Inventory Management system

Overview

Your task is to build a backend service that simulates an inventory management system for a company providing cross-border liquidity services. The company operates liquidity pools in multiple currencies and manages currency transfers for users sending funds between different currencies.

The system will support the following currencies:

• USD, EUR, JPY, GBP, and AUD.

Objective

The key objectives are to create a system that:

• Manages liquidity pools across various currencies.
• Tracks inventory, revenue, and FX rates for each transaction.
• Dynamically rebalances liquidity pools based on transaction data to maintain optimal balances.

Language and Framework:

• Preferred: Node.js with TypeScript.
• Alternative: Any language or framework of your choice is accepted.

Requirements

1. API Endpoints

   • Transfer Request: POST /transfer

     • Accepts a transfer request from a sender to a receiver, converting currency X to currency Y.
     • Uses the FX rate to calculate the amount in currency Y and apply a transaction margin.
     • Immediately debits the amount in Y from the liquidity pool and records it.
     • Adds revenue based on the applied margin.
     • Takes into account currency-specific settlement times.
       • Note: In the real world, settlement times typically depend on the country and payment rails. For this exercise, however, we’ll simplify by making settlement times dependent on the currency instead.

   • FX Rate Update: POST /fx-rate

     • Receives mock FX rates between supported currencies.
     • Updates the stored FX rates for use in transfer calculations.
     • The mock script, mockFxRateSender.js, should be used to send rate updates to this endpoint every 3-5 seconds.
       • Example payload from the script:

         {"pair":"AUD/JPY","rate":"82.6666","timestamp":"2024-11-11T11:22:18.123Z"}
         

     • The script will occasionally send extreme fluctuations (5% chance of a 5-10% change) to simulate market volatility.

2. Liquidity pool rebalancing

   • Periodically rebalance liquidity between pools to maintain optimal balances.
   • Takes into account transaction volume and send/receive imbalances.
   • Ensures each pool is adequately funded to meet anticipated demand.
   • Track available liquidity in each currency pool in real-time.

3. Revenue Calculation

   • Track revenue by calculating the margin on each transaction.

4. Foreign Exchange Rates

   • Store FX rates and allow historical lookups for use in transfer and revenue calculations.

5. Data Persistence

   • Use reliable data storage to maintain inventory levels, transactions, FX rates, and revenue.
   • Ensure atomicity and resilience to outages for each transaction.

6. Additional Requirements:

   • Use configuration files or environment variables for adjustable parameters, such as margin percentages, currency settlement times, and rebalance frequencies.
   • Ensure logging and error handling, especially for scenarios with missing liquidity or FX rates.

Initial Balances per Currency

• USD: 1,000,000
• EUR: 921,658
• JPY: 109,890,110
• GBP: 750,000
• AUD: 1,349,528

Currency Settlement Times

Each currency has a predefined settlement time, simulating the delay for funds to be confirmed in liquidity pools. These settlement times are specified in seconds for easy testing:

• USD: 3 seconds
• EUR: 2 seconds
• JPY: 3 seconds
• GBP: 2 seconds
• AUD: 3 seconds

Submission

Please submit your work in a GitHub repository. Either set the repository to public, or, if you prefer to keep it private, add the following users as collaborators: nelsontky, SphereLaboratories, santosmarco, audreyleow and aur42.