Payment integration architecture in HLD - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Architecture

intermediate

Identify the correct component for handling payment authorization

In a payment integration system, which component is primarily responsible for verifying the payment details and obtaining approval from the payment gateway?

A Payment Gateway Adapter

B Transaction Logger

C User Interface Module

D Payment Authorization Service

💡 Hint

Think about which part talks directly to the payment gateway to approve payments.

The Payment Authorization Service handles the verification and approval process by communicating with the payment gateway.

❓ scaling

intermediate

Scaling payment processing for high transaction volume

Your payment system needs to handle thousands of transactions per second during peak hours. Which approach best supports this scaling requirement?

A Implement horizontal scaling with multiple stateless payment processing instances behind a load balancer

B Use a single monolithic server with a powerful CPU

C Store all transactions in a single database table without sharding

D Process payments synchronously on the client side

💡 Hint

Think about how to distribute load evenly and avoid bottlenecks.

Horizontal scaling with stateless instances and a load balancer allows the system to handle many transactions concurrently and scale out easily.

❓ tradeoff

advanced

Choosing between synchronous and asynchronous payment processing

What is a key tradeoff when choosing asynchronous payment processing over synchronous processing in a payment integration system?

A Asynchronous processing reduces system complexity but slows down transaction throughput

B Asynchronous processing improves user experience but increases complexity in handling payment status updates

C Synchronous processing allows delayed payment confirmation to improve scalability

D Synchronous processing eliminates the need for transaction logging

💡 Hint

Consider how user experience and system complexity are affected by processing style.

Asynchronous processing lets users continue without waiting but requires careful handling of payment status updates, increasing complexity.

🧠 Conceptual

advanced

Ensuring security in payment integration architecture

Which practice is most effective to protect sensitive payment data during transmission in a payment integration system?

A Use HTTPS with TLS encryption for all communication between client and server

B Store payment data in plain text to speed up processing

C Send payment details via email for record keeping

D Disable authentication to reduce latency

💡 Hint

Think about how data should be protected when moving over the internet.

Using HTTPS with TLS encryption ensures data is encrypted during transmission, protecting it from interception.

❓ estimation

expert

Estimating storage needs for transaction logs

Your payment system processes 10,000 transactions per minute. Each transaction log entry is approximately 1 KB. Estimate the storage needed for transaction logs for 30 days.

A 43.2 GB

B 4.32 GB

C 432 GB

D 4320 GB

💡 Hint

Calculate total transactions per month and multiply by size per entry.

10,000 transactions/min × 60 min/hr × 24 hr/day × 30 days = 432,000,000 transactions. At 1 KB each, total storage = 432,000,000 KB = 432 GB.