Scale AI
Easy
Software EngineerDesign a Streaming Job Scheduler
System Design
9
0
April 9, 2026
Scalability Interview Questions
Scalability questions test whether you can design systems that handle growing load without degrading performance.
Expect questions on horizontal vs vertical scaling, database sharding, data partitioning strategies, and capacity planning.
Interviewers look for awareness of bottlenecks, trade-offs between consistency and throughput, and practical experience with scaling patterns.
911Questions
163Companies
Easy 42 • Medium 378 • Hard 479Difficulty mix
Common scalability interview patterns
- Horizontal vs vertical scaling trade-offs
- Database sharding strategies (hash, range, geographic)
- Read replicas and write scaling
- Stateless service design for horizontal scaling
- Auto-scaling policies and capacity planning
- Data partitioning and rebalancing
Scalability interview questions
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HubSpot
Easy
Software EngineerDesign a Netflix-like video platform
System Design
6
0
December 15, 2025
PayPal
Hard
Machine Learning EngineerDesign a traditional fraud detection system
ML System Design
6
0
September 6, 2025
DoorDash
Hard
Software EngineerDesign consistent hashing for sharding
System Design
9
0
September 6, 2025
LinkedIn
Medium
Software EngineerDesign an in-memory key-value store using maps
System Design
11
0
November 21, 2025
DoorDash
Medium
Software EngineerDesign consistent hashing with a sorted map
System Design
9
0
August 7, 2025
OpenAI
Hard
Software EngineerDesign an AI playground editor
System Design
7
0
April 2, 2026
Harvey
Medium
Backend EngineerDesign a secure document vault
System Design
11
0
February 18, 2026
LinkedIn
Medium
Software EngineerDesign a scalable key-value store
System Design
10
0
December 8, 2025
Rippling
Hard
Software EngineerImplement a minimal local HTTP server
System Design
9
0
September 6, 2025
Amazon
Hard
Software EngineerDesign a replicated cloud storage service
System Design
6
0
January 22, 2026
Datadog
Hard
Software EngineerDesign an image detection system
ML System Design
11
0
September 6, 2025
HubSpot
Hard
Software EngineerDesign a Netflix-like streaming platform
System Design
8
0
July 31, 2025
Axon
Medium
Software EngineerDesign an image-to-multilanguage translator
System Design
6
0
February 3, 2026
OpenAI
Hard
Software EngineerDesign a URL shortening service
System Design
10
0
December 8, 2025
Rippling
Hard
Software EngineerDesign a Google News-like aggregator
System Design
10
0
September 6, 2025
Axon
Medium
Software EngineerDesign analytical tracking database
System Design
10
0
August 4, 2025
Roblox
Hard
Software EngineerDesign game matchmaking and waiting queue
System Design
11
0
July 15, 2025
Bloomberg
Hard
Software EngineerDesign streaming mention analytics with search and alerts
System Design
9
0
March 1, 2026
OpenAI
Medium
Software EngineerDesign Slack-like multi-tenant global messaging system
System Design
10
0
December 1, 2025
Common mistakes in scalability discussions
- Jumping to scaling solutions before estimating actual load
- Ignoring the consistency implications of horizontal scaling
- Overlooking hot partition problems in sharding schemes
- Not considering the operational complexity of distributed systems
- Assuming vertical scaling is always simpler
How scalability questions are evaluated
Structured reasoning about load estimation and bottleneck identification matters most.
Show awareness of trade-offs rather than presenting a single solution.
Discuss failure modes and how the system degrades under extreme load.