Hi Leetcoders, you can read my interview experience with Ixigo for the role of SDE 2 - Backend.

One thing to note: HR has explicitly mentioned the first round would be DSA, but interviewer asked Redis and Kafka related production scenarios only.

Q1. Design a race-condition-safe user signup system

You need to design a signup flow where:

• Phone number is mandatory and must be unique
• Multiple concurrent requests for the same phone number can hit different servers/pods
• System should not create duplicate users

Interviewer agreed solution: Redis atomic lock

Q2. Efficient Redis access with prefix

You have:

• Millions of keys in Redis
• Only a prefix of keys is known (e.g., lock_phone_xxxxxxxx)
• Need to fetch ~5000 matching keys efficiently

Note: Avoid expensive operations like full scans or regex
Interviewer agreed solution: Redis Sorted Set

Q3. Data migration
System B uses multiple MySQL tables.
System A uses a single Mongo collection.
Migrate System B's data to System A

You need to:

• Migrate existing (historical) data
• Handle incoming live traffic simultaneously
• Ensure no data loss or duplication
• Maintain backward compatibility during migration

Interviewer agreed solution: Event stream DB logs using debezium to Kafka topics, use kafka idempotency to avoid duplicates.

Although I answered all the questions but not exactly what interviewer was looking for.

Result: Rejected

~Anonymous