Flipkart SDE2 Interview Experience (September 2026) | Selected

Position: SDE2 Experience: 4.3 Yrs

Sharing my Flipkart interview experience across 5 rounds. Hope it helps anyone preparing.

Round 1: Machine Coding (BNPL System)

Design and implement a Buy Now Pay Later (BNPL) system for Flipkart from scratch, with working code.

Core requirements:

• seed_inventory: Load products (name, count, price) into an in‑memory store
• view_inventory: Show current inventory
• register_user: Register a user with an initial BNPL credit limit
• buy(user, items, payment_method, date): Order via PREPAID or BNPL. BNPL reduces the credit limit and is blocked if the limit is exhausted
• clear_dues(user, orderIds, date): Partial or full due clearance against specific orders
• view_dues(user, date): Pending dues before the given date, sorted by purchase date, with status PENDING or DELAYED (30‑day window crossed)
• order_status(user): Order history plus available BNPL credit limit

Bonus:

• Blacklist users who default on 3+ orders and block BNPL for them
• add_inventory / remove_inventory

Round 2: Machine coding round solution evaluation

A discussion on my Round 1 code, mainly around concurrency: two threads buying the last unit, keeping credit limits consistent under concurrent BNPL orders, locking strategy, and extensibility.

Round 3: PSDS

• Find the kth element in two sorted arrays (binary search, O(log(min(m, n))))
• Zigzag traversal in a binary tree

Round 4: System Design

Problem: Design a flash sale system running ~15 minutes under massive traffic, avoiding both overselling and underselling.

Round 5: Hiring Manager

Discussion on my recent project: architecture, my role, challenges, and trade‑offs.

Result:

Got the offer letter after around 2-3 weeks after the HM interview round.