Backend Engineer Software Engineering Fundamentals Interview Questions
Practice 19 real Software Engineering Fundamentals interview questions for Backend Engineer roles. From companies including Bytedance, Instacart, Reddit, Arm, Chime.
"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."
Build a CSV-to-JSON Classification Service
Build a CSV-to-JSON Classification Service Build a backend service in stages. First, an HTTP request supplies a server-visible CSV path and the servic...
Implement a Synchronized First-Available Seat Allocator
Implement a Synchronized First-Available Seat Allocator Implement the core of a concurrent ticket-booking service with N seats numbered 1 through N. S...
Backend Fundamentals Deep Dive: MySQL Internals, Redis, and the HTTP/HTTPS Request Lifecycle
This question tests deep backend engineering knowledge across three core domains: MySQL InnoDB internals (logging, indexing, isolation), Redis persist...
Find Bugs in an LRU Cache
Find Bugs in an LRU Cache The Java class below is intended to implement a least-recently-used cache. A successful get and every put should make the ke...
Design a Thread-Safe Bounded Blocking Queue
Design a Thread-Safe Bounded Blocking Queue Design a fixed-capacity FIFO queue shared by multiple producer and consumer threads. Provide operations eq...
Debug and Improve a Load Balancer
Debug and Improve a Load Balancer Clarifying Questions to Ask - Is the load balancer a single process exercise or a distributed production service? - ...
Evolve Cursor Pagination Without Breaking Clients
Debug bidirectional cursor pagination when many transactions share the same timestamp, then add amount sorting without breaking old clients. Define st...
Design Tennis Scoring with Pluggable Rules
Design Tennis Scoring with Pluggable Rules Prompt Design a small scoring component for one tennis game between two players. It must record which playe...
Design a Cloud-Agnostic Upload Adapter
Design a provider-neutral upload library that hides cloud SDK differences without flattening every provider capability into one interface. Cover strea...
Design a Train Ticket Booking System
This question evaluates a backend engineer's competency in object-oriented design, SOLID principles, API and service design, data modeling, concurrenc...
Explain Backend Fundamentals and AI Tooling
This question evaluates understanding of core backend and AI tooling topics including operating system concepts (processes vs threads), networking (TC...
Design browser history across tabs
This question evaluates a candidate's ability to design stateful data structures and manage per-tab navigation history, testing competencies in data s...
Clarify and Implement Search Filters for a Library Table
Clarify and Implement Search Filters for a Library Table An existing library-management application shows a book table that users find too long and di...
Debug Metrics Computed Before Filtering
Debug Metrics Computed Before Filtering A metrics page accepts filters and returns both matching rows and summary metrics. Users report that the rows ...
Explain project decisions and trade-offs
Pick one project you worked on and walk through the key technical decisions behind it. Why did you choose that architecture, design, or technology sta...
Explain concurrency and distributed fundamentals
This question evaluates understanding of concurrency and synchronization in multithreaded Java, Java hashing and equals/hashCode semantics, garbage co...
Design an Elevator Control System
Design an object-oriented elevator control system for a building with multiple floors and multiple elevators. The system should support: - Hall reques...
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...
Explain timing and testability concepts
For a digital implementation or backend-focused interview, explain the following concepts: 1. What are setup time and hold time? 2. How does clock ske...