wtf is banking_backend?

This project is a sample backend for a simple banking system, built with Node.js. It is meant as a learning example rather than something you would put into production as is. It covers the core pieces a bank app needs behind the scenes: user accounts, money transfers between accounts, a ledger that records every credit and debit, and email notifications when things happen. Under the hood it uses Express to handle web requests, MongoDB with Mongoose to store data, JWT tokens for login sessions, and bcrypt to hash passwords so they are never stored in plain text. Users can register, log in, and log out through simple API routes. Once logged in, they can create an account, list their accounts, and check an account balance, which is calculated by adding up all the ledger entries tied to that account rather than storing a balance number directly. Money transfers work through a transactions route where you specify the sending account, the receiving account, and an amount. Each transfer includes a unique key so that if the same request is sent twice by accident, it will not double charge anyone. Behind the scenes, the transfer uses a database transaction to make sure both the debit and credit entries are written together or not at all, which keeps the books balanced even if something fails partway through. Every transaction and login attempt triggers an email using Gmail, set up through Google's OAuth login system rather than a plain password, with setup instructions included in the project's docs folder. The README is upfront that this is a demo project, not something ready for real customers. It calls out that hardcoded secrets should be removed, proper input validation should be added, and that the project needs testing and secure deployment practices before anyone would trust it with real money. For someone learning how banking backends handle logins, ledgers, and safe money transfers, it is a clear, well documented example to read through and experiment with.