Twilio

Role: L3 (Software Engineer Level 3)

College: Not Specified

Interview Date: November 2024

Interview Type: Full-Time

Result: Offer

Difficulty: Medium-Hard

Rounds: 4 rounds

Topics Asked: Data Structures (Stack), Algorithms, System Design (API design, DB choices, scalability, concurrency, batching requests), Behavioral

Experience:

This candidate had 7 years of experience and interviewed for an L3 position in Bengaluru in November 2024.

Round 1 (Coding)
This round involved two problems where working modular code was expected.

• Problem 1: Design a custom stack structure that supports standard stack operations while efficiently tracking both the minimum and maximum elements at any given time. Implement `CustomMinMaxStack()`, `insert(int value)`, `getMin()`, `getMax()`.
• Problem 2: Design a Java class that takes requests and sends them to an API endpoint. The class should batch requests once the number of piled requests exceeds a maximum size. A constraint was that a request could only be held for a maximum certain duration, after which it should be sent immediately without waiting for the next batch.

Round 2 (Design)
The task was to design an 'Accounts System' that would be integrated with multiple third-party services. The discussion focused on API specifications, database choices, scalability, and concurrency management. Code was not expected; the discussion was around the approach and how thread and asynchronous operations would work.

Round 3 (HM - Hiring Manager)
This round involved standard behavioral questions, mostly scenario-based and related to past experiences.

Round 4 (Coding)
The problem was similar to the LeetCode problem "Minimum Knight Moves."

Overall Experience: The candidate found the interview process to be good, with transparent and thoughtful HR. The rounds were wrapped up within a week, and cumulative feedback was taken. An offer was extended.