Confluent Senior Software Engineer Interview Experience — A Linux-Heavy Super Day With No Feedback

Confluent·Software Engineer·Jan 2026
OnsiteTechnical ScreenSenior+medium

Role: Confluent - Senior Software Engineer - Cloud Traffic

Screen: look up a word in a given file — each line of the document is one sentence. First find a word in the document, then as a follow-up find a phrase/sentence in it. Just talked through the approach at a high level; optimizing with a hashmap was enough. The feedback said I needed hints.

VO (super day) — Specialty: intense grilling on Linux, networking, and container knowledge, with heavy follow-ups. Time was very tight. Questions included things like:

How a Linux command gets executed

How ls, pwd, ip, ifconfig work under the hood

How directories and files are opened in Linux

Linux permissions and user groups

How the directories under / work, what /proc is

Linux kernel

Container vs. VM comparison, and when to use each

Coding 1: A variant of a problem whose name is garbled/illegible in the original post — using an LRU-style approach to implement get, put, getAverage on a data stream. A high-frequency question on this forum. Got through it bug-free, quickly.

Coding 2: implement tail -n, another high-frequency question on this forum. After I laid out my approach I was basically left on my own, and I realized this was turning into a stress test. In the end I didn't fully understand how to use file.seek, and I didn't handle the edge case of reading the file with chunked reads correctly, which caused a bug. I tried switching to seeking character by character but ran out of time to implement it. No hints, no feedback the entire time. My own prep notes on interview questions.

System Design: TinyURL, another high-frequency question on this forum. Two interviewers. The problem itself didn't leave much to talk about, but I got hit with frequent "why/why not" follow-ups. Not much pressure though. The scaling part should have been fine too.

BQ: They dug into my projects, mainly using my project history to assess leadership, customer success, and team growth. I got stuck on the customer success question because it required an external customer — all my work had been internal-facing, and the one external-facing project I had was excluded because I'd already talked about it earlier, so I was forced to talk about an unpolished result from a previous startup instead. No interaction the whole time, just rapid-fire question and answer.

Summary: my systems-level knowledge wasn't solid enough — I need to study specifically for what this role requires. I was careless about prepping for the high-frequency questions and for BQ storytelling.

Published

Curated and edited by PracHub

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Interview at a glance

Company
Confluent
Role
Software Engineer
Level
Senior+
Rounds
Technical Screen → Onsite
Difficulty
medium
Interview date
Jan 2026
Questions from this interview
5 questions

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