ACID Isolation Locking Lab
Simulate a checkout race to see how ACID isolation, row locks, table locks, MVCC snapshots, range locks, and serializable retries keep database state correct.
Simulators
Browse all browser-based simulators for failure modes, production behavior, reliability, scaling, and backend system design.
21 simulators
All Simulators 21 simulators
Auto-Scaling (HPA) Simulator
Simulate Kubernetes Horizontal Pod Autoscaler scaling pod replicas based on CPU utilization. Watch pods spin up and down as traffic changes, experiment with scaling thresholds
Auto-Scaling Component Runtime Simulator
Test Kubernetes HPA autoscaling as explicit runtime components with parent-owned input ports, child injection, routed connector messages, component state, element state, controls
B-Tree Indexing Enhanced Simulator
Test database B-Tree indexing as explicit runtime components with parent-owned input ports, child injection, routed connector messages, buffer pool caching, and query planning.
Cache Invalidation Strategies Simulator
Simulate different cache invalidation strategies side-by-side. Watch how write-through, write-behind, cache-aside, and TTL-based invalidation handle reads, writes
Cascading Timeout & Latency Injection
Analyze cascading failure propagation across microservices when latency or errors are injected, and test mitigation strategies using circuit breakers and retry limits.
CDN Edge Caching Simulator
Simulate a CDN with multiple edge PoPs, an origin shield, and an origin server. Watch cache hits, misses, SWR revalidations
Circuit Breaker Pattern Simulator
Simulate the Circuit Breaker pattern with count-based and time-based sliding windows, slow-call rate thresholds, fallback components, and per-component details. Watch requests flow, timeout
Database Connection Pool Simulator
Simulate a database connection pool managing connections between application threads and a database. Watch connections get checked out, used, and returned. Experiment with pool sizing
Feature Flag Rollout Simulator
Simulate feature flag rollout strategies. Watch how percentage-based rollouts, user targeting, and kill switches control which users see new features.
Kubernetes Autoscaling Under Load
Simulate Horizontal Pod Autoscaler (HPA) and Cluster Autoscaler (CA) behavior under traffic spikes. Experiment with metrics collection lag, pod cold start delays (image pull and app boot)
Load Balancer Crash Simulator
Experiment with HA failover, stale DNS/client caches, backend health checks, fail-open routing, overload, latency, and recovery when a load balancer crashes.
Rate Limiting Simulator
Experiment with token bucket rate limiting by changing request rate, bucket capacity, refill rate, and scenarios such as normal traffic, bursts, overload, and recovery.
Reactive Architecture Builder
Build a typed software architecture, change realistic capacity settings, and watch overload, backpressure, and Kubernetes recovery propagate through the system.
Redis Crash & Cache Stampede
Simulate what happens when Redis crashes: cache timeouts, database fallback, cache stampede pressure, rising latency, 5xx errors, and recovery after Redis restarts cold.
Ride-Sharing Service (Uber/Lyft)
Explore geospatial indexing (Geohash vs QuadTree), real-time driver coordinates streaming, surge pricing dynamic feedback loops, and transactional trip matching states.
SLO / Error Budget Burn Rate Simulator
Simulate SLOs and error budgets to see how traffic, failures, burn rates, alert thresholds, and feature freezes affect reliability decisions.
Stock Exchange System Design
Explore LMAX Disruptor sequencing, pre-trade risk validations, FIFO Limit Order Book matching, UDP multicast publishers, and market circuit breakers.
Surviving a Redis Crash
Walk through a Redis crash from healthy reads to degraded fallback, DB protection, circuit breaking, L1 hot keys, replica failover, gradual warm-up, and cache-optional correctness.
TCP Congestion Control
Simulate TCP congestion control mechanisms. Watch packets flow and observe Slow Start, Congestion Avoidance, and Fast Retransmit phases. Experiment with packet loss, latency
Tunable DB Consistency Simulator
Simulate tunable read/write consistency levels (One, Quorum, All) in a Dynamo-style replicated database ring. Slice network connections to create partitions, execute operations