FinanceChain: A Robust Financial API

FinanceChain is a powerful financial API crafted using Elixir and Phoenix, designed with a focus on blockchain principles and the Open Telecom Platform (OTP). This architecture allows for exceptional concurrency and fault tolerance, making it suitable for various banking operations.

Overview & Motivation

The primary goal of FinanceChain is to deliver a reliable API that can seamlessly handle essential banking tasks such as deposits, withdrawals, and transfers. This project tackles the inherent challenges of managing financial accounts with high levels of concurrency, reliability, and data integrity.

By implementing a system that treats each account as an independent, concurrent process (a GenServer), FinanceChain encapsulates its own mini-blockchain. This design facilitates parallel account operations while leveraging OTP's supervisory capabilities for fault tolerance.

Architectural Philosophy

FinanceChain is grounded in the following principles:

• Concurrency with GenServers: Each financial account is managed by its own FinanceChain.BlockChain.AccountServer GenServer, enabling concurrent operations without contention.
• Blockchain per Account: Each AccountServer maintains a dedicated blockchain, streamlining state management and localizing transaction history.
• Supervision Trees (OTP): The robustness of the system is ensured through OTP's supervision capabilities, which automatically restart failed processes to maintain high availability.
• Registry for Process Discovery: Efficiently maps account_ids to their corresponding AccountServer process IDs (PIDs) for quick lookup and communication.

Core Components

FinanceChain comprises several essential modules:

• FinanceChain.Application: Defines the supervision tree for critical components and manages the startup of processes such as Registry and DynamicSupervisor for accounts.
• FinanceChainWeb.EventController: Serves as the API gateway, handling incoming HTTP requests for various banking operations and translating them into corresponding blockchain functions.
• FinanceChain.BlockChain: Acts as the public API for interactions with the financial system, orchestrating operations such as getting balances, deposits, withdrawals, and transfers.
• FinanceChain.BlockChain.AccountServer: A GenServer managing the blockchain for individual accounts and maintaining transaction history.
• FinanceChain.BlockChain.Wallet: Defines the data structure for a financial transaction, including details for funds movement.
• FinanceChain.BlockChain.Block: Defines the structure of a blockchain block, encompassing transaction data and cryptographic links to previous blocks.
• FinanceChain.BlockChain.Chain: Manages the blockchain data structure, providing functionalities to manipulate it.

API Endpoints & Usage Examples

FinanceChain exposes several endpoints:

• Reset System State POST /reset

  • Resets the entire system, clearing all accounts and transaction histories.
  • Response: 200 OK

• Get Account Balance GET /balance?account_id={id}

  • Retrieves the current balance for a specified account.
  • Response: 200 OK with the balance.

• Deposit Funds POST /event (type: deposit)

  • Adds funds to an existing account or creates a new account.
  • Response: 201 Created with the updated balance.

• Withdraw Funds POST /event (type: withdraw)

  • Withdraws funds from an account.
  • Response: 201 Created with updated balance on success.

• Transfer Funds POST /event (type: transfer)

  • Transfers funds between accounts.
  • Response: 201 Created with updated balances for both accounts.

Areas for Future Improvements

To enhance production readiness, several improvements are suggested:

• Implement atomic transfers to guarantee consistency during fund movements.
• Integrate data persistence methods to safeguard account data.
• Enhance cryptographic features for secure transaction signatures.
• Develop user authentication and authorization mechanisms.