rust Backend

A Rust reimplementation of the Expenses backend that powers registration, authentication, and transaction tracking. It keeps the original PostgreSQL schema so it can coexist with the TypeScript version while showcasing the same domain but with Axum + SeaORM + Redis.

Stack

• Axum for the HTTP layer
• SeaORM for database access (PostgreSQL)
• redis-rs for session storage
• Argon2 password hashing, Tokio runtime and tower-http tracing/cors helpers

Configuration

The service reads the following environment variables (you can use .env during development):

Variable	Description	Default
DATABASE_URL	PostgreSQL connection string	required
REDIS_URL	Redis connection string	required
HOST	Interface to bind (e.g. 0.0.0.0)	0.0.0.0
PORT	HTTP port	8080
SESSION_TTL_SECS	Session TTL in seconds	21600 (6 hours)

Make sure the PostgreSQL database already contains the tables created by the TypeScript project's migrations (users, categories, transactions, ...). The Rust service reuses the same schema so both stacks can talk to the same data.

Running locally

cd expenses-rs
cargo run

With the environment configured you should see a Starting HTTP server log and the API will be available at http://localhost:8080 (or the host/port you set).

Available endpoints

All responses follow { result: boolean, data?: T, message?: string, errorCode?: number }. Endpoints that require a session expect the Authorization: Bearer <token> header using the token issued by POST /api/auth/login.

Method & Path	Description
GET /health	Simple liveness probe
POST /api/users	Register a new user (email, firstName, lastName, password)
POST /api/auth/login	Authenticate, receive { token, user } and set the session cookie (sessionID by default)
POST /api/auth/logout	Invalidate the current session
GET /api/users/me	Return the authenticated user
GET /api/categories	List categories of the authenticated user
POST /api/categories	Create a category { transactionType, name, note? }
GET /api/categories/:categoryId	Fetch a single category
DELETE /api/categories/:categoryId	Delete a category. Add ?deleteTransactions=true to also remove its transactions
GET /api/transactions	List transactions for the user with optional month, year, categoryId, transactionType, limit filters
POST /api/transactions	Create one or multiple transactions. Accepts either categoryId, the legacy categoryName + categoryNote, or the nested { category: { name, type?, note? } } payload together with the financial fields (transactionType, amount, currency, month, year, etc.)
GET /api/transactions/:transactionId	Fetch a transaction by id
DELETE /api/transactions/:transactionId	Soft delete a transaction
GET /api/transactions/balance	Aggregate balances grouped by transaction type and currency
GET /api/transactions/months	Returns the months available per year for the user
GET /api/transactions/total-saving	Total amount saved (type SAVING)

Example payloads

POST /api/users
{
  "email": "user@example.com",
  "firstName": "Jane",
  "lastName": "Doe",
  "password": "supersecret"
}

POST /api/auth/login
{
  "email": "user@example.com",
  "password": "supersecret"
}

POST /api/transactions
Authorization: Bearer <token>
{
  "transactionType": "EXPENSE",
  "amount": 50.5,
  "currency": "USD",
  "month": "JANUARY",
  "year": 2025,
  "note": "Groceries",
  "category": {
    "name": "Food",
    "type": "EXPENSE"
  }
}

POST /api/transactions
Authorization: Bearer <token>
{
  "transactions": [
    {
      "transactionType": "INCOME",
      "amount": 3000,
      "currency": "USD",
      "month": "FEBRUARY",
      "year": "2025",
      "categoryId": "<existing-category-id>"
    },
    {
      "transactionType": "EXPENSE",
      "amount": 120.55,
      "currency": "UYU",
      "month": "FEBRUARY",
      "year": 2025,
      "categoryName": "Utilities"
    }
  ]
}

GET /api/transactions?month=JANUARY&year=2025
Authorization: Bearer <token>

Next steps

• Add persistence for the remaining resources (financial goals, shopping lists, etc.)
• Ship richer validation/middleware, OpenAPI docs and integration tests
• Package with Docker to mirror the TypeScript deployment story