Zepto

Role: Software Engineer I (SDE-1)

College: B.Tech Tier 1 (Top 10 NIT)

Interview Date: September 2024

Interview Type: Full-Time

Result: Rejected (Initially selected, then rejected by HM)

Difficulty: Medium

Rounds: 4 rounds

Topics Asked: Data Structures, Algorithms, Low-Level Design, High-Level Design, Database (Indexing, ACID, CAP theorem), Message Queues, Caching, OOP Principles, Project Discussion, Behavioral

Experience:

The candidate, with 14 months of experience as an SDE1 at a startup, mailed their resume to HR. The process involved 4 rounds.

Round 1: DSA

This round included two coding problems.

• First and Last Occurrence of an Element problem.
• Finding a binary string of length N that doesn't occur in a given array of distinct binary strings of the same length.

Additionally, the interviewer asked questions related to Indexing in Databases, Message Queues, and various caching policies based on the candidate's projects.

Round 2: Low-Level Design (LLD)

The candidate was asked to design an e-commerce application.

• Database schema design.
• Identification of important services.
• API endpoints design.
• Stock management (quantity, product expiry, updates).
• Handling discount coupons (adding new, clubbing coupons).
• Discussion on design patterns and OOP principles used.

Questions were also asked about the database schema and system interactions.

Round 3: Hiring Manager (HM) Round

The round began with an introduction and discussion about current projects.

• Technical questions: Explanation of Indexing (and its differences between MongoDB and MySQL), ACID properties and CAP theorem, drawbacks of indexing, how the candidate made their current project scalable.
• Behavioral questions: Explanation of metrics provided in the resume (e.g., reduced costs by 15%), learning approach for new technologies, motivation for joining Zepto, current location, and recent learnings.

The interview concluded, and the candidate initially received an email confirming selection. However, two days later, HR informed that the HM had updated the status to rejected.