specification: API Commons Rate Limits
specificationVersion: '0.1'
schema: https://raw.githubusercontent.com/api-evangelist/interface-research/main/schema/api-commons.yml#/$defs/RateLimits
provider: Zcal
providerId: zcal
created: '2026-06-21'
modified: '2026-06-21'
reconciled: false
tags:
- Scheduling
- Calendar
- Booking
- Meetings
- Webhooks
- Rate Limiting
- Quotas
- Throttling
description: >-
  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.
notes: >-
  If Zcal publishes API or webhook delivery limits in the future, reconcile
  this artifact against the official documentation. As of 2026-06-21 no such
  limits are documented.
sources:
- https://help.zcal.co/integrations/webhooks
- https://help.zcal.co/integrations/webhooks/webhook-payload
- https://help.zcal.co/
responseCodes:
  throttled: not documented
limits:
- name: Inbound REST API Rate Limit
  scope: account
  metric: requests
  limit: not applicable
  notes: No documented public REST API, so no inbound API rate limit exists.
- name: Outbound Webhook Delivery
  scope: subscription
  metric: events
  limit: not documented
  notes: >-
    Zcal POSTs event.created / event.rescheduled / event.cancelled to your
    subscriber URL. No delivery rate, retry policy, or concurrency limit is
    documented.
policies:
- name: No Documented API Throttling
  description: >-
    Because Zcal exposes no public inbound REST API, there is no published
    throttling or quota policy to enforce against.
- name: Webhook Receiver Responsibility
  description: >-
    Subscribers should return a fast 2xx and process payloads
    asynchronously; verify the optional x-zcal-webhook-signature HMAC
    SHA-256 header to authenticate deliveries.
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com