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."
Describe leadership, AI perspective, and challenges
In a prerecorded video interview for an implementation-related engineering intern role, you may be asked several behavioral questions: 1. Describe a t...
Explain reliability and runtime fundamentals
You may be asked several short technical-fundamentals questions such as: - In a Kafka-based batch consumer, how would you prevent a batch from being p...
Describe conflict and proudest work
You may be asked behavioral questions such as: - Tell me about a time you had a conflict with a teammate or partner team. What happened, how did you h...
Design a Ride-Hailing Platform
This question evaluates competency in designing large-scale, real-time distributed systems, including distributed architecture, geo-spatial indexing a...
Determine If One Binary Tree Is a Substructure of Another
This question evaluates practical tree traversal skills and the ability to implement structural matching between two binary trees. It tests recursive ...
SQL: Students Above Average and Passing Every Subject
This question tests practical SQL skills, specifically the use of aggregate functions and conditional filtering across grouped data. It evaluates the ...
Design an Elevator Control System
Design an object-oriented elevator control system for a building with multiple floors and multiple elevators. The system should support: - Hall reques...
Design booking and settlement systems
You may be asked one or more backend-heavy system design problems such as: 1. Design a reserved-seat ticketing platform similar to a concert or sports...
Count and Rank Words in a Paragraph
Count case-insensitive ASCII words in a paragraph and return deterministic frequency rankings. Tokenize maximal letter runs, normalize to lowercase, s...
Explain timing and testability concepts
For a digital implementation or backend-focused interview, explain the following concepts: 1. What are setup time and hold time? 2. How does clock ske...
Solve Bracket Matching and Tree Width
This composite question evaluates proficiency with core data structures and algorithmic reasoning, covering string-based bracket validation (sequence ...
Reorder Search Results for Provider Diversity
Build a function that paginates ordered provider listings for a telehealth marketplace. Each input record is a CSV string in the format: provider_id, ...
Design Webhooks and Metric Aggregation
The interview report described two system design rounds: a webhook delivery platform and a vehicle metrics aggregation system. Constraints & Assumptio...
Implement Popular and Ranked Voting
You are given ranked ballots in aggregated form. Each key is an ordered tuple of candidate names representing one voter's preference from highest to l...
Design a Chat Analytics Backend
Design the backend of an internal analytics system for a conversational AI product similar to ChatGPT. The goal is to power an analytical metrics dash...
Distribute Annual Revenue Across Twelve Months
Distribute Annual Revenue Across Twelve Months Implement distribute_revenue(annual_cents). The input is a non-negative integer amount of annual revenu...
Design a Therapy Matching Marketplace
Design the backend for a marketplace that matches patients with therapists. The platform should support: - Patients searching for therapists by specia...
Convert IPv4 Ranges to CIDR Blocks
Implement a function that summarizes a consecutive IPv4 address range using the smallest possible list of CIDR blocks. You are given: - start_ip: a va...
Compare Strings With Deletions
You are given two strings s and t. Each string may contain lowercase letters and the special character #. A # deletes the closest non-deleted characte...
Solve classic backend coding problems
This multi-part question evaluates algorithmic problem solving and implementation skills, including string parsing and segmentation, combinatorial rea...