Backend Engineer Interview Questions
Practice 43 real interview questions for Backend Engineer roles. From companies including Bytedance, Harvey, Tesla, Roku, Arm. Covers Coding & Algorithms, System Design, Software Engineering Fundamentals, Behavioral & Leadership.
"I got asked a hardcore MCM DP question and I saw it on PracHub as well. Solved that question in 5 minutes. Without PracHub I doubt I could solve it in 5 hours. Though somehow didn't get hired, perhaps I guess I solved it too fast? /s"
"Believe me i'm a student here jn US. Recently interviewed for MSFT. They asked me exact question from PracHub. I saw it the night before and ignored it cause why waste time on random sites. I legit wanna go back and redo this whole thing if I had chance. Not saying will work for everyone but there is certainly some merit to that website. And i'm gonna use it in future prep from now on like lc tagged"
"10 years of experience but never worked at a top company. PracHub's senior-level questions helped me break into FAANG at 35. Age is just a number."
"I was skeptical about the 'real questions' claim, so I put it to the test. I searched for the exact question I got grilled on at my last Meta onsite... and it was right there. Word for word."
"Got a Google recruiter call on Monday, interview on Friday. Crammed PracHub for 4 days. Passed every round. This platform is a miracle worker."
"I've used LC, Glassdoor, and random Discords. Nothing comes close to the accuracy here. The questions are actually current — that's what got me. Felt like I had a cheat sheet during the interview."
"The solution quality is insane. It covers approach, edge cases, time complexity, follow-ups. Nothing else comes close."
"Legit the only resource you need. TC went from 180k -> 350k. Just memorize the top 50 for your target company and you're golden."
"PracHub Premium for one month cost me the price of two coffees a week. It landed me a $280K+ starting offer."
"Literally just signed a $600k offer. I only had 2 weeks to prep, so I focused entirely on the company-tagged lists here. If you're targeting L5+, don't overthink it."
"Coaches and bootcamp prep courses cost around $200-300 but PracHub Premium is actually less than a Netflix subscription. And it landed me a $178K offer."
"I honestly don't know how you guys gather so many real interview questions. It's almost scary. I walked into my Amazon loop and recognized 3 out of 4 problems from your database."
"Discovered PracHub 10 days before my interview. By day 5, I stopped being nervous. By interview day, I was actually excited to show what I knew."
"I recently cleared Uber interviews (strong hire in the design round) and all the questions were present in prachub."
"The search is what sold me. I typed in a really niche DP problem I got asked last year and it actually came up, full breakdown and everything. These guys are clearly updating it constantly."
Design a Distributed File System
Design a distributed file system for a cloud service — a POSIX-like storage layer that internal applications and external customers use to store and r...
Explain Backend Fundamentals and AI Tooling
You are interviewing for a backend engineering summer internship on a content-safety team (ByteDance / TikTok). This is the technical first round: the...
Design a Real-Time Chess Service
Design an online chess service that supports real-time, two-player games. Users should be able to create or join a game, make legal moves, and see the...
Design Scalable Notification Rate Limiter
Design a production-grade rate limiter for notification sending that enforces limits at three levels of an organizational hierarchy. The system expose...
Fix the Broken Search Filter in a Book Catalog API
Fix the Broken Search Filter in a Book Catalog API A small book-management web app lets users search a library catalog. The frontend sends the user's ...
Solve Bracket Matching and Tree Width
Solve both coding problems below. Problem 1: Validate Balanced Brackets Given a string s containing only the characters (, ), {, }, [ and ], determine...
Determine If One Binary Tree Is a Substructure of Another
Given two binary trees A and B, determine whether B is a substructure of A. B is a substructure of A if there exists some node in A such that the subt...
Backend Fundamentals Deep Dive: MySQL Internals, Redis, and the HTTP/HTTPS Request Lifecycle
This is a backend-fundamentals rapid-fire round covering MySQL internals, Redis internals, and the HTTP/HTTPS request lifecycle. Work through each par...
Design a secure document vault
Design a secure document vault product similar to a cloud repository for sensitive files. The system should allow authenticated users to upload, store...
Find First Anagram Occurrence
Given two strings text and pattern, return the starting index of the first substring in text that is an anagram of pattern. If no such substring exist...
Design a Train Ticket Booking System
Machine-coding exercise, 90 minutes. Design and implement a train ticket booking system. The implementation should be close to working code and should...
Design a Rental Marketplace Backend
Design the backend for a large vacation-rental marketplace similar to Airbnb. The system should support: - A home page that shows popular destinations...
Convert IPv4 Ranges to CIDR Blocks
Implement a function that summarizes a consecutive IPv4 address range using the smallest possible list of CIDR blocks. You are given: - start_ip: a va...
Explain reliability and runtime fundamentals
You may be asked several short technical-fundamentals questions such as: - In a Kafka-based batch consumer, how would you prevent a batch from being p...
Design a high-throughput ad exchange
Design an ad exchange that handles roughly 175,000 bid requests per second. Publishers send impression opportunities to the platform, and demand-side ...
Explain concurrency and distributed fundamentals
A backend fundamentals round covered the following topics: 1. Multithreading in Java: Suppose multiple threads update a shared counter and a shared ma...
Resolve conflict across teams
Describe a time when you had to coordinate between two teams that were in conflict or seriously misaligned. What caused the disagreement, how did you ...
Implement Popular and Ranked Voting
You are given ranked ballots in aggregated form. Each key is an ordered tuple of candidate names representing one voter's preference from highest to l...
Implement Notification Rate Limiter
Implement should_send_notifications(user_id, timestamp) -> bool. You are given two mappings: - each user_id belongs to exactly one team_id - each team...
Describe conflict and proudest work
You may be asked behavioral questions such as: - Tell me about a time you had a conflict with a teammate or partner team. What happened, how did you h...