Phenom Senior Software Engineer interview questions

- The interview began with an in-depth discussion of your project architecture, focusing on the motivation for introducing a **BFF layer** and using **GraphQL**. - A significant part of the discussion centered on your implementation of the **Transactional Outbox Pattern**, exploring consistency guarantees and asynchronous event publishing. - The DSA section included two standard interview problems: **Number of Islands** and **Longest Substring Without Repeating Characters**, with emphasis on your approach and reasoning rather than just code. - The most substantial part of the interview was a **system design discussion** around a flight booking system. The interviewer continuously evolved the scenario, asking how you would handle race conditions, optimistic vs. pessimistic locking, Redis, versioning, and concurrent seat booking. - Additional scenarios explored failures after successful payment, requiring discussion of **Saga**, **Transactional Outbox**, **Kafka retries**, **DLQs**, and why certain approaches are unsuitable for critical booking workflows. - Unlike many of your other interviews, this one was highly interactive. The interviewer guided the discussion, challenged assumptions, and expected you to reason through evolving scenarios rather than recall framework-specific details. - Overall, this round assessed **backend engineering fundamentals, distributed systems thinking, concurrency handling, and problem-solving ability**, with relatively little emphasis on Java API trivia or Spring Boot internals.