Status: 7+ years of experience in backend development
Position: SSE at Walmart
Location: Bangalore, India
Date: April 2024
Total Process Time: Approximately 1 to 1.5 months

Karat Round (1 hour):

One coding question with a lengthy input and expected output, such as an array of strings of strings. The logic was simple, but I don’t remember the exact question. It was of medium or easy to medium difficulty.
Five theoretical system design questions. Try to provide as many points as possible. For example, to improve system latency, you can mention adding cache, CDN for static content, adding database indexes, etc. Each question has 5 minutes allotted, and HR will share a format for the same.
Result: Selected
1st Technical with Atlassian LLD or Design (1 hour):

Atlassian often asks about designing a rate limiter, which was the case for me as well (x requests in y time). I proposed a moving window approach, but I was removing all requests from the queue within the time window. The interviewer suggested processing only one request, reducing the time complexity from O(windowLength) to O(1). The interview went well, and the interviewer was very friendly. We finished a bit early and talked about common hobbies, etc.
2nd Technical with Atlassian or DS:

In this round, they asked about a voting algorithm where each person gets votes in order (e.g., (ABC) -> A having 3 votes, B 2, and C 1). The goal was to return the most voted person. This question is common in many Atlassian rounds. Then, they asked a similar version, focusing on how I would handle the algorithm, follow the Open-Closed Principle, and add a function to the interface. The coding rounds were not hard; just follow standard design processes.
3rd HLD:

Designed a service to get the most viewed or liked page. Discussion points included:
How to maintain a list of likes. Should I maintain viewed IDs or just a count? Pros and cons.
Handling a scenario where a new page becomes the most liked next year while still showing users the previous year's top page. I proposed using a NoSQL database mapped to each day with a list of pages, but the interviewer preferred Cassandra DB, stating we wouldn’t consider this year's data. I was unsure how to solve this, resulting in a pass with a P40 ranking, which decreased my interest in Atlassian.
4th Managerial:

I expected a mix of technical and behavioral questions, but it was entirely behavioral. The interviewer expected STAR format answers, and I felt I didn't perform well. Overall, it was a simple round.
5th Values:

Focused on Atlassian's five values. Prepare a story for each value and answer in the STAR format. Nothing special.
Overall, I did well in the Karat round and the first two technical rounds but was weak in the HLD and managerial rounds. The main rejection came from the managerial round, but I was approved in the values round. In my experience, cracking Atlassian isn't that hard; you don't need to solve all of LeetCode and lots of DS questions. Prepare some design patterns, stay confident, stay calm during interviews, and have a sip of water if needed. However, I don't like their practice of downgrading to lower roles, which they do often. I also heard they revoked offers for freshers, so I was a bit skeptical during the interview.

Request for Community:
I am good at DS and have passed DS rounds in all my interviews but have failed in HLD and sometimes in LLD. Any tips for improvement?