Questions that have appeared at PayPal for an engineering (Case Study) interview.

1. System Design

Question: How would you design a system to handle the massive amount of transactions processed by PayPal daily?

Question: How would you ensure the security of user transactions and personal information in the system you designed?

Question: Discuss an approach to design a microservice architecture for PayPal’s transactional system.

2. Scalability

Question: How would you scale PayPal's system to accommodate an influx of new users during peak shopping seasons like Black Friday or Cyber Monday?

Question: Can you describe a time when you had to scale a system you were working on, and how you went about it?

Question: How would you handle database sharding in a high volume transactional system like PayPal?

3. Performance Optimization

Question: How would you improve the performance of PayPal's system without compromising security?

Question: What are some effective strategies for optimizing the latency of a high-throughput system like PayPal?

Question: Provide an example of a time you had to optimize a system's performance. What was the problem and how did you solve it?

4. Data Engineering

Question: How would you design a system to efficiently process and analyze PayPal's massive amount of transactional data?

Question: Discuss an approach to manage real-time data processing in PayPal.

Question: How would you ensure data consistency in a distributed system like PayPal?

5. Disaster Recovery

Question: How would you design a disaster recovery plan for PayPal's system?

Question: What are the key aspects to consider while creating a failover strategy for PayPal?

Question: Discuss an example of a situation where you had to recover from a system failure. What steps did you take?