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: Cisco Expressway
providerId: cisco-expressway
created: '2026-05-04'
# Provenance stamped 2026-08-11: this artifact was written by the API Evangelist
# bulk sweep dated 2026-05-04, not harvested from the provider. See roadmap#35.
method: generated
modified: '2026-05-05'
reconciled: false
tags:
  - Collaboration
  - Unified Communications
  - Video Conferencing
  - Rate Limiting
description: Cisco Expressway is a customer-deployed appliance/VM. Per-API request rate limits are not
  publicly documented as cloud-style quotas; throughput is bounded by the appliance's hardware/VM sizing
  (Small / Medium / Large) and by call/registration capacity defined in the Cisco Expressway Administrator
  Guide. Login throttling and SIP/H.323 traversal limits are managed via per-zone and per-domain settings
  in the Expressway configuration UI rather than a uniform request-per-second policy.
notes: Replace once Cisco publishes machine-readable rate-limit documentation for the Expressway REST
  and XML APIs. Numbers below are placeholders pending verification.
sources:
  - https://www.cisco.com/c/en/us/support/unified-communications/expressway-series/products-installation-and-configuration-guides-list.html
  - https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/expressway/admin_guide/X14-3/exwy_b_cisco-expressway-administrator-guide-x14-3.html
responseCodes:
  throttled: 429
  serviceUnavailable: 503
limits:
  - name: REST API requests
    scope: appliance
    metric: varies
    limit: see Expressway Administrator Guide for capacity per appliance size
  - name: SIP / H.323 traversal calls
    scope: appliance
    metric: concurrent_calls
    limit: see Cisco Expressway capacity datasheet (Small / Medium / Large)
policies:
  - name: Capacity-bounded
    description: Limits are bounded by the Expressway VM/appliance size and Smart Licensing entitlement,
      not by a cloud-style per-second API throttle.
  - name: Backoff Strategy
    description: Clients should implement exponential backoff with jitter on HTTP 429/503 responses
      from the REST or XML configuration APIs.
  - name: Administrative Throttles
    description: Login throttling, registration restrictions, and per-zone bandwidth caps are configured
      by the appliance administrator and override default behavior.
maintainers:
  - FN: Kin Lane
    email: kin@apievangelist.com