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 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.

Litmus Rate Limits is the machine-readable rate-limit profile for Litmus on the APIs.io network, conforming to the API Commons Rate Limits specification.

It captures 4 rate-limit definitions, measuring varies, ids_per_request, hours, and days.

The profile also includes 3 backoff/retry policies defined and response codes documented for throttled and serviceUnavailable.

Tagged areas include Rate Limiting, Email Testing, and Developer Tools.

4 Limits Throttle: 429
Rate LimitingEmail TestingDeveloper Tools

Limits

Partner API rate limit api-key
varies
see partner agreement
Numeric ceilings are not published; configured per partner.
Bulk delete batch size request
ids_per_request
1000
The delete email endpoint accepts up to 1,000 email_guid values per request.
Uploaded email retention window resource
hours · hour
48
Uploaded emails remain available for 48 hours for requesting new captures (functional limit, not a rate limit).
Preview image retention resource
days · day
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 partners@litmus.com 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.

Sources

Work with this as data

Every rate limit here is available over the APIs.io API and to AI agents over MCP.

MCP server

One button, every client — Claude, Cursor, VS Code and the rest.

https://apis.io/mcp

Tools for rate limits

4 MCP tools reach this
  • find_rate_limitsBrowse and filter every rate limit in the catalog.
  • apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.
  • resolveTurn a domain, URL or GitHub org into the provider it belongs to.
  • find_cohortsEvery scored population of providers in the catalog.
All 92 tools →

Call it yourself

curl for this page
This rate limit 
curl "https://apis.io/api/v1/rate-limits/litmus-rate-limits"
All rate limits 
curl "https://apis.io/api/v1/rate-limits?limit=25"

Discovery needs no key. Ratings and market analysis are Pro.

Get an API key

Free tier, no form to fill in. Signing in shares your email address with us — we store it to create your key and to recognise you if you sign in with another provider. See our Privacy Policy and Terms.

GitHub Google LinkedIn

A second provider on the same verified email joins the account you already have.