Limits

Limits apply to the whole business, across all its keys. More keys don't add capacity.

Budget	Limit
Requests	300 a minute
Writes (part of the requests)	60 a minute
Availability lookups (part of the requests)	60 a minute
Requests running at once	5
Requests	50,000 a UTC day
Bookings created through the API	30 a minute, 500 a UTC day
Customer erasures	100 a UTC day
Other actions that email a guest, such as quick invites and booking changes	200 in any 24 hours
Webhook delivery attempts	20,000 a UTC day

Every response carries the minute budget it used:

X-RateLimit-Limit: 300
X-RateLimit-Remaining: 287
X-RateLimit-Reset: 41

X-RateLimit-Reset is in seconds.

When you hit a limit

Status	Code	What to do
429	`rate_limited`	Wait for `Retry-After` seconds
429	`concurrency_limited`	Wait for a running request to finish
429	`daily_quota_exceeded`	Wait for `Retry-After` seconds: until midnight UTC for daily budgets
503	`service_busy`	Wait for `Retry-After` seconds

Back off with jitter rather than retrying in a tight loop. If your integration needs more, contact Clearslot support: limits can be raised for a while.

Emails to the business

The business's owners get an email:

once a UTC day, when its integrations reach 80% of the daily request limit
once, when the API pauses because the business no longer has Pro or a complimentary grant

A paused business answers every request with 402 plan_required. Its keys and connected apps are kept, and they work again as soon as the business is back on Pro or has a complimentary grant.

Its webhook endpoints pause and resume the same way.