Software Engineer Interview Questions
Practice 4,358 real Software Engineer interview questions for 2026 — real questions from actual interviews with detailed solutions to speed your interview preparation. This collection reflects what top tech firms like Meta, Amazon, Google, DoorDash, and TikTok typically evaluate: rigorous coding and algorithmic problem solving, increasing expectations for end-to-end system design (including GenAI/LLM design at some teams), clear complexity analysis, and reliable engineering judgment under constraints. Expect a multi-stage pipeline: recruiter screen, timed or asynchronous coding assessments, one-to-more live coding rounds focused on data structures and correctness, system-design conversations for mid and senior levels, and behavioral/hiring-manager interviews that probe ownership and collaboration. To prepare, prioritize patterned practice (timed mock interviews and implementation + optimization), learn scalable design frameworks, rehearse concise trade-off communication, and tailor examples to company signals like Amazon’s leadership lens or product/latency focus at delivery and media-driven teams. Consistent, feedback-driven practice that combines problem-solving speed, clean code, and measured design reasoning is the quickest path to offers.
"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."
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"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."
Compute unique-substring length and first unique index
Solve the following two string problems. Problem 1 — Longest substring with all distinct characters Given a string s, find the length of the longest c...
Dedupe titles in per-shelf viewport
You are rendering a streaming app home page. - The home page consists of shelves displayed from top to bottom. - Each shelf contains a list of titleId...
Minimize total distance to a store
Question 1: Choose a CVS location to minimize total distance You are given an M x N grid grid containing only 0 and 1. - grid[r][c] = 1 means there is...
Troubleshoot a single-node web outage
You own a single-machine web server (one host running the web service). Suddenly users report that a specific page (or the whole website) is down. 1. ...
Design a CI/CD release notification service
CI/CD Release Notifier (OOD) You are designing an object-oriented component for a service that performs an automated CI/CD release every day. Requirem...
Check if one string is a subsequence of another
Given two strings s and t, determine whether s is a subsequence of t. A subsequence keeps relative order but does not require contiguous characters. I...
Design a distributed key-value store
Scenario Design a distributed key-value (KV) store. Requirements Functional - API: - Get(key) -> value | not_found - Put(key, value) (optionally w...
Implement a thread-safe high-concurrency LRU cache
Problem Design and implement an in-memory LRU (Least Recently Used) cache that supports concurrent access. Basic requirements Implement a cache with f...
Merge K timestamped lists with timestamp coalescing
You are given k sorted lists (or linked lists) of records. Each record has: - timestamp (integer) - values (an array of integers sorted in non-decreas...
Serialize and deserialize a binary tree
Problem Design two functions to serialize and deserialize a binary tree. - Serialize: convert a binary tree into a single string. - Deserialize: recon...
Write SQL for top spender and non-spenders
SQL Questions Assume the following schema: - users(user_id, created_at, ...) - transactions(txn_id, user_id, amount, txn_ts) - amount is a positive ...
Compute minimax grid path and network delay
Problem (two related shortest-path tasks) Part 1 — Minimize the maximum value along a grid path ("minimax" path) You are given an m x n integer grid H...
Explain owning and debugging infra modules
Describe a time you were responsible for a storage/distributed-systems/infra component (or a similarly low-level, reliability-critical module). The in...
Find all dictionary words in a grid
You are given: - A 2D grid of characters board with m rows and n columns. - A list of strings words (a dictionary). A word can be formed by starting f...
Design playlist with add/remove/shuffle
Music Playlist Data Structure Design an in-memory Playlist data structure that supports the following operations on a set of songs: - add(songId): Add...
Evaluate ACL rules for IP and CIDR
Problem You are implementing an IPv4 access-control list (ACL). The ACL contains ordered rules; each rule has: - action: either ALLOW or DENY - cidr: ...
Implement undo/redo with two stacks
Problem: Undo/Redo for a Simple Text Editor Design a data structure that simulates a very small text editor with undo and redo. You are given a sequen...
Design a resource change tracking database
Scenario You are building part of an Azure-like cloud control plane. Resources (VMs, networks, storage accounts, etc.) are stored as JSON documents an...
Explain Kafka architecture and reliability semantics
Explain Kafka architecture and reliability semantics Kafka Architecture and End-to-End Semantics You are asked to explain Kafka's core architecture an...
Solve bank, password, expression algorithm tasks
Solve bank, password, expression algorithm tasks Implement a banking system that supports four specified operations within 90 minutes. Implement a pas...