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: First Data (Fiserv)
providerId: first-data
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:
  - Payments
  - Merchant Services
  - Financial Services
  - Transaction Processing
  - Rate Limiting
description: Fiserv (parent of First Data) does not publish numeric rate limits for Commerce Hub or other developer APIs. Production throttling is set per merchant agreement and capacity profile. Standard HTTP 429/503 throttling responses apply, and idempotency is supported via Client-Request-Id headers on Commerce Hub APIs.
notes: No public RPS/RPM numbers documented at developer.fiserv.com. Per-merchant throttles are negotiated. Scaffold trimmed to one umbrella entry pointing to docs.
sources:
  - https://developer.fiserv.com/
  - https://developer.fiserv.com/product/CommerceHub/docs/?path=docs/Resources/Guides/Idempotency.md
  - https://docs.fiserv.dev/public/reference/apis
headers:
  requestId: Client-Request-Id
  retryAfter: Retry-After
responseCodes:
  throttled: 429
  serviceUnavailable: 503
limits:
  - name: Commerce Hub / Carat per-merchant throttle
    scope: merchant/api-key
    metric: varies
    limit: per-merchant agreement; not publicly published
    applies:
      - Fiserv Commerce Hub
      - Fiserv Carat
      - Fiserv Developer (First Data Legacy)
policies:
  - name: Idempotency
    description: Commerce Hub supports idempotency via Client-Request-Id; retries with the same key return the original response within the idempotency window.
  - name: Backoff Strategy
    description: Clients should implement exponential backoff with jitter on 429 / 5xx responses and honor Retry-After when present.
  - name: Per-Merchant Throttling
    description: Throttles are sized per merchant onboarding; raise limits via Fiserv account/support team rather than self-service.
  - name: Settlement Cutoff Pressure
    description: Volume near daily settlement cutoffs may experience tighter throttling; size batches and retries accordingly.
maintainers:
  - FN: Kin Lane
    email: kin@apievangelist.com