Zcal · Rate Limits

Zcal Rate Limits

Zcal does not publish a general-purpose public REST API, and as a result there is no documented inbound API rate-limit policy (RPM / TPM / quotas) to reconcile. The primary programmatic surface is OUTBOUND webhooks, where Zcal POSTs booking lifecycle events to a subscriber URL you control; in that direction your own endpoint is the receiver, so any throughput limits are governed by the volume of bookings rather than an API quota. No public webhook delivery rate limit, retry schedule, or concurrency limit is documented at the sources reviewed.

Zcal Rate Limits is the machine-readable rate-limit profile for Zcal on the APIs.io network, conforming to the API Commons Rate Limits specification.

It captures 2 rate-limit definitions, measuring requests and events.

The profile also includes 2 backoff/retry policies defined and response codes documented for throttled.

Tagged areas include Scheduling, Calendar, Booking, Meetings, and Webhooks.

2 Limits Throttle: not documented
SchedulingCalendarBookingMeetingsWebhooksRate LimitingQuotasThrottling

Limits

Inbound REST API Rate Limit account
requests
not applicable
No documented public REST API, so no inbound API rate limit exists.
Outbound Webhook Delivery subscription
events
not documented
Zcal POSTs event.created / event.rescheduled / event.cancelled to your subscriber URL. No delivery rate, retry policy, or concurrency limit is documented.

Policies

No Documented API Throttling
Because Zcal exposes no public inbound REST API, there is no published throttling or quota policy to enforce against.
Webhook Receiver Responsibility
Subscribers should return a fast 2xx and process payloads asynchronously; verify the optional x-zcal-webhook-signature HMAC SHA-256 header to authenticate deliveries.

Sources

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Every rate limit here is available over the APIs.io API and to AI agents over MCP.

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Tools for rate limits

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  • find_rate_limitsBrowse and filter every rate limit in the catalog.
  • apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.
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Call it yourself

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This rate limit 
curl "https://apis.io/api/v1/rate-limits/zcal-rate-limits"
All rate limits 
curl "https://apis.io/api/v1/rate-limits?limit=25"

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