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: CME Group
providerId: cme-group
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:
  - Capital Markets
  - Derivatives
  - Market Data
  - Rate Limiting
notes: CME Group's MDP 3.0 market-data feed and iLink order-routing protocol are not classic REST APIs;
  message-rate governance is enforced via session-level Message Per Second (MPS) caps documented in the
  iLink technical documentation and via market-data session multicast group allocation. Public REST APIs
  (e.g. CME DataMine catalog) enforce platform-wide throttling but do not publish a numeric per-second
  ceiling.
description: 'CME Group enforces message-rate governance at the protocol level: per-session MPS caps for
  iLink order entry, market-data multicast group allocations for MDP 3.0, and platform-wide throttling
  for the CME DataMine REST surface. Specific numeric ceilings are documented inside the iLink and MDP
  technical specs distributed to authorized customers.'
sources:
  - https://www.cmegroup.com/confluence/display/EPICSANDBOX/iLink+3+Order+Entry+Messaging
  - https://www.cmegroup.com/market-data/distributors-and-vendors.html
responseCodes:
  throttled: 429
  serviceUnavailable: 503
limits:
  - name: iLink session — Messages Per Second
    scope: session
    metric: messages_per_second
    limit: see iLink technical specification
    notes: CME Globex enforces a per-session MPS cap on order entry; the cap is allocated per session at
      onboarding and is documented in the iLink 3 / iLink 2 technical spec.
  - name: MDP 3.0 market-data feed
    scope: subscriber
    metric: messages_per_second
    limit: not throttled — multicast feed
    notes: MDP 3.0 is a UDP multicast feed; consumers are expected to keep up with the wire rate. There
      is no per-consumer throttling.
  - name: CME DataMine REST API
    scope: account
    metric: requests_per_minute
    limit: see DataMine API documentation
    notes: REST surface for downloading historical / reference data. Throttling is enforced at the platform
      level.
policies:
  - name: iLink MPS allocation
    description: Each iLink session is allocated a Messages-Per-Second cap at onboarding. Exceeding the
      MPS cap results in messages being rejected with a session-level reject code; sustained over-subscription
      requires escalation through the customer's clearing firm.
  - name: Market-data feed pacing
    description: MDP 3.0 is a real-time multicast feed; consumers must size hardware to keep up with peak
      message rates. CME publishes capacity guidance for each product group.
  - name: Authorized-customer documentation
    description: Detailed message-rate ceilings, retry semantics, and session-level reject codes are documented
      in the iLink and MDP technical specifications distributed to authorized customers and vendors.
maintainers:
  - FN: Kin Lane
    email: kin@apievangelist.com