OpenAI frontend engineer interviews emphasise JavaScript, DOM manipulation, CSS, accessibility, browser APIs, and UI component architecture.
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coding
Hard
Verified Question
#1
1. Count Machines In A Tree
Category: Tree coding problemYou are given a tree-structured network of machines where each node represents a machine. Machines can only communicate with their parent and...Input: String
Output: Computed result
coding
Medium
Verified Question
#2
2. Implement cd Command
Category: Algorithm coding problemImplement a simplified version of the Unix
cd command. Given a current directory path and a relative destination path, return the final absolute...Input: Given inputOutput: Computed result
coding
Medium
Verified Question
#3
3. Largest Subgrid
Category: Grid/matrix coding problemYou are given a 2D grid of non-negative integers and a maximum sum constraint. Find the largest size of a square sub-grid such that all...Input: 2D grid
Output: Integer
coding
Hard
Verified Question
#4
4. Memory Allocator
Category: Linked list coding problem
Memory Allocator Design a memory allocator that manages a contiguous block of memory. Implement malloc and free operations with efficient...
Output: Computed result
coding
Hard
Verified Question
#5
5. Toy Language Type Inference
Category: String coding problemImplement a type system for a toy programming language that supports primitives, tuples, and generics. Your task is to represent types and infer...Input: List
Output: Computed result
coding
Medium
Verified Question
#6
6. Virus Spread
Category: Grid/matrix coding problemSimulate the spread of a virus through a grid. Each cell can be in one of three states: healthy, infected, or immune. *This is similar to a leetcode...Input: 2D grid
Output: Integer
coding
Medium
Verified Question
#7
7. Bot-Enabled Messaging System
Category: String coding problemYou are building a chat system that supports human users and automated bots. Messages are added to a channel log and may trigger bot responses. The...Input: List
Output: Computed result
coding
Hard
Verified Question
#8
8. Connection Tracker
Category: Algorithm coding problemDesign a social network system that tracks follow relationships between users and preserves a full history through snapshots. The system allows...Input: List
Output: Computed result
coding
Medium
Verified Question
#9
9. GPU Credit Ledger
Category: String coding problemYou are designing a system to manage GPU credits. Each credit grant is valid during a specific time window. Events may arrive out of chronological...Input: String
Output: Computed result
coding
Medium
Verified Question
#10
10. GPU Credit Manager
Category: String coding problemYou are designing a system to manage GPU credits. Each credit grant is valid during a specific time window. Events may arrive out of chronological...Input: String
Output: Computed result
coding
Hard
Verified Question
#11
11. In-Memory SQL Engine
Category: String coding problemDesign an in-memory SQL database that supports creating tables, inserting rows with automatic type inference, and querying with filtering and sorting.Input: List
Output: Computed result
coding
Hard
Verified Question
#12
12. Persistent Key-Value Store
Category: Trie-based coding problemYou are designing a persistent key-value store that serializes its state to a binary storage medium. Native serialization (e.g., JSON, pickle,...Input: Array
Output: Computed result
coding
Hard
Verified Question
#13
13. Shard Rebalancer
Category: String coding problemYou are implementing a shard management system for a distributed key-value store. Each shard is identified by a string and covers a contiguous range...Input: String
Output: Computed result
coding
Hard
Verified Question
#14
14. IP Address Iterator
Category: String coding problemEvery device on the public internet is identified by an IPv4 address written in dotted-decimal notation as
"A.B.C.D", where each octet is an...Input: StringOutput: Computed result
coding
Medium
Verified Question
#15
15. Version Support Finder
Category: Binary search coding problemA software company maintains a sorted list of version strings in ascending chronological order. A critical feature was introduced in one version, and...Input: List
Output: Computed result
coding
Medium
Verified Question
#16
16. Monster Battle Simulator
Category: String coding problemSimulate a deterministic, turn-based battle between two ordered teams of monsters. Execute the fight step by step and produce a chronological battle...Input: List
Output: Computed result
coding
Medium
Verified Question
#17
17. Distributed Tree Messaging
Category: Tree coding problemYou are implementing a message-passing protocol for a distributed system organized as a rooted n-ary tree. Each node represents a machine and...Input: List
Output: Printed output
system design
Hard
Verified Question
#18
18. Top 5 Open AI System Design Questions
Category: Trie-based system design problem
System Design Questions - OpenAI A collection of commonly asked system design questions from OpenAI interviews.
Input: Given inputOutput: Computed result
coding
Medium
sliding window
#1
1. [OA] Sliding Window Technique — Manage a live stream of chatbot messages
OpenAI's chatbot service needs to display a limited number of recent messages without overwhelming users. This exercise involves implementing a sliding window algorithm to fetch and manage the latest messages.
Given an array of
Function Signature:
Example 1:
Input:
Output:
Explanation: The function returns the last two messages sent to the chatbot.Constraints:
Given an array of
messages and a number k, write a function that returns the last k messages sent to the chatbot.Function Signature:
function getLatestMessages(messages: string[], k: number): string[]Example 1:
Input:
getLatestMessages(["Hello", "How can I assist you?", "What is OpenAI?", "I love AI!"], 2)Output:
['What is OpenAI?', 'I love AI!']Explanation: The function returns the last two messages sent to the chatbot.Constraints:
- The
messagesarray will have at least one message and at most10^4messages. kwill be a positive integer not exceeding the number of messages.
coding
Hard
async programming
#2
2. [OA] Event Loop — Implement a custom Promise for OpenAI's asynchronous data fetching
In a rapidly evolving tech landscape, OpenAI needs robust data fetching capabilities to enhance user experience. This problem requires implementing a custom
Implement a custom
Input: new Promise((resolve, reject) => { resolve('Success'); })
Output: 'Success'
Explanation: The promise resolves successfully with the value 'Success'.Constraints:
Promise that includes unique features tailored to OpenAI's needs.Implement a custom
Promise class complying with the following methods:resolve(value: any): void— resolve the promise with the givenvalue.reject(reason: any): void— reject the promise with the givenreason.then(onResolved: Function, onRejected: Function): Promise— register callbacks to receive either a resolved value or a rejection reason, and return a new promise resolving to the return value of the called callback.
Input: new Promise((resolve, reject) => { resolve('Success'); })
Output: 'Success'
Explanation: The promise resolves successfully with the value 'Success'.Constraints:
- Input values are any valid JavaScript data types.
- The promise must maintain a proper chain for chaining multiple
thencalls.
system design
Senior
messaging
#3
3. [OA] Design a Notification System for real-time updates
In developing OpenAI's products such as ChatGPT, a notification system for real-time updates on chat or model responses is essential. Design a system that allows publishing notifications and subscribing clients to receive them.
Define a class
Input:
Output:
Explanation: Clients registered to receive notifications get the latest updates when
Define a class
NotificationSystem that manages subscribers and notifications. Implement the following methods:subscribe(clientId: string, callback: Function): void— register a client with a callback to be notified.unsubscribe(clientId: string): void— remove a client from the list of subscribers.notify(message: string): void— send a message to all registered clients.
Input:
const notificationSystem = new NotificationSystem();notificationSystem.subscribe('client1', (msg) => console.log(msg));notificationSystem.notify('New message received!');Output:
New message received!Explanation: Clients registered to receive notifications get the latest updates when
notify is called.Constraints:- Client IDs are unique strings.
- Each notification should reach all active subscribers.
system design
Senior
api design
#4
4. [OA] Design a Client-Side Router for a Single Page Application
OpenAI's applications such as Codex require efficient navigation without reloading entire pages. You are tasked with designing a client-side router for a web application.
Define a class
Input:
Output:
Explanation: Navigating to '/home' invokes the respective callback.Constraints:
Define a class
Router that manages routes in an SPA. You should implement the following methods:addRoute(path: string, callback: Function): void— register a route with a specific path and callback function.navigate(path: string): void— navigate to the specified path and call the associated route's callback.getCurrentPath(): string— return the current path of the application.
Input:
const router = new Router(); router.addRoute('/home', () => console.log('Home Page')); router.navigate('/home');Output:
Home PageExplanation: Navigating to '/home' invokes the respective callback.Constraints:
- Path strings will always start with '/' and only contain alphanumeric characters and slashes.
- A route can only be registered once.
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