WalletX

LiveOpen sourceFull-stack demo

Full-stack FinTech-style wallet demo: P2P transfers, balances, history, and dashboard analytics. MongoDB multi-document transactions enforce ACID semantics so debits and credits stay consistent under concurrency (simulated funds, not real money).

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multi-document transfers: ACID
auth and input validation: JWT + Zod
on any failure before commit: Rollback

Tech stack

React
TypeScript
Tailwind CSS
Framer Motion
Recharts
Node.js
Express.js
MongoDB
Mongoose
MongoDB transactions
JWT
BCrypt
Zod

Overview

WalletX is a full-stack FinTech-style application that simulates real-world wallet operations such as peer-to-peer transfers, balance management, and transaction history. The system is designed with strong consistency guarantees, ensuring that every transfer behaves like a real financial operation.

At its core, WalletX leverages MongoDB multi-document transactions to enforce ACID properties. All transfers are executed atomically using database sessions, preventing partial updates, double spending, or inconsistent balances even under concurrent requests.

What it does

Executes peer-to-peer money transfers with atomic guarantees
Maintains consistent balances across sender and receiver accounts
Stores complete transaction history with audit trail
Provides real-time dashboard with balance and analytics
Implements secure authentication and user management

Technical breakdown

Frontend

Frontend is built with React + Vite using TypeScript, with TanStack Query for server state management and Recharts for analytics. The UI is component-driven with Tailwind and Radix, focusing on responsive and accessible FinTech-style design.

Backend

Backend follows an MVC architecture using Express and Mongoose. Core business logic is implemented in a transfer service that uses MongoDB sessions and multi-document transactions to ensure ACID compliance. JWT handles authentication, while Zod validates all inputs before execution.

Technical challenges

01
Ensuring atomic money transfers
A transfer involves debiting one account and crediting another. Without transactions, partial failures could corrupt balances. This was solved using MongoDB sessions and multi-document transactions to guarantee atomicity.
02
Preventing double spending
Concurrent requests or retries could result in duplicate transfers. The system enforces balance checks and executes all operations within a single transaction scope to maintain consistency.
03
Maintaining consistency under failure
Failures during transfer execution (server crash, validation error) must not leave the system in an invalid state. Transactions ensure automatic rollback on any failure before commit.
04
Keeping transactions performant
Long-running transactions can cause contention in MongoDB. Indexing and minimal query scope were used to keep transactions short and efficient.

Who it is for

Designed for developers and recruiters to demonstrate understanding of real-world financial system design, including transactional integrity, backend architecture, and secure full-stack application development.