Rate limits

Limits protect the venues behind the router and keep free keys free. Over the limit means blocked, never billed: there is no overage charge, ever.

The limits

Higher keyed limits exist for partners; email info@cayvox.com.

Headers

Keyed responses carry the current window's state:

x-ratelimit-limit: 600
x-ratelimit-remaining: 599

Captured from production 2026-07-03 with a temporary key.

On 429 you also get Retry-After: the seconds until the next minute window opens. A real capture is on the errors page.

Approximate under concurrency, honestly

The counters are fixed one-minute windows on distributed storage. Under concurrent bursts the count is approximate: a short burst may briefly exceed the nominal number before the limiter catches up, and the boundary between two windows admits up to two windows' worth in a short span. Treat the limit as an operating envelope, not a precise contract. What IS precise: over the limit blocks with 429 and is never billed.

Client guidance

• Respect Retry-After; do not tight-loop on 429.
• Quotes are edge-cached about 10 seconds per parameter combination, so polling faster than that returns the same numbers anyway. Only a cache MISS (a fresh parameter combination) spends the keyless fresh-quote budget; repeating recent combinations never does.
• One key per product. Sharing a key across products makes one product's burst the other's 429.