InfraSim is a system design game you play with your thumbs. Build a cloud architecture on a canvas, deploy it, and watch simulated traffic tear through whatever you got wrong.
Drag a load balancer, a cache, a database and a queue onto the canvas. Wire them together. Hit deploy. Latency, cost and error rate move because of the architecture you designed, not because a script said so.
Then something breaks. A traffic spike lands at the worst moment. A zone goes dark. A bot swarm hammers your login endpoint. Latency climbs, the queue backs up, and you have seconds to find the bottleneck, scale the right tier and keep users online, or read an incident postmortem explaining exactly what took you down.
WHAT YOU PLAY
• Campaign: a guided system design course, 44 levels across 10 chapters, from "one server, one database" to multi-region, cache-fronted, queue-buffered cloud architecture.
• Startup Survival: an endless run where each incident escalates until your architecture finally gives.
• Daily Challenge: one seeded scenario, one shot, a global leaderboard.
• Sandbox: no scoring, no rules. Build any cloud architecture you want, then stress test it until it falls over.
• Learn: an encyclopedia of the concept behind every service, for people who have never touched a terminal.
A SIMULATION, NOT A QUIZ
Every run is a working model of a distributed system. Traffic, queueing curves, capacity, replication, latency, cost and cascading failure are simulated on your device from the architecture you built. Same seed, same run, every time.
There is no single correct answer. Most levels have several viable designs with real trade-offs, which is what system design looks like in a real interview and on a real on-call rotation.
WHAT YOU LEARN
Load balancing, health checks, and why a load balancer cannot save a saturated database. Horizontal versus vertical scaling. Caching and cache invalidation. Read replicas and database sharding. Message queues and back-pressure. CDNs and edge caching. Rate limiting and DDoS absorption. Multi-region failover. Database connection limits, and why they are what actually kills you at 3am.
And the cost of each decision, because a cloud architecture that survives any load at any price is not a good answer.
This is devops and SRE thinking taught by breaking things: more real incident timelines than most site reliability courses, each generated from the system you built rather than written in advance.
WHO IT IS FOR
Backend engineers who have never owned a production system. Students who can write code but have never watched a database saturate. Anyone preparing for a system design interview who would rather build ten architectures than read another diagram. Anyone who likes watching a distributed system come apart and working out why.
No prior devops experience assumed. No terminal, no YAML, no cloud bill.
FREE, GENUINELY
The tutorial, 12 of the 44 campaign levels, today's Daily Challenge, three Sandbox slots and the whole Learn encyclopedia are free, with no account needed. Sign in only if you want progress to follow you across devices and a place on the leaderboard.
No ads. No loot boxes. No energy timers. Ever.
InfraSim is an independent educational game, not affiliated with, endorsed by, or sponsored by Amazon Web Services, Microsoft, or Google. Provider names only map generic architecture concepts onto terminology you may recognise.
SUBSCRIPTION
InfraSim Pro is available as a monthly or annual auto-renewing subscription, or as a one-time lifetime unlock. Payment is charged to your Google Play account at confirmation of purchase. A subscription renews automatically unless it is cancelled at least 24 hours before the end of the current period. Manage or cancel any time at Google Play > Menu > Subscriptions, or from Settings inside the app.
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Cloud architecture simulator: design real systems, deploy, and watch them break.