EngPrep — Real Engineering. Real Interviews.

←

SYSTEM DESIGNDesign Google Maps (Routing)GoogleAppleHERE

TRAFFIC LEVEL

—/3

CONSTRAINTS

Route requests/day100M

Map nodes (US)100M intersections

Map edges200M road segments

Traffic update cadenceEvery 5 min

Navigation sessions10M concurrent

Compute & Network

Load BalancerDistribute traffic

API GatewayEntry point / auth

API ServerBusiness logic

Worker NodeAsync processing

CDN EdgeGlobal cache

WebSocket GatewayPersistent connections

Data Stores

PostgreSQLRelational DB

MySQLRelational DB

CassandraWide-Column DB

DynamoDBNoSQL / Managed

S3 BucketObject storage

Queues & Cache

Redis CacheIn-memory store

KafkaEvent stream

ZookeeperCoordination

Specialized

Bloom FilterProbabilistic set

Rate LimiterThrottling

Geohash ServiceGeospatial index

Trie ServerPrefix search

APNS / FCMPush notifications

AggregatorBatch / roll-up

Drag to canvas · Hover node for × to delete · Draw from handle to connect

⚡

Design your architecture

Drag components from the left panel · Connect them by drawing from a node handle · Hit Start Simulation to validate

🚨 INCIDENT

GoogleAppleHERE

Design the routing backend for a maps application. Given an origin and destination, compute the fastest route considering real-time traffic. Handle 100M route requests/day, map data updates every 5 minutes, and navigation sessions with turn-by-turn updates.

📥 Assigned to:You — Senior Engineer

SCALE LEVELS

10,000 RPS

Target: <500ms

100,000 RPS

Target: <200ms

1,000,000 RPS

Target: <100ms

GLOBAL SUCCESS RATE

100.0%

P99 LATENCY

45ms

Target: < 200ms

TOTAL RPS INGESTED0 / 11,000