Rippling
Hard
Software EngineerDesign a user behavior tracking system
System Design
34
0
February 11, 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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Netflix
Medium
Software EngineerDesign ad frequency capping
System Design
27
0
April 15, 2026
Databricks
Hard
Software EngineerDesign a KV store with QPS API
System Design
13
0
February 4, 2026
Instacart
Hard
Software EngineerDesign product catalog service
System Design
29
0
August 4, 2025
Harvey AI
Hard
Software EngineerDesign a production file storage service
System Design
21
0
September 6, 2025
Roblox
Hard
Software EngineerDesign sliding-window rate limiter with multi-keys
System Design
24
0
July 16, 2025
Databricks
Medium
Software EngineerDesign a stock order manager
System Design
24
0
April 12, 2026
Netflix
Hard
Software EngineerModel data for an ads platform
System Design
23
0
January 20, 2026
DoorDash
Medium
Software EngineerDesign a donations service with 3-day rolling totals
System Design
19
0
December 16, 2025
Coinbase
Hard
Software EngineerDesign a bank account ledger
System Design
24
0
September 6, 2025
Rippling
Hard
Software EngineerDesign a hotel search and booking system
System Design
19
0
December 8, 2025
Jane Street
Easy
Software EngineerValidate order book data across multiple databases
System Design
17
0
December 15, 2025
Databricks
Hard
Software EngineerDesign a thread-safe bounded queue
System Design
16
0
September 6, 2025
Axon
Medium
Software EngineerDesign fulfillment truck routing and inventory system
System Design
18
0
March 1, 2026
Airbnb
Medium
Software EngineerDesign a booking system
System Design
20
0
February 12, 2026
DoorDash
Medium
Software EngineerDebug round-robin request router
System Design
17
0
August 9, 2025
Parafin
Hard
Software EngineerDesign loan application system
System Design
31
0
August 4, 2025
Meta
Hard
Data EngineerDesign batch and streaming ETL architecture
System Design
25
0
July 15, 2025
Anthropic
Hard
Software EngineerEstimate VRAM and compare model parallelism
ML System Design
23
0
November 19, 2025
OpenAI
Hard
Software EngineerDesign an online ads serving system
System Design
23
0
September 6, 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.