Frontend Engineer Interview Questions
Practice 28 real Frontend Engineer interview questions for 2026 — real interview questions from actual interviews with detailed solutions. This collection targets Frontend Engineer interview questions and practical interview preparation across companies currently hiring heavily for frontend talent, including Toma, Uber, Coinbase, and Robinhood. Expect live React/TypeScript coding, component-level problems, and end-to-end tasks that prove you can ship resilient UI under constraints. What makes frontend loops distinctive is their emphasis on product-quality engineering: component design and state management, DOM and asynchronous behavior, and performance/accessibility under load. At Uber interviews you’ll see DOM-manipulation and async-pattern scenarios and large-scale UI performance tradeoffs; Coinbase favors pixel-perfect implementations, robust form/state synchronization, and edge-case handling; Robinhood tests real-time UI consistency and performance at scale; Toma and other early-stage teams focus on rapid prototyping and full-stack integration. Prep by building expressive, testable components, mastering React patterns and TypeScript typings, profiling and accessibility checks, and rehearsing clear trade-off explanations for design decisions.
"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."
Executive-Round Behavioral: Proactive Decision-Making in Career and Projects
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Design a Reusable Dropdown Menu Component
Design a Reusable Dropdown Menu Component You are building a UI component library used across a large web application. Design a reusable dropdown menu...
Build a React Parking Lot Manager
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Design a ChatGPT Playground
Design a web-based AI playground — a prompt-testing console similar to the OpenAI / ChatGPT Playground. A signed-in user types a prompt, picks a model...
Build a React naval board
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Review Code for Memory Risks
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Design High-Throughput Messaging Infrastructure
Design the backend infrastructure for a service that ingests a high volume of events, durably stores them for later querying, and processes each event...
Design a Scalable Calendar Service
Design an online calendar service (think Google Calendar) that supports both individual and shared calendars. Users must be able to create, update, de...
Build a Streaming Chat Input
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Identify the CSS color function
In CSS, which color function accepts red, green, and blue channel values and can also include an optional opacity value?
Design a Photo Album App
Design a web-based photo album application for the browser (a frontend-focused system design). The product has three main screens, each provided to yo...
Which CSS function supports opacity?
In CSS, which color function accepts red, green, and blue channel values and also allows an optional alpha value to control opacity?
Deduplicate an Array in Linear Time
Given an array of primitive values such as numbers or strings, implement a function that returns a new array with duplicates removed while preserving ...
Simulate a Rank-Based Tournament
You are given an array ranks, where ranks[i] is the rank of player i in the initial bracket order. A smaller rank value means a stronger player. The t...
Build a Weekly Calendar
Implement an interactive weekly calendar UI. Requirements: - Display a one-week calendar with 7 days. - The calendar should be divided into 1-hour tim...
Build a Stateful Calculator
Implement a calculator UI component. Requirements: - Support digit input and the operators +, -, *, and /. - Support = to finalize the current calcula...
Implement a Constant-Time Random Pool
Design a data structure RandomPool that stores unique integers and supports the following operations in average O(1) time: add(value), which inserts v...
Approximate Pi from Random Points
You are given an array pts of points sampled uniformly at random from the unit square [0, 1] x [0, 1]. Each point is represented as an array [x, y], w...
Explain React classes, lifecycle, and hooks
In a frontend interview, explain several core React concepts: 1. Compare class components and function components in terms of syntax, state management...
Build a Web Calculator That Matches a Reference App
You are in a 45–60 minute phone screen (with screen sharing) for a Fullstack/Frontend role. The interviewer shares a link to a simple calculator web a...