Payabl Interview Questions (Feb 10, 2025)
SQL/Database Questions
1. What's the difference between WHERE and HAVING?
Coding Exercise
2. Write payment endpoints in any framework you want (I chose FastAPI)
* Implement POST endpoint (create transaction)
* Implement GET endpoint (retrieve transaction)
* Store data locally (no database needed)
* Note: I asked about idempotency, interviewer said "ignore it for now, but nice you know that"
Security/Authentication
3. How do you protect endpoints?
4. How do you do authorization?
Validation
5. How do you implement validation logic?
Performance/Optimization
6. What would you do if you need to query 10 million rows and it takes too long?
Behavioral Questions
7. What will you do if someone gives you review comments?
8. What challenges have you solved and what do you feel proud about?
DevOps/Docker
9. How do you see logs in Docker?
10. What if you can't attach to the container