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."
Exception Handling in a RESTful Service with @ControllerAdvice
This question evaluates a candidate's understanding of centralized error handling in RESTful API design, specifically using framework-level cross-cutt...
Troubleshoot a production server outage
You are the on-call engineer responsible for a production server for the next several days. Discuss how you would approach the following: - How would ...
Design a Todo List Object Model
This question evaluates object-oriented design and API modeling skills, focusing on domain modeling, class responsibilities, encapsulation, and design...
Use AI Responsibly During SQL Pair Programming
Prompt The reported pair-programming round included several SQL exercises and explicitly evaluated both collaboration and the candidate's use of AI. T...

Design CSV upload endpoint with GPT classification
This question evaluates backend engineering skills including HTTP API design, multipart file handling, CSV parsing and serialization, local JSON persi...
Plan a Safe Repository-Wide Identifier Migration
Plan a Safe Repository-Wide Identifier Migration You have a very large repository whose internal variables and function names use snake case. A conver...
Compare arrays, linked lists, hash tables, trees
Answer the following computer-science fundamentals questions: 1) What are the time complexities (Big-O) of common sorting algorithms (e.g., bubble sor...
Demonstrate effective AI-assisted coding workflow
In an interview where you are allowed to use an AI coding assistant, you are given a large scoped task (e.g., implementing a TCP chat server). The int...
Data Pipeline Reliability, Backfills, and Spark Optimization
You are interviewing for a senior data engineering role on an analytics and observability team. The interviewer asks a sequence of practical questions...
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...
Fetch and Rank Articles from a Paginated API
Fetch and Rank Articles from a Paginated API Implement top_articles(limit) against a paginated HTTP endpoint. Page p returns JSON with data and total_...
Reviewing a Freight-Scheduler Codebase: Bugs, Data Structures, and Concurrency
You have just finished implementing process_order(...) inside a large provided codebase for a freight-scheduling system (this is the review stage of a...
Explain Spark Execution and Optimization
You are interviewing for a Data Engineer role. In a 30-minute discussion on production data engineering, the interviewer probes how well you understan...
Debug an Angular UI from User Reports
Debug an Angular UI from User Reports You receive an existing Angular frontend code sample and several concrete user-reported failures. Reproduce each...
Robust Selenium Code to Extract Text from Two Elements
This question evaluates practical knowledge of browser test automation, specifically writing reliable Selenium code that reads text from web elements ...
Design and Solve a Rotatable Jigsaw Puzzle
Design and Solve a Rotatable Jigsaw Puzzle Design the classes and a solve operation for a rectangular jigsaw puzzle. You are given all pieces, but not...
Find frequent IPs from a huge file
You are given a very large log file (too large to fit in memory). Each line contains an IPv4 address (e.g., 203.0.113.7). Design an approach to answer...
Architecture and Data-Scaling Trade-offs
This question evaluates a candidate's grasp of software architecture and database scaling trade-offs, covering microservices versus monolithic design ...
Alternating Die-Roll Game: Optimal Accept/Reject Strategy
Two players, A and B, play the following game with a fair 21-sided die whose faces are labeled with the integers $-10, -9, \ldots, 9, 10$ (one integer...
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...