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: Litmus
providerId: litmus
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:
  - Rate Limiting
  - Email Testing
  - Developer Tools
description: Litmus does not publish numeric request-per-second / per-minute rate limits for the Litmus
  Instant API. Access is partner-program-gated (evaluated case-by-case via partners@litmus.com) and
  per-partner throttling is configured under the partner agreement. The docs do publish performance
  expectations and resource constraints (preview generation latency, retention windows, batch sizes)
  rather than rate ceilings.
notes: No public per-second / per-minute rate-limit numbers found. Partner-specific throttling is governed
  by the Litmus partner agreement.
sources:
  - https://docs.litmus.com/instant
responseCodes:
  throttled: 429
  serviceUnavailable: 503
limits:
  - name: Partner API rate limit
    scope: api-key
    metric: varies
    limit: see partner agreement
    notes: Numeric ceilings are not published; configured per partner.
  - name: Bulk delete batch size
    scope: request
    metric: ids_per_request
    limit: 1000
    notes: The delete email endpoint accepts up to 1,000 email_guid values per request.
  - name: Uploaded email retention window
    scope: resource
    metric: hours
    limit: 48
    timeFrame: hour
    notes: Uploaded emails remain available for 48 hours for requesting new captures (functional limit,
      not a rate limit).
  - name: Preview image retention
    scope: resource
    metric: days
    limit: 180
    timeFrame: day
    notes: Preview image data persists for 180 days (functional limit, not a rate limit).
policies:
  - name: Partner program access
    description: Litmus Instant API access is evaluated case-by-case; reach partners@litmus.com to start
      the conversation.
  - name: Asynchronous capture
    description: Email client screenshots return within seconds (typical 3–11s depending on client);
      Instant Preview test creation takes ~600ms to issue an email_guid. Design clients to poll or use
      callbacks rather than block on synchronous responses.
  - name: Backoff Strategy
    description: Implement exponential backoff with jitter on 429 / 5xx, and honor Retry-After when
      returned.
maintainers:
  - FN: Kin Lane
    email: kin@apievangelist.com