American Express

Role: Engineer II

College: Not Specified

Interview Date: Not Specified

Interview Type: Full-Time

Result: Not Specified

Difficulty: Medium-Hard

Rounds: 3 rounds

Topics Asked: Data Structures, Algorithms (Combination Sum), Machine Coding (React), Project Deep Dive, Java (Stream APIs, Functional Interfaces), JavaScript, React (latest features), High-Level Design (Payment Gateway, UPI), Behavioral Questions

Experience:

This LeetCode Discuss experience is for an Engineer II role at American Express for a candidate with 2.5 years of experience. The post is from February 2025.

Round 1: Technical - DSA & Machine Coding
The DSA question asked was the "Combination Sum problem." The machine coding challenge involved React: "Build a carousel with data fetching" and "Implement 5-second delay per item, with pause & play functionality."

Round 2: Technical - Java, JS, React
This round started with a deep dive into the candidate's projects, discussing design, optimizations, and challenges. Java Stream APIs were a focus, with two coding problems on order of operations, forEach, and terminal operations. Functional Interfaces like Supplier and Predicate, and their general usage, were also discussed. Questions on React covered its latest version features and updates. Additional Java & JS questions were also posed.

Round 3: Techno-Managerial
This round involved a discussion on High-Level Design (HLD), specifically for a payment gateway. Discussions also included UPI and how redirects happen from a gateway back to an application. Behavioral questions were also part of this round.