Design a Real-Time Shared To-Do List
Last updated: August 31, 2026
Quick Overview
The question asks you to design a real-time shared to-do list application, focusing on the architecture and components necessary to support real-time updates and collaboration among users.
Roblox
August 31, 20262
0
19 solved
The question asks you to design a real-time shared to-do list application, focusing on the architecture and components necessary to support real-time updates and collaboration among users.
This question is typically asked in the technical screen round to assess a candidate's ability to design scalable and efficient systems. The interviewer evaluates the candidate's understanding of real-time data synchronization, user interactions, and the overall architecture of the system. This question also tests the candidate's ability to think critically about trade-offs and system constraints.
What the Interviewer Expects
- Identify core functionalities of a shared to-do list application.
- Outline a high-level architecture including components like databases and real-time communication.
- Discuss data consistency and synchronization methods.
- Consider scalability and performance implications.
- Address potential challenges and trade-offs in the design.
Key Topics to Cover
How to Approach This
- Start by clarifying functional and non-functional requirements with the interviewer.
- Estimate the scale: QPS, storage, bandwidth. This drives your design decisions.
- Draw a high-level architecture first, then deep dive into 1-2 critical components.
- Discuss trade-offs explicitly (e.g., consistency vs availability, SQL vs NoSQL).
- Address failure scenarios, monitoring, and how the system handles 10x traffic spikes.
Possible Follow-up Questions
- How would you handle conflicts when multiple users edit the same task?
- What database would you choose for this application and why?
- Can you explain how you would ensure data consistency across different devices?
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Practice System Design ProblemsSample Answer
Requirements
To design a real-time shared to-do list, we need to identify key requirements: 1. Users should be able to create, read, update, and delete tasks. 2. Changes made by one user should be instantly reflec...
High-Level Design
The architecture could consist of the following components: - Frontend: A web or mobile interface where users can interact with the to-do list. - Backend: A RESTful API to handle requests and ...
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