System Design Question: Bank Transaction Analysis System
Problem Statement
You are designing a system that pulls user bank transactions from external financial institutions and analyzes them based on predefined rules. The system should allow users to connect their bank accounts, fetch transaction data, and apply custom rules for categorization, fraud detection, and spending analysis.
Key Requirements:
- Bank Account Integration
- Users should be able to connect multiple bank accounts via third-party APIs.
- The system should do an initial pull whenever a new user is added to the system.
- The system should periodically fetch the latest transactions.
- Transaction Storage & Processing
- Store fetched transactions in a database.
- Ensure efficient retrieval and processing of large amounts of transaction data.
- Rule-Based Analysis
- Apply predefined rules to classify transactions (e.g., “If a transaction is > $2000 and international, flag as high-risk”).
- Rules should be configurable and scalable.
- Notifications & Reporting
- If a transaction violates a rule, trigger an alert.
- Scalability & Performance
- The system should be able to handle a growing number of users and transactions.
This is a system design interview focused on building a transaction analysis platform for bank data. A strong solution should cover third-party bank integrations, initial and periodic transaction sync, durable storage, a configurable rule engine for classification and risk detection, and an alerting/reporting pipeline. The main discussion points are scalability, efficient processing of large transaction volumes, and reliable incremental updates.
