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: Photon Engine
providerId: photonengine
created: '2026-07-03'
modified: '2026-07-03'
reconciled: false
tags:
- Gaming
- Multiplayer
- Realtime
- Rate Limiting
- Fair Use
description: >-
  Photon does not rate-limit its Realtime transport protocol the way a REST
  API throttles requests per minute. Instead, capacity is governed by the
  purchased Concurrent Users (CCU) plan (see plans/photonengine-plans-pricing.yml),
  and Photon publishes a fair-use guideline - not a hard-enforced cap - on
  messages per second per room, plus hard technical limits on message size
  and unreliable-command buffering. The Room Lifecycle WebHooks and Custom
  Authentication HTTP callbacks (outbound from Photon to the developer's
  server) are not documented with an explicit rate limit, but respond within
  the same room-join / operation flow they are triggered from, so slow
  webhook responses can delay gameplay operations.
notes: >-
  Photon states it "does not enforce" the messages-per-second guideline but
  relies on a fair-use policy and may act against rooms that greatly exceed
  it; there is no published numeric SLA for webhook or custom-auth response
  time, though slow responses will be perceived as latency by connected
  clients.
sources:
- https://doc.photonengine.com/realtime/current/reference/performance-tips
- https://forum.photonengine.com/discussion/12597/message-limits-per-room-enforced
- https://gist.github.com/bddckr/c4c287451a0a36568353ce9ec0582eaa
- https://doc.photonengine.com/realtime/current/gameplay/web-extensions/webhooks
responseCodes:
  operationFailed: non-zero returnCode on an Operation Response
  webhookFailed: non-zero ResultCode on a WebHook / Custom Authentication response
limits:
- name: Messages Per Second Per Room (fair use)
  scope: room
  metric: messages
  limit: 500
  notes: >-
    Photon recommends keeping combined inbound+outbound messages per second
    per room under ~500; not hard-enforced, but rooms that greatly exceed it
    are subject to Photon's fair-use policy and may be throttled or the
    account contacted.
- name: Concurrent Users (CCU)
  scope: application
  metric: concurrent_users
  limit: see plans/photonengine-plans-pricing.yml
  notes: >-
    The actual capacity ceiling is the purchased CCU plan; exceeding it can
    cause connection refusals until the plan is upgraded or CCU Burst (500+
    CCU plans) absorbs the spike.
- name: Message / Payload Size
  scope: connection
  metric: bytes
  limit: 1200
  notes: >-
    Messages larger than ~1.2 KB (including protocol overhead) are split
    across multiple UDP packets by the client SDK.
- name: Per-Client Buffer Size
  scope: connection
  metric: bytes
  limit: 500000
  notes: >-
    On Photon Cloud, a client that fills its outgoing buffer (roughly
    500 KB) in a short period is disconnected by the server.
- name: Unreliable Command Queue
  scope: connection
  metric: commands
  limit: 20
  notes: LoadBalancingPeer.LimitOfUnreliableCommands defaults to 20 queued unreliable commands.
policies:
- name: Fair Use, Not Hard Throttling
  description: >-
    Photon Realtime relies on a fair-use policy for messages-per-second
    rather than issuing HTTP-style 429 responses; there is no request-based
    throttling because there is no request-response REST surface for
    gameplay traffic.
- name: CCU Burst
  description: >-
    500+ CCU plans include a temporary burst allowance above the plan's CCU
    ceiling at no extra charge, smoothing short spikes without a hard cutoff.
- name: WebHook / Custom Auth Timeout Sensitivity
  description: >-
    Because WebHooks and Custom Authentication are called synchronously
    within a room-join or property-change operation, a slow-responding
    developer-hosted endpoint is experienced by players as added latency or
    a failed operation rather than a rate-limit error.
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com