@ -1,37 +1,8 @@
@@ -1,37 +1,8 @@
[
{
"id" : "url-shortener-easy" ,
"name" : "URL Shortener" ,
"description" : "Build a basic service to shorten URLs with a single backend." ,
"difficulty" : "easy" ,
"targetRps" : 100 ,
"durationSec" : 60 ,
"maxMonthlyUsd" : 100 ,
"maxP95LatencyMs" : 200 ,
"requiredAvailabilityPct" : 99.0 ,
"mustInclude" : [ "database" ] ,
"hints" : [ "Start with a basic backend and persistent storage." ] ,
"interviewerRequirements" : [
"Users should be able to shorten a URL via a basic web interface or API." ,
"Each shortened URL should redirect to the original URL." ,
"Data should be persisted so links remain valid after a restart."
] ,
"functionalRequirements" : [
"Must include a database to persist mappings"
] ,
"nonFunctionalRequirements" : [
"Target RPS: 100" ,
"Max P95 latency: 200ms" ,
"Required availability: 99.0%" ,
"Max monthly cost: $100" ,
"Simulation duration: 60 seconds"
]
} ,
{
"id" : "url-shortener-medium" ,
"id" : "url-shortener" ,
"name" : "URL Shortener" ,
"description" : "Scale your URL shortener to handle traffic spikes and ensure high availability." ,
"difficulty" : "medium" ,
"targetRps" : 1000 ,
"durationSec" : 180 ,
"maxMonthlyUsd" : 300 ,
@ -58,70 +29,9 @@
@@ -58,70 +29,9 @@
]
} ,
{
"id" : "url-shortener-hard" ,
"name" : "URL Shortener" ,
"description" : "Design a globally distributed URL shortening service with low latency and high availability." ,
"difficulty" : "hard" ,
"targetRps" : 10000 ,
"durationSec" : 300 ,
"maxMonthlyUsd" : 1000 ,
"maxP95LatencyMs" : 100 ,
"requiredAvailabilityPct" : 99.99 ,
"mustInclude" : [ "cdn" , "database" ] ,
"encouragedComponents" : [ "cache" , "messageQueue" ] ,
"hints" : [ "Think about write-path consistency and global replication." ] ,
"interviewerRequirements" : [
"The service must support globally distributed traffic with low latency." ,
"Users across the world should get fast redirects via local CDN edge nodes." ,
"Writes (shorten requests) should be consistent and durable."
] ,
"functionalRequirements" : [
"Must include a CDN and a database" ,
"Encouraged to include a cache and a message queue" ,
"Writes should pass through a queue before hitting storage (eventual consistency)"
] ,
"nonFunctionalRequirements" : [
"Target RPS: 10000" ,
"Max P95 latency: 100ms" ,
"Required availability: 99.99%" ,
"Max monthly cost: $1000" ,
"Simulation duration: 300 seconds"
]
} ,
{
"id" : "chat-app-easy" ,
"name" : "Chat App" ,
"description" : "Implement a simple chat app for small group communication." ,
"difficulty" : "easy" ,
"targetRps" : 50 ,
"durationSec" : 120 ,
"maxMonthlyUsd" : 150 ,
"maxP95LatencyMs" : 300 ,
"requiredAvailabilityPct" : 99.0 ,
"mustInclude" : [ "webserver" , "database" ] ,
"hints" : [ "You don’t need to persist every message yet." ] ,
"interviewerRequirements" : [
"Users should be able to send and receive messages in real-time." ,
"Messages should be stored to support reloading the page without data loss." ,
"A basic frontend should connect to a backend service."
] ,
"functionalRequirements" : [
"Must include a webserver and a database"
] ,
"nonFunctionalRequirements" : [
"Target RPS: 50" ,
"Max P95 latency: 300ms" ,
"Required availability: 99.0%" ,
"Max monthly cost: $150" ,
"Simulation duration: 120 seconds"
]
} ,
{
"id" : "chat-app-medium" ,
"id" : "chat-app" ,
"name" : "Chat App" ,
"description" : "Support real-time chat across mobile and web, with message persistence." ,
"difficulty" : "medium" ,
"targetRps" : 500 ,
"durationSec" : 300 ,
"maxMonthlyUsd" : 500 ,
@ -148,70 +58,9 @@
@@ -148,70 +58,9 @@
]
} ,
{
"id" : "chat-app-hard" ,
"name" : "Chat App" ,
"description" : "Design a Slack-scale chat platform supporting typing indicators, read receipts, and delivery guarantees." ,
"difficulty" : "hard" ,
"targetRps" : 5000 ,
"durationSec" : 600 ,
"maxMonthlyUsd" : 1500 ,
"maxP95LatencyMs" : 100 ,
"requiredAvailabilityPct" : 99.99 ,
"mustInclude" : [ "messageQueue" , "database" ] ,
"discouragedComponents" : [ "single-instance webserver" ] ,
"hints" : [ "Think about pub/sub, retries, and ordering guarantees." ] ,
"interviewerRequirements" : [
"Messages must support delivery guarantees and deduplication." ,
"Users must receive typing indicators and read receipts in near-real-time." ,
"System must scale horizontally and tolerate node failures."
] ,
"functionalRequirements" : [
"Must include a message queue and database" ,
"Discouraged from using a single-instance webserver" ,
"Encouraged to use a publish/subscribe system for fan-out"
] ,
"nonFunctionalRequirements" : [
"Target RPS: 5000" ,
"Max P95 latency: 100ms" ,
"Required availability: 99.99%" ,
"Max monthly cost: $1500" ,
"Simulation duration: 600 seconds"
]
} ,
{
"id" : "netflix-easy" ,
"name" : "Netflix Clone" ,
"description" : "Build a basic video streaming service with direct file access." ,
"difficulty" : "easy" ,
"targetRps" : 200 ,
"durationSec" : 300 ,
"maxMonthlyUsd" : 500 ,
"maxP95LatencyMs" : 500 ,
"requiredAvailabilityPct" : 99.0 ,
"mustInclude" : [ "cdn" ] ,
"hints" : [ "You don’t need full-blown adaptive streaming yet." ] ,
"interviewerRequirements" : [
"Users should be able to request and stream a video file." ,
"Content should be served via a CDN to reduce latency and bandwidth cost." ,
"Playback does not require adaptive streaming."
] ,
"functionalRequirements" : [
"Must include a CDN to serve static video content"
] ,
"nonFunctionalRequirements" : [
"Target RPS: 200" ,
"Max P95 latency: 500ms" ,
"Required availability: 99.0%" ,
"Max monthly cost: $500" ,
"Simulation duration: 300 seconds"
]
} ,
{
"id" : "netflix-medium" ,
"id" : "netflix-clone" ,
"name" : "Netflix Clone" ,
"description" : "Add video transcoding, caching, and recommendations." ,
"difficulty" : "medium" ,
"targetRps" : 1000 ,
"durationSec" : 600 ,
"maxMonthlyUsd" : 2000 ,
@ -238,70 +87,9 @@
@@ -238,70 +87,9 @@
]
} ,
{
"id" : "netflix-hard" ,
"name" : "Netflix Clone" ,
"description" : "Design a globally resilient, multi-region Netflix-scale system with intelligent failover and real-time telemetry." ,
"difficulty" : "hard" ,
"targetRps" : 10000 ,
"durationSec" : 900 ,
"maxMonthlyUsd" : 10000 ,
"maxP95LatencyMs" : 200 ,
"requiredAvailabilityPct" : 99.999 ,
"mustInclude" : [ "cdn" , "data pipeline" , "monitoring/alerting" ] ,
"encouragedComponents" : [ "messageQueue" , "cache" , "third party service" ] ,
"hints" : [ "You’ll need intelligent routing and fallback mechanisms." ] ,
"interviewerRequirements" : [
"Users worldwide should stream with minimal latency through regional CDN edge nodes." ,
"The system must support failover between regions." ,
"Real-time metrics and alerting must be integrated for proactive issue detection."
] ,
"functionalRequirements" : [
"Must include a CDN, data pipeline, and monitoring/alerting" ,
"Encouraged to use cache and queue for async video processing" ,
"Encouraged to simulate third-party service integrations (e.g. payment, licensing)"
] ,
"nonFunctionalRequirements" : [
"Target RPS: 10000" ,
"Max P95 latency: 200ms" ,
"Required availability: 99.999%" ,
"Max monthly cost: $10000" ,
"Simulation duration: 900 seconds"
]
} ,
{
"id" : "rate-limiter-easy" ,
"name" : "Rate Limiter" ,
"description" : "Build a basic in-memory rate limiter for a single instance service." ,
"difficulty" : "easy" ,
"targetRps" : 200 ,
"durationSec" : 60 ,
"maxMonthlyUsd" : 50 ,
"maxP95LatencyMs" : 100 ,
"requiredAvailabilityPct" : 99.0 ,
"mustInclude" : [ "webserver" ] ,
"hints" : [ "Use an in-memory store and sliding window or token bucket." ] ,
"interviewerRequirements" : [
"Each client should be limited to N requests per minute." ,
"Rate limits should be enforced in memory." ,
"Only one instance is required—no cross-node coordination."
] ,
"functionalRequirements" : [
"Must include a webserver that can reject requests over the configured RPS" ,
"Rate limiting must be enforced locally (no coordination with other nodes)"
] ,
"nonFunctionalRequirements" : [
"Target RPS: 200" ,
"Max P95 latency: 100ms" ,
"Required availability: 99.0%" ,
"Max monthly cost: $50" ,
"Simulation duration: 60 seconds"
]
} ,
{
"id" : "rate-limiter-medium" ,
"id" : "rate-limiter" ,
"name" : "Rate Limiter" ,
"description" : "Design a rate limiter that works across multiple instances and enforces global quotas." ,
"difficulty" : "medium" ,
"targetRps" : 1000 ,
"durationSec" : 180 ,
"maxMonthlyUsd" : 300 ,
@ -329,70 +117,9 @@
@@ -329,70 +117,9 @@
]
} ,
{
"id" : "rate-limiter-hard" ,
"name" : "Rate Limiter" ,
"description" : "Build a globally distributed rate limiter with per-user and per-region policies." ,
"difficulty" : "hard" ,
"targetRps" : 5000 ,
"durationSec" : 300 ,
"maxMonthlyUsd" : 1000 ,
"maxP95LatencyMs" : 30 ,
"requiredAvailabilityPct" : 99.99 ,
"mustInclude" : [ "cache" ] ,
"encouragedComponents" : [ "cdn" , "data pipeline" , "monitoring/alerting" ] ,
"hints" : [ "Ensure low latency despite distributed state. Avoid single points of failure." ] ,
"interviewerRequirements" : [
"Each user must be rate-limited independently and consistently across regions." ,
"The system should avoid global bottlenecks while maintaining quota correctness." ,
"Should include real-time metrics and alerting on quota violations or system degradation."
] ,
"functionalRequirements" : [
"Must include a cache that replicates or partitions rate-limit state regionally" ,
"Rate limiting should be enforced with user-scoped and region-scoped policies" ,
"Must simulate availability zones with failover and latency variance"
] ,
"nonFunctionalRequirements" : [
"Target RPS: 5000" ,
"Max P95 latency: 30ms" ,
"Required availability: 99.99%" ,
"Max monthly cost: $1000" ,
"Simulation duration: 300 seconds"
]
} ,
{
"id" : "metrics-system-easy" ,
"name" : "Metrics System" ,
"description" : "Create a basic system that collects and stores custom app metrics locally." ,
"difficulty" : "easy" ,
"targetRps" : 100 ,
"durationSec" : 120 ,
"maxMonthlyUsd" : 100 ,
"maxP95LatencyMs" : 200 ,
"requiredAvailabilityPct" : 99.0 ,
"mustInclude" : [ "webserver" , "database" ] ,
"hints" : [ "Start by storing metrics as timestamped values in a simple DB." ] ,
"interviewerRequirements" : [
"Metrics should be received via HTTP and stored locally." ,
"No external systems needed—simple write and read support." ,
"Support querying metrics over a time range."
] ,
"functionalRequirements" : [
"Must include a webserver to receive metric data" ,
"Must include a database to persist metrics with timestamps"
] ,
"nonFunctionalRequirements" : [
"Target RPS: 100" ,
"Max P95 latency: 200ms" ,
"Required availability: 99.0%" ,
"Max monthly cost: $100" ,
"Simulation duration: 120 seconds"
]
} ,
{
"id" : "metrics-system-medium" ,
"id" : "metrics-system" ,
"name" : "Metrics System" ,
"description" : "Design a pull-based metrics system like Prometheus that scrapes multiple services." ,
"difficulty" : "medium" ,
"targetRps" : 1000 ,
"durationSec" : 300 ,
"maxMonthlyUsd" : 500 ,
@ -418,36 +145,5 @@
@@ -418,36 +145,5 @@
"Max monthly cost: $500" ,
"Simulation duration: 300 seconds"
]
} ,
{
"id" : "metrics-system-hard" ,
"name" : "Metrics System" ,
"description" : "Build a scalable, multi-tenant metrics platform with real-time alerts and dashboard support." ,
"difficulty" : "hard" ,
"targetRps" : 5000 ,
"durationSec" : 600 ,
"maxMonthlyUsd" : 1500 ,
"maxP95LatencyMs" : 50 ,
"requiredAvailabilityPct" : 99.99 ,
"mustInclude" : [ "monitoring/alerting" , "data pipeline" ] ,
"encouragedComponents" : [ "messageQueue" , "cache" , "third party service" ] ,
"hints" : [ "Think about downsampling, alert thresholds, and dashboard queries." ] ,
"interviewerRequirements" : [
"Support multi-tenant metrics isolation and quota enforcement." ,
"Enable real-time alerting with low-latency threshold evaluation." ,
"Expose APIs for dashboards and custom queries."
] ,
"functionalRequirements" : [
"Must include a data pipeline that can scale with RPS and tenants" ,
"Must include monitoring/alerting logic for low-latency threshold detection" ,
"Encouraged to buffer high-volume ingestion via message queues"
] ,
"nonFunctionalRequirements" : [
"Target RPS: 5000" ,
"Max P95 latency: 50ms" ,
"Required availability: 99.99%" ,
"Max monthly cost: $1500" ,
"Simulation duration: 600 seconds"
]
}
]
