ArionWallet Backend System Development

ArionWallet is a backend system designed to model how real digital wallets and transaction platforms work, with a strong focus on correctness, auditability, and long term scalability.

To build a backend foundation for a fintech style application that can safely manage wallet balances, transactions, and ledger entries while remaining frontend agnostic and extensible.

Handling money introduces complexity beyond standard CRUD APIs:

Balance consistency must be guaranteed

Every transaction must be traceable

State transitions must be predictable

The system must be designed for future compliance, fraud checks, and audits

A naive design would quickly break under real-world usage.

I designed ArionWallet as a modular monolith using Domain Driven Design principles, separating core concerns like users, wallets, transactions and ledger entries.

Key outcomes:

Clear transaction lifecycle (PENDING → SUCCESS / FAILED)

Double-entry ledger ensuring every balance change is auditable

API-first design that can support any frontend or client

Clean domain boundaries that support future growth

Java & Spring Boot

RESTful API design

PostgreSQL for transactional data

Redis for performance and state support

Domain-Driven Design (DDD)

Modular monolith architecture

Transactional integrity and state management