Problems / AI products, medium

Content moderation queue

Every post is checked by a moderation model with 30 slots, about 600 ms per post, at 80 posts a second.

Free to open. Runs in your browser, no sign-up.

Your goals

Success ≥ 99%, p99 ≤ 5 s.

The traffic

80 requests a second for 30 seconds: 100% request (reads).

The system

What each component does in this design, and what calls it. The simulator mimics each one from these settings.

ComponentIts job hereSettings
Load balancerLoad balancerTraffic enters here.Calls AI app.Layer 4 balancers route by IP and port; layer 7 balancers read HTTP and can route by path or header.–
AI appApp serviceLoad balancer forwards to it.Calls Moderation model.Little's law: throughput ≈ concurrency ÷ latency. 200 slots at 50 ms serve about 4,000 req/s.3 replicas × 500 slots · timeout 30 s
Moderation modelLLM-as-judgeAI app calls it.An LLM judge grades outputs at scale, but it is another model call with its own latency, cost and biases.30 slots

Hints

Try it first. Open one hint at a time if you get stuck.

Hint 1

80 × 0.6 s = 48 in flight.

Hint 2

Find the red card first, then its capacity: slots ÷ seconds per request.

One way to solve it

Give the moderation model more capacity.

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