Backend Engineer Interview Questions
Practice 69 real Backend Engineer interview questions for 2026 — Backend Engineer interview questions drawn from actual interviews with detailed solutions to accelerate your interview preparation. This collection focuses on the problems and decision points hiring teams actually ask: correctness and complexity in coding, API and data-model design, consistency and failure modes, performance and scaling tradeoffs, and clear behavioral stories that show ownership and impact. Expect questions that probe system thinking as much as language fluency and debugging. Companies actively hiring for backend engineers right now include Bytedance, Tesla, Harvey, and Roku, and their interview themes overlap but differ in emphasis. Bytedance and Harvey emphasize high-throughput APIs, streaming/real-time pipelines, and model-inference integration; Tesla stresses diagnostics, observability, and reliability for distributed vehicle or factory services; Roku focuses on content ingestion, metadata pipelines, and low-latency playback backends. To prepare, practice coding with complexity limits, sketch production-ready APIs and data models, review failure/recovery patterns, and rehearse concise STAR behavioral stories tied to measurable outcomes.
"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."
Implement ad filtering and concurrent cache
This question evaluates algorithmic problem-solving and systems-programming skills by combining an ad candidate filtering task that tests data-structu...
Implement tag matcher and filesystem
This interview reportedly included two coding problems: 1. Tag matching in text Given a sentence and a list of tags or keywords, return the tags th...
Replace Dashes With Nearest Letters
This question evaluates a candidate's competence in grid traversal, distance computation using Manhattan metrics, and handling tie-breaking rules incl...
Solve coding and AI-assisted tasks
This set evaluates algorithmic problem-solving across arrays, immutable linked-list interfaces, parent-pointer tree traversal, string validity via min...
Find First Anagram Occurrence
Given two strings text and pattern, return the starting index of the first substring in text that is an anagram of pattern. If no such substring exist...
Implement Notification Rate Limiter
Implement should_send_notifications(user_id, timestamp) -> bool. You are given two mappings: - each user_id belongs to exactly one team_id - each team...
Count Cross-Group Employee Pairs
You are given n employees labeled from 0 to n - 1 and a list of relationships relations, where each pair [a, b] means employees a and b belong to the ...
Compute time to burn tree
Given the root of a binary tree and the value of a target node that starts burning at time 0, fire spreads every minute from a burning node to its lef...
Implement BFS and a Job Scheduler
The interview report described two coding questions: grid reveal with BFS and a concurrent periodic job scheduler. Constraints & Assumptions - For the...