Litmus · Rate Limits
Litmus Rate Limits
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 [email protected]) 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.
4 Limits
Throttle: 429
Rate LimitingEmail TestingDeveloper Tools
Limits
Partner API rate limit api-key
see partner agreement
Numeric ceilings are not published; configured per partner.
Bulk delete batch size request
1000
The delete email endpoint accepts up to 1,000 email_guid values per request.
Uploaded email retention window resource
48
Uploaded emails remain available for 48 hours for requesting new captures (functional limit, not a rate limit).
Preview image retention resource
180
Preview image data persists for 180 days (functional limit, not a rate limit).
Policies
Partner program access
Litmus Instant API access is evaluated case-by-case; reach [email protected] to start the conversation.
Asynchronous capture
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.
Backoff Strategy
Implement exponential backoff with jitter on 429 / 5xx, and honor Retry-After when returned.