Problems / Design a product, medium
Design Pinterest from an empty canvas: an image-heavy home feed through a CDN, pin saves and search, with scrapers kept out, at 2,500 requests a second.
Unlock it once for 15 credits; everything inside it is free (runs, changes, Submit, results, hints). Sign in with Google to start; new accounts get free credits.
Request types to route: image (50%, read), feed (25%, read), search (15%, read), save (10%, write). Budget: $14,000 a month.
You start from an empty canvas. When you run the tests, each one simulates your design with its own traffic and failures:
| Test | What it does | Passes when |
|---|---|---|
| Normal day | The normal day: the traffic in the brief, nothing broken. | Success ≥ 99.5%; p99 latency ≤ 300 ms (image); p99 latency ≤ 400 ms (feed); p99 latency ≤ 500 ms (search) |
| Holiday season | At 5 s holiday planning peaks: traffic doubles for 8 s. | Success ≥ 99%; p99 latency ≤ 500 ms (feed) |
| Cache flushed | At 5 s the cache on the request path is emptied, as after a restart or a bad deploy. | Success ≥ 99%; p99 latency ≤ 500 ms (image) |
| Scrapers | At 5 s 4,000 requests a second of scraping traffic arrive for 10 s, alongside real users. | Attack blocked ≥ 85%; Success ≥ 99% |
| Budget: $14,000/month | The normal day's design must cost at most $14,000 a month. | Cost ≤ $14,000/month |