Real Interview Questions, Not Practice Problems
Curated from real candidate experiences — know exactly what companies are asking right now.
✓Recently asked coding & system design questions✓Company-specific & sorted by date
Plaid
#1
Design a Bank Account Linking System
oauthsecuritybanking-api
High FrequencySystem DesignhardFREE
Stripe
#2
Debug a Payment Processing Pipeline
debuggingpaymentsconcurrency
High FrequencyCodinghardFREE
OpenAI
#3
Design a Model Training Pipeline
ml-trainingdistributed-systemsdata-pipeline
CommonSystem DesignhardFREE
Databricks
#4
Rate Limiter for API Gateway
rate-limitingdistributed-systemsapi-design
High FrequencyLLDmediumFREELC
Stripe
#5
Design a Subscription Billing System
billingpaymentssubscriptions
High FrequencySystem DesignhardFREE
OpenAI
#6
Build a Token Counter and Context Manager
tokenizationcontext-managementllm
High FrequencyCodingmediumFREE
Plaid
#7
Implement a Transaction Categorization Engine
categorizationmachine-learningfinancial-data
High FrequencyCodingmediumFREE
Netflix
#8
Design a Video Recommendation Engine
recommendation-systemsmachine-learningpersonalization
High FrequencySystem DesignhardFREE
Databricks
#9
Design a Distributed Query Engine
distributed-systemsquery-optimizationfault-tolerance
High FrequencySystem DesignhardFREE
Netflix
#10
Design a Real-Time Analytics Dashboard
real-time-analyticsstreamingmonitoring
CommonSystem DesignmediumFREE
Stripe
#11
Implement a Webhook Delivery System
webhooksreliabilityevent-driven
High FrequencyLLDmediumFREE
Anthropic
#12
Design an LLM Serving Infrastructure
llm-servinggpu-managementauto-scaling
CommonSystem DesignhardFREE
OpenAI
#13
Implement a KV Cache for Transformer Inference
kv-cachetransformergpu-memory
CommonCodinghardFREELC
Plaid
#14
Design a Financial Data Aggregation Pipeline
data-aggregationetlrate-limiting
CommonSystem DesignhardFREE
Snowflake
#15
Design a Virtual Warehouse Architecture
virtual-warehouseauto-scalingmulti-tenant
CommonSystem DesignhardFREE
Netflix
#16
Implement an Adaptive Bitrate Streaming Algorithm
streamingadaptive-bitratenetworking
CommonCodinghardFREE
Anthropic
#17
Build a Concurrent Rate-Limited API Client
concurrencyrate-limitingapi-client
High FrequencyCodingmediumFREELC
Coinbase
#18
Design a Cryptocurrency Exchange Order Book
order-bookmatching-enginereal-time
High FrequencySystem DesignhardFREE
Databricks
#19
Streaming Window Aggregations
streamingsliding-windowdata-processing
CommonCodinghardFREELC
Stripe
#20
API Rate Limiting with Usage-Based Billing
rate-limitingbillingapi-design
CommonCodingmediumFREELC
Anthropic
#21
Implement a Token-Level Streaming Parser
streamingparsingllm
CommonCodingmediumFREE
OpenAI
#22
Design an API Gateway for AI Models
api-gatewayload-balancinggpu-management
CommonSystem DesignhardFREE
Snowflake
#23
Implement a Micro-Partition Pruning Algorithm
partition-pruningzone-mapsbloom-filter
CommonCodinghardFREE
Plaid
#24
Build a Webhook Notification System
webhooksreal-timeevent-driven
CommonCodingmediumFREE
Coinbase
#25
Build a Real-Time Price Feed Aggregator
price-feedaggregationreal-time
CommonCodingmediumFREELC
Netflix
#26
Design a CDN Routing System
cdnroutingcaching
CommonSystem DesignhardFREE
Snowflake
#27
Design a Time Travel Feature
time-travelversioningstorage-optimization
CommonSystem DesignhardFREE
Coinbase
#28
Implement a Blockchain Transaction Tracker
blockchaintransaction-monitoringchain-reorg
CommonCodinghardFREE
Figma
#29
Design a Real-Time Collaborative Editor
crdtreal-time-collaborationconflict-resolution
High FrequencySystem DesignhardFREE
Databricks
#30
Delta Table Compaction
data-lakecompactionconcurrency
CommonCodinghardFREELC
Netflix
#31
Build a Chaos Engineering Framework
chaos-engineeringfault-injectionresilience
CommonLLDhardFREE
Stripe
#32
Design a Fraud Detection System
fraud-detectionmachine-learningreal-time
CommonSystem DesignhardFREE
Anthropic
#33
Design a Prompt Evaluation Pipeline
evaluationa-b-testingllm
CommonSystem DesignhardFREE
OpenAI
#34
Design a Plugin/Tool Execution Sandbox
sandboxsecuritytool-execution
CommonSystem DesignhardFREE
Snowflake
#35
Build a Result Cache System
cachingquery-resultsinvalidation
CommonCodingmediumFREELC
Plaid
#36
Design an Identity Verification Service
kycidentity-verificationcompliance
CommonSystem DesignhardFREE
Coinbase
#37
Design a Hot/Cold Wallet System
walletcustodysecurity
CommonSystem DesignhardFREE
Figma
#38
Implement a Canvas Rendering Engine
canvasrendering2d-graphics
CommonCodinghardFREE
Snowflake
#39
Design a Secure Data Sharing Platform
data-sharingaccess-controlmulti-tenant
CommonSystem DesignmediumFREE
Coinbase
#40
Design a KYC/AML Compliance Pipeline
kycamlcompliance
CommonSystem DesignmediumFREE
Figma
#41
Design a Design System Component Library
design-systemscomponent-libraryversioning
CommonLLDmediumFREE
Databricks
#42
Design a Notebook Execution Engine
distributed-systemsexecution-engineresource-management
CommonSystem DesignhardFREE
Anthropic
#43
Design a Conversation Memory System
llmcontext-managementsummarization
System DesignhardFREE
Figma
#44
Build a Vector Graphics Diff Algorithm
diffingvector-graphicsalgorithms
CommonCodinghardFREELC
Figma
#45
Design a Plugin Sandbox Architecture
plugin-systemsandboxsecurity
System DesignhardFREE
Rippling
#46
Task Runner with Concurrency Limit
javascriptasyncconcurrency
CommonCodingmediumFREE
Rippling
#47
Design Masonry Layout (Pinterest-style)
frontend-system-designlayoutperformance
CommonSystem DesignmediumFREE
Rippling
#48
Currency Exchange Arbitrage Detection
graphbellman-fordnegative-cycle
CommonCodingmediumFREELC
Rippling
#49
LFU Cache with LRU Tiebreaker
data-structurescachehash-map
CommonCodinghardFREELC
Rippling
#50
Optimal Game Strategy (Array Ends)
dynamic-programminggame-theoryarrays
CommonCodingmediumFREELC