A product launch drives 126,000 requests per minute. One API server handles 500 r/s; scaled to the maximum (×4) it reaches 2,000 r/s — still not enough. The only way forward is to break through the single-machine ceiling with a fleet behind a Load Balancer.
Requirements
Functional
·Serve sustained (not transient) product-launch traffic across a fleet of app servers
Non-functional
·~2,100 requests/sec
·95% reads
·p99 latency ≤ 200ms
·99% availability
Constraints
·Budget: $35/hr or less
·One node's vertical ceiling (500 r/s × 4 instances = 2,000 r/s) is not enough on its own — fan-out across multiple nodes is required
Out of scope
·Multi-region deployment
TrafficRequests per second — the rate of incoming traffic this level throws at your system.
~2100 r/s · read-heavy
95% reads · 5% writesWhat fraction of requests are reads (fetches) vs writes (updates) — this decides which components sit on the hot path.
Win conditions
p99 latency99% of requests finish at or under this time — a stricter tail-latency bar than p95 that catches worst-case slowness.≤ 200ms
availabilityThe share of legitimate requests that succeeded, out of everything sent your way. 99% still means 1 in 100 users saw an error.≥ 99%
throughputHow many requests per second your system actually completed — not requested, completed.≥ 1500 r/s
error rateThe share of requests that failed outright: timeouts, drops, or capacity overload.≤ 2%
costWhat your architecture costs to run per hour, based on the instances and components you've wired up.≤ $35/hr
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Drag components from the right → connect their handles → Run.
Drag onto canvas
Components
Client
ClientWhere traffic originates.
Compute
API GatewayFront door — the app tier requests pass through.
500 r/s · 20ms · $2/hr
BackendA second compute tier for heavier processing.
350 r/s · 25ms · $2/hr
Storage
SQL DatabaseRelational store. Durable, but the lowest throughput.
200 r/s · 50ms · $3/hr
NoSQL DB3× the throughput of SQL — at a premium. Pay for it only when the load demands it.
600 r/s · 30ms · $4/hr
Redis CacheIn-memory read-cache — absorbs repeated reads. Useless for writes.
5000 r/s · 3ms · $2/hr
Read Replica
200 r/s · 55ms · $3/hr
Lvl 12
DB Standby
200 r/s · 50ms · $3/hr
Lvl 13
Networking
CDNEdge read-cache — serves content near the user.
50000 r/s · 5ms · $1/hr
Load BalancerManaged, premium front door — highest ceiling, lowest latency, costs more.
10000 r/s · 2ms · $2/hr
Reverse ProxyCheaper self-hosted front door — lower ceiling, the smart buy under 8,000 r/s.
8000 r/s · 3ms · $1/hr
Messaging
QueueACKs writes instantly, drains them to storage — absorbs bursts, not sustained overload.