•SYSTEM DESIGN
Roblox System Design Questions
Every system design problem candidates reported at Roblox between September 2025 and September 2026, most-asked first. Each one links to a full solution.
Problems
6
Candidate reports
8
Asked more than once
2
start here
Question type
6 HLD
Design Multi-Dimensional Request Rate Limiting
Design a distributed rate limiter that protects APIs by limiting requests (or consumed units such as LLM billing tokens or storage quota) per user, API key, tenant, or IP. It must support configurable rules (e.g., 100…
Also worded as: Design a rate limiter
Design a Scalable Likes System
Design a scalable likes system for posts or games: users like and unlike items, see whether they have liked something, and see like counts. Popular items receive huge bursts of likes (hot keys). Requirements: each user can like…
Also worded as: Design a Scalable Like Counter
Design a Real-Time Shared To-Do List
Design a to-do list service: users create, read, update, delete, complete and reorder tasks in lists. The basic version focuses on REST API design, authentication, rate limiting, caching and API versioning. The real-time variant…
Design a Played-By Summary System
Design a 'played by your friends' social-proof feature for a game platform: on each game page, show a user how many of their friends (and which ones) played that game recently. Discuss maintaining the friend graph, recording play…
Design a Reusable Dropdown Menu Component
Design a reusable, production-grade dropdown (select) menu UI component for a design system. Discuss its public API (props), controlled vs uncontrolled state, keyboard navigation and accessibility (ARIA roles, focus management),…
Design favorites and social game recommendations
Design a recommendation system from scratch, for example recommending posts, games, local sports teams or weekly deals to users. Cover candidate generation (collaborative filtering, content-based, social signals, location),…
Duplicate reports of the same problem are merged and counted.
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What system design questions does Roblox ask?
Candidates reported 6 distinct system design problems at Roblox between September 2025 and September 2026, including Design Multi-Dimensional Request Rate Limiting, Design a Scalable Likes System, Design a Real-Time Shared To-Do List.
How to prepare for Roblox system design interview?
Start with the Roblox problems reported most often, work through each full solution, then practice explaining a design end to end under time pressure in a mock interview.
What is the difference between HLD and LLD at Roblox?
HLD (High-Level Design) focuses on system architecture, scalability, and component interactions. LLD (Low-Level Design) dives into class diagrams, API contracts, and database schemas. Roblox tests both.