Software Engineering Fundamentals Interview Questions
Practice 603 real Software Engineering Fundamentals interview questions for 2026. Covers core coding, data structures, complexity analysis, debugging, and implementation best practices — real questions from actual interviews with detailed solutions to support focused interview preparation. This category tests the engineering basics interviewers rely on to predict on-the-job performance: correct and efficient algorithms, clean and maintainable code, complexity trade-offs, edge-case reasoning, and the ability to turn requirements into a working implementation under time pressure. Expect heavy weighting at companies like Amazon, Google, and OpenAI, where fundamentals often gate candidates before system design or product rounds. To prepare, prioritize timed problem practice that enforces clear communication, complexity justification, and test-case coverage; drill common data structures and complexity patterns until they become second nature; and rehearse coding on a whiteboard or shared editor to simulate real loop conditions.

"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 Cache with Hit Counts
This question evaluates a candidate's competence in system design, data structures, concurrency, and observability by requiring a key-value cache that...

Explain worker state machine load balancer design
You are designing a lightweight load balancer for a Python-based backend service that dispatches tasks to a pool of worker processes. Describe how you...

Debug a Project Assignment Codebase
This question evaluates debugging, state management, test-driven troubleshooting, data filtering correctness, and the ability to maintain a public API...
How to triage slow service alerts
A production alert indicates that a web service is experiencing high latency or slow responses. As an SRE, describe how you would triage, investigate,...
Implement a Stoppable Producer–Consumer System in C++
Implement a Stoppable Producer–Consumer System in C++ Design and explain a C++ implementation with three classes: Storage, Factory, and Consumer. Cons...
Java and Object-Oriented Design Fundamentals
This question assesses mastery of software engineering fundamentals across object-oriented design, Java collections, and the Spring framework. It test...
Design a Checkers Game Simulator
Design and partially implement an object-oriented simulator for a two-player checkers-like board game. Requirements: - The game is played on an 8 x 8 ...
Design an extensible expense rule evaluator
This question evaluates system-design and API/interface skills for rule engines, focusing on data modeling, extensibility, maintainability, and rule/r...
Implement a Single-Node Priority Pub/Sub
Implement a simplified in-memory publish-subscribe system that runs on a single machine. The system should support users subscribing to topics with a ...
Search Words and Phrases in a Large Line-Oriented File
Search Words and Phrases in a Large Line-Oriented File A text file contains one sentence per line and may be much larger than memory. Design an API th...
Explain what happens when opening a website
When a user types https://www.amazon.com into a browser and presses Enter, what happens end-to-end? Cover the major steps across the browser, DNS, TCP...
Design an object-oriented queue and compare implementations
Design an object-oriented queue and compare implementations You are asked to design an object-oriented Queue abstraction and discuss how it can be imp...
How to root-cause Wi‑Fi chip stops after 30 minutes
You are running automated tests on a Wi‑Fi chip. The chip transmits normally at the beginning, but after about 30 minutes it stops transmitting (no si...
Explain Modern Python Features and Ecosystem
This question evaluates a candidate's expertise in modern Python language features, the surrounding ecosystem of libraries and frameworks, GUI toolkit...
Implement an Extensible Chatbot App
Implement a ChatApp class that processes user messages and routes them to bot responders. The system must support multiple bot types, and the design m...
Explain Core SRE Practices
In a Site Reliability Engineer interview, explain the core principles and daily practices of SRE. Discuss topics such as service-level indicators and ...
Design a multi-threaded synchronous log writer
This question evaluates a candidate's understanding of concurrent programming, durable I/O, synchronization primitives, ordering guarantees, and syste...
Design an object-oriented parking lot system
Design an object-oriented model for a parking lot management system. Requirements: - The parking lot has multiple levels; each level has multiple park...
Implement tap-to-infect color grid on iOS
iOS Grid Infection (Flood Fill) Design Goal Build an iOS app that displays a 2D grid with two colors. When the user taps a cell, all 4-directionally a...
Write SQL to sum city population by name
You have four relational tables: - country(country_id, name) - state(state_id, country_id, name) - city(city_id, state_id, name) - zip(zip_code, city_...