Active Learning
Build and test systems directly in the browser so concepts turn into intuition faster.
System Design Platform · v2.0
System design is the ceiling for most engineers. We make it the floor.
Structured problem sets, an in-browser diagram canvas, and guided case studies - built for engineers who already know how to code.
Built in public - early access opens in small weekly waves
Priya S.solvedConsistent Hashing2m agoAlex M.hit a14-day streak5m agoJordan K.passed a Staff interview atStripe12m agoMarcus T.solvedRate Limiter Design1m agoSarah L.completedCDN Architecture module8m agoChris W.is on a22-day streakjust nowNeha R.solvedDistributed ID Generator4m agoKevin B.passed a Senior interview atMeta18m agoRavi P.masteredCAP Theorem deep dive6m agoLily C.solvedEvent Sourcing Architecture9m agoOmar H.passed a Principal interview atCloudflare22m agoAnya V.hit a30-day streak14m ago
// the problem
Leetcode taught you to code. Nobody taught you to think at scale.
System design interviews separate senior engineers from staff — and most preparation resources are shallow, disconnected, or purely theoretical. You don't need another blog post about Twitter's architecture. You need a place to actually practice building systems, breaking them under load, and articulating tradeoffs out loud.
73%of engineers fail system designdespite passing every coding round
6 wksaverage prep time neededfor a single staff-level loop
0mainstream platformswith structured, interactive SD practice
// the platform
Four tools. One coherent system for getting interview-ready.
01 / Canvas
Build real architectures in the browser. No whiteboard required.
Drag, connect, and annotate system components on a fully interactive canvas. Design a CDN, a message queue, or an entire microservices topology — then get structural feedback before you step into the room.
twitter-timeline.sysiq
7 nodes · 9 edgesSave
CursorNodeEdgeLabelComment
100%
Load Balancer
App Server 1
App Server 2
App Server 3
Redis Cache
PostgreSQL
Properties
Redis Cache
Typecache
Version7.2.4
Port6379
Replicas3
Memory16 GB
DeleteDup.
02 / Case Studies
Walk through real architectures, decision by decision.
Guided, step-by-step breakdowns of Twitter's timeline feed, Uber's dispatch system, Discord's message fanout, and more. Not summaries — structured deep dives with embedded questions at every tradeoff point.
Case Study · Twitter
Design Twitter's Timeline Feed
Step 3 of 8
✓Requirements & Scale Estimation
✓High-Level Architecture
→Fanout on Write vs Read
○Timeline Storage Schema
○Cache Strategy & Invalidation
○Handling Celebrity Accounts
~42 min remaining
03 / Problem Bank
150+ problems organised by domain, difficulty, and company.
Consistent Hashing to CRDT, Rate Limiters to Service Mesh. Every problem includes back-of-envelope estimations, architectural constraints, and a structured solution rubric used by actual staff-level interviewers.
AllDistributedStorageMessagingReal-timeAuth
HardConsistent HashingDistributed
MediumDesign a Rate LimiterInfra
HardEvent SourcingMessaging
HardDistributed CacheStorage
EasyPush Notification SystemMessaging
Showing 5 of 150+View all →
04 / Simulator
Timed mock sessions with AI-powered structural feedback.
Simulate a real staff-level system design interview: 45-minute timer, intentionally ambiguous requirements, and an AI evaluator that scores your solution on scalability, consistency, and availability tradeoffs.
Mock Interview · Staff Level
23:47
Question
“Design a real-time collaborative editing system. Assume 10M DAU with up to 500 simultaneous editors on a single document.”
AI Evaluator
△
Scalability: Missing horizontal sharding strategy
✓
Consistency: Good — CRDT approach correctly identified
△
Availability: Needs more on multi-region failover
// problem bank
See what you're actually solving.
Every problem includes back-of-envelope estimations, structured tradeoff rubrics, and reference solutions reviewed by engineers who've cleared staff-level loops at top companies.
8 free · 24 total
Design a Rate Limiter
MediumDistributed Systems
Google · Stripe
Consistent Hashing
HardDistributed Systems
Amazon · Discord
Design a URL Shortener
EasyStorage
Google · Meta
Design a Message Queue
MediumMessaging
LinkedIn · Uber
CDN Architecture
HardDistributed Systems
Cloudflare · Netflix
Real-time Chat System
MediumReal-time
Slack · Discord
OAuth 2.0 + Session Management
MediumAuth
Okta · GitHub
Distributed Cache (Redis)
HardStorage
Twitter · Pinterest
Search Autocomplete System
MediumDistributed Systems
Google · Yelp
File Storage System (S3-like)
HardStorage
Dropbox · Box
Push Notification System
EasyMessaging
Facebook · Apple
WebSocket Scaling
HardReal-time
Twitch · Discord
API Gateway Design
MediumDistributed Systems
Netflix · Kong
JWT + Token Refresh Flow
EasyAuth
Auth0 · Stripe
Event Sourcing Architecture
HardMessaging
Confluent · Shopify
Distributed ID Generator
MediumDistributed Systems
Twitter · Instagram
Database Sharding Strategy
HardStorage
YouTube · Airbnb
Live Location Tracking
HardReal-time
Uber · Lyft
Zero-Trust Auth Architecture
HardAuth
Okta · Cloudflare
Presence & Typing Indicators
MediumReal-time
Slack · Notion
Dead Letter Queue Design
MediumMessaging
AWS · RabbitMQ
Raft Consensus Implementation
HardDistributed Systems
CockroachDB · etcd
Time-Series Database
HardStorage
InfluxDB · Datadog
Multi-Region Failover
HardDistributed Systems
Stripe · Cloudflare
Showing 24 of 150+ problems
View all →// diagram canvas
Design systems visually. In the browser. Right now.
No Lucidchart. No Miro. No setup. A purpose-built canvas that understands the difference between a cache and a message queue and helps you reason about it.
Sysiq/canvas/twitter-timeline-v3
Auto-saved 2s agoShareExport
100%
Redis Cache selected
Load Balancer
App Server 1
App Server 2
App Server 3
Redis Cache
Message Queue
PostgreSQL
Properties
Redis Cache
cache · node_07Typecache
EngineRedis 7.2
Port6379
Replicas3
Memory16 GB
Evictionallkeys-lru
TTL86400s
Clusterenabled
Connections
â†App Server 1
â†App Server 2
→PostgreSQL
7 nodes · 9 edgestwitter-timeline-v3
ValidatedLast edit 2s ago
No whiteboard needed
Everything runs in the browser. Open a problem and start drawing within seconds.
Typed components
Every node knows its role. Caches, queues, databases, and gateways each have distinct validation rules.
Structural feedback
The canvas checks your design for common architectural anti-patterns as you build.
// leaderboard + progress
Real engineers. Real momentum. Real pressure.
A global leaderboard, daily streaks, and domain mastery badges — built to keep senior engineers accountable without feeling like a language-learning app.
Global LeaderboardThis week
1
SK
Sarah K.
Staff Eng · Shopify
2,840
47-day streak
2
MT
Marcus T.
Senior Eng · Coinbase
2,610
31-day streak
3
NR
Neha R.
Senior Eng · Cloudflare
2,390
28-day streak
4
5
You
You are currently ranked #47+3 todayCurrent Streak
14
days
Personal best: 22
M
T
W
T
F
S
S
Domain Badges4 / 8 earned
Caching Master
Storage
Consistency Expert
Distributed
Load Balancing Pro
Infra
Storage Architect
Storage
Messaging Guru
Messaging
Real-time Builder
Real-time
Security Specialist
Auth
Distributed Systems
Distributed
Live Activity
Last 30 minPriya S.solvedConsistent Hashing
2m agoAlex M.hit a14-day streak
5m agoJordan K.passed a Staff interview atStripe
12m agoMarcus T.solvedRate Limiter Design
1m agoSarah L.completedCDN Architecture module
8m agoNeha R.solvedDistributed ID Generator
4m agoKevin B.passed a Senior interview atMeta
18m agoRavi P.masteredCAP Theorem deep dive
6m agoPre-launchcurrently open to early users
Weeklynew labs and content updates
Hands-onlearn by interacting, not only reading
Interview-firstfocused on real architecture tradeoffs
// why this workflow works
Structured Depth
Progress from fundamentals to advanced distributed system decisions with a guided path.
Practice Loop
Reinforce what you learn using quizzes, mocks, and retrieval-based practice sessions.
Roadmap focus before public launch
More guided case studiesExpanded mock interview flowsCompany-style question tracksDeeper production tradeoff scenarios
// curriculum
Everything that matters. Nothing that doesn't.
70topics across 8 domains
The full breadth of what a staff-level engineer is expected to know. Organised by domain so you can identify and close specific gaps rather than re-covering ground you already own.
Distributed Systems
Consistent HashingCAP TheoremCRDTRaft ConsensusPaxosVector ClocksTwo-Phase CommitSaga PatternLeader ElectionGossip ProtocolQuorum Reads/WritesDistributed Transactions
Caching
LRU / LFU EvictionCache Invalidation StrategiesWrite-through vs Write-behindCDN Edge CachingRedis Cluster ModeMemcached ArchitectureCache Stampede PreventionRead-through CacheThundering Herd Problem
Storage
B-Tree IndexingLSM TreeColumn-Oriented StoresSharding StrategiesReplication LagWrite-Ahead Log (WAL)MVCCBloom FiltersHyperLogLogTime-Series Storage
Messaging
Kafka PartitioningEvent SourcingCQRSPub/Sub PatternsMessage Ordering GuaranteesDead Letter QueuesExactly-Once DeliveryBackpressure HandlingOutbox Pattern
Networking & APIs
Load Balancing AlgorithmsAPI Gateway PatternsCircuit Breaker PatternRate Limiting AlgorithmsService DiscoverygRPC vs REST vs GraphQLGraphQL FederationReverse Proxy Design
Real-time Systems
WebSocket ScalingLong Polling vs SSEWebRTC SignalingPresence SystemsOperational TransformationCRDT for CollaborationFan-out Architecture
Security & Auth
OAuth 2.0 FlowsJWT Internals & PitfallsmTLSZero-Trust ArchitectureAPI Key ManagementRBAC vs ABACSession vs Token AuthPKCE Flow
Infrastructure
Service Mesh (Istio/Envoy)Container OrchestrationBlue/Green DeploymentsChaos EngineeringObservability (Logs, Metrics, Traces)Multi-Region ArchitectureEdge Computing Patterns
Can't find a topic? We add 4–6 new problems and deep dives every month — community-voted, reviewer-approved, and shipped with full solution rubrics.
// pricing
One decision. No traps.
Start free and begin solving immediately. Paid plans will return once checkout is fully integrated.
Free
$0forever
Enough to know if this is worth your time.
15 problems unlocked, no time limit
In-browser diagram canvas (read-only templates)
Community leaderboard access
No case studies
No interview simulator
No streak tracking or badges
No credit card required. Billing options will appear after payments launch.
// get started
The engineers who get staff offers didn't get lucky.
They just prepared differently.
Stop reading architecture summaries. Start building systems, breaking them under load, and articulating tradeoffs with precision. That's what the interview tests — and that's exactly what Sysiq trains.
No credit card. No setup. First problem in under 60 seconds.