PayU Credit Backend Engineer Interview: Rounds, Questions and Preparation

What the job involves

Backend engineers in neobanking, lending, and insurtech build and maintain the APIs, services, and data pipelines that power loan origination, credit underwriting, repayment schedules, KYC verification, and insurance policy issuance. Day to day, you will write server-side code, design database schemas, integrate with payment gateways, credit bureaus, and identity verification providers, and ensure transaction data is accurate, secure, and auditable. You will also debug production issues, optimise query performance, and collaborate with product, risk, and compliance teams to ship features that handle real money and sensitive financial data.

Role and technical knowledge

1. 1

   Walk me through how you would design a REST API endpoint to create a loan application.

   Cover HTTP method, request and response JSON, validation of fields like PAN, Aadhaar, income, and loan amount, and storing the application with a status such as PENDING or UNDER_REVIEW.

2. 2

   What is idempotency and why is it critical when handling loan repayments or payment callbacks?

   Explain that the same request can be retried without duplicating a payment or loan disbursement, and mention using an idempotency key stored in a database or cache.

3. 3

   How would you model a borrower, loan account, and repayment schedule in a relational database?

   Describe tables for customer, loan, and EMI schedule with foreign keys, and mention indexes on loan_id and due_date for fast lookups.

4. 4

   What steps would you take to secure sensitive customer data such as bank account numbers and credit scores in a lending backend?

   Cover encryption at rest and in transit, masking in logs, role-based access control, and not storing raw card or Aadhaar data unless required.

Practical scenarios and problem solving

1. 5

   A payment gateway callback for a loan EMI is received twice due to a network retry. How do you ensure the customer is not charged twice?

   Use an idempotency key or transaction reference, check if the payment is already recorded, and return a success response without reprocessing.

2. 6

   Your credit bureau API call is timing out during peak hours, causing loan applications to fail. What do you do?

   Suggest retries with exponential backoff, circuit breaker, caching recent bureau pulls where allowed, and async processing with a queue so the user gets a pending status.

3. 7

   How would you debug a bug where some loan repayment schedules show an incorrect last EMI amount?

   Check rounding logic, interest calculation method, date handling across months, and write a unit test with a known loan amount and tenure to reproduce.

4. 8

   You need to add a new insurance product to an existing policy issuance service. How do you approach it without breaking current products?

   Discuss backward-compatible API changes, feature flags, separate configuration per product, and thorough regression tests before rollout.

Behavioural and situational questions

1. 9

   Tell me about a time you had to learn a new technology or domain quickly for a project or internship.

   Use a specific example, describe your learning approach, and connect it to delivering a working result within a deadline.

2. 10

   Describe a situation where you found a bug or error in your own work. How did you handle it?

   Show ownership by admitting the mistake, explaining how you fixed it, and what process you added to prevent similar issues.

3. 11

   In a fintech team, you may disagree with a product manager about a feature that affects compliance. How would you handle it?

   Emphasise listening, asking questions, presenting data or regulatory concerns clearly, and escalating through the right channel if needed.

4. 12

   Why do you want to work in neobanking, lending, or insurtech rather than a general software company?

   Connect personal interest in financial inclusion, digital payments, or credit access with the impact of reliable backend systems in this sector.

HR and fresher-focused questions

1. 13

   You have worked on a college project using a different stack. How will you ramp up on our backend stack?

   Mention transferable concepts like APIs, databases, and version control, and give a concrete plan such as documentation, small tasks, and code reviews.

2. 14

   Where do you see yourself in two years as a backend engineer in a fast-growing fintech?

   Show realistic growth from owning small services to designing components, and express interest in deepening domain knowledge in lending or insurance.

3. 15

   How do you prioritise when you have multiple tasks such as fixing a production bug, writing tests, and attending a team meeting?

   Explain assessing impact and urgency, communicating with your lead, and blocking time for critical work while keeping the team informed.

4. 16

   Are you comfortable working with strict deadlines and compliance requirements in a regulated financial environment?

   Answer yes with an example of handling pressure, and show awareness that accuracy and auditability matter more than speed in fintech.