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 Key-Value Store with Hit Counting
Design a Key-Value Store with Hit Counting Design an in-memory key-value store together with a hit-counter capability. The phrase "hit counter" is amb...
Design a Multi-Producer Multi-Consumer Circular Buffer
Design a Multi-Producer Multi-Consumer Circular Buffer Design a fixed-capacity circular buffer shared by multiple producer and consumer threads. Produ...
Build a Real-Time Event Feed Dashboard
Build the state and component logic for a React event-feed dashboard. Styling is out of scope. A supplied stream exposes a subscription callback and e...
Count Machines and Recover a Distributed Tree Topology
Count Machines and Recover a Distributed Tree Topology A cluster's machines form a rooted tree. Design a protocol that returns the number of machines ...
Design an Extensible In-Memory Logger and Keyword Search
Design an Extensible In-Memory Logger and Keyword Search Design an object-oriented in-memory logger that can store messages and independently support ...
Reason About Rate Limiting Under Memory and Throughput Pressure
Reason About Rate Limiting Under Memory and Throughput Pressure Design an in-memory rate limiter and then extend the design for two production concern...
Extend a Banking Interface with Scheduled Payments and Account Merges
Extend a Banking Interface with Scheduled Payments and Account Merges You maintain an in-memory banking service whose public interface already support...
Evaluate an Agentic Decision System End to End
Evaluate an Agentic Decision System End to End You are replacing a rule-based workflow with an agent that selects tools and recommends operational dec...
Design an In-Memory Transactional Key-Value Store
Design an in-memory key-value database that supports transactional reads and writes. Expose a class with these operations: - begin() starts a transact...
Implement a Stateful Chatter Message Store
Implement a Stateful Chatter Message Store Design a Chatter class that can load multiple ordered batches of messages, save its current messages, retur...
Debug Tokenization and Detokenization
Debug Tokenization and Detokenization The source reports a debugging exercise with buggy tokenization and detokenization functions but does not includ...
Build a Wordle-Style Game in React
Build a Wordle-Style Game in React Build a small Wordle-style game from scratch in React. The secret is a five-letter word, and the player has at most...
Index a CSV Movie Catalog for Fast Year-Range Queries
Index a CSV Movie Catalog for Fast Year-Range Queries Design a class that loads a CSV movie catalog once and then answers frequent year-range filters ...
Design a Durable DAG Workflow for Order Refunds
Design a Durable DAG Workflow for Order Refunds An order that times out may need a refund. You are given a directed acyclic graph of refund steps and ...
Build a Resilient Chain of Clue-Driven HTTP Requests
Build a Resilient Chain of Clue-Driven HTTP Requests Implement or design a client that starts from one URL and follows a chain of HTTP responses. A su...
Build a Crash-Consistent Single-Server Key-Value Store
Build a Crash-Consistent Single-Server Key-Value Store Implement and explain a key-value store that runs in one server process and persists byte-strin...
Explain BIOS and UEFI Firmware Mechanisms
Explain BIOS and UEFI Firmware Mechanisms Answer the following firmware and low-level systems questions. State assumptions about architecture and firm...
Implement a Rolling-Window Rate Limiter
Implement a Rolling-Window Rate Limiter Implement an in-memory rate limiter that accepts at most limit requests in any rolling interval of window_seco...
Design Prefix-Aware Deduplication for Homepage Content Rows
Design Prefix-Aware Deduplication for Homepage Content Rows A homepage contains ordered rows of content IDs. Each row has its own ordered candidate li...
Debug Python LRU Cache-Key Construction
Debug Python LRU Cache-Key Construction The source reports a Python LRU-cache bug in key construction from args and **kwargs but does not provide the ...