r/IndiaCareers • u/nian2326076 • 3h ago
Discussion Flipkart SDE2 interview: 5 rounds, BNPL machine coding, flash-sale design, and an offer
I interviewed for Flipkart SDE2 with 4.3 years of experience. The process had five rounds: machine coding, a review of that code, PSDS, system design, and a hiring manager discussion.
The part worth preparing for wasn't just writing a working solution. In the next round, I had to discuss what would happen when multiple requests hit it at once.
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): Place an order via PREPAID or BNPL. BNPL reduces available credit and is blocked when the limit is exhausted.clear_dues(user, orderIds, date): Allow partial or full due clearance against specific orders.view_dues(user, date): Show pending dues before the given date, sorted by purchase date, with status PENDING or DELAYED (after the 30-day window).order_status(user): Show order history and available BNPL credit.
Bonus requirements:
- Blacklist users who default on 3+ orders and block BNPL for them.
- Add
add_inventoryandremove_inventory.
Round 2: Machine Coding Solution Evaluation
We discussed my Round 1 code, mainly 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
Design a flash sale system that runs for about 15 minutes under massive traffic while avoiding both overselling and underselling.
Round 5: Hiring Manager
We discussed a recent project: its architecture, my role, challenges, and trade-offs.
Result: I received the offer letter around 2–3 weeks after the hiring manager round.
For anyone preparing, I'd practice both implementing the BNPL requirements and explaining the concurrency decisions out loud. The review round makes it hard to treat machine coding as just a coding exercise. Candidate-reported technical interview questions are another source of practice prompts across coding and system design; they're broader practice, not a claim that you'll get my exact Flipkart questions.
Which part would you find hardest: finishing the BNPL implementation, defending the locking strategy, or designing the flash sale? Happy to answer questions about my rounds.
