Customer.io · Rate Limits

Customer Io Rate Limits

Customer.io applies per-endpoint rate limits that differ by API surface. The Track (Behavioral Tracking) API has a fair-use limit of 100 requests per second for both live integrations and historical backfill, applying to v1 and v2. On the App API most requests are limited to 10 requests per second, with API-triggered broadcasts limited to 1 request every 10 seconds and transactional messages allowed up to 100 requests per second. The Pipelines / CDP API enforces payload-size limits of 64 KB per single request and 1 MB per batch request.

Customer Io Rate Limits is the rate-limit profile for Customer.io on the APIs.io network — every limit transcribed verbatim from the provider’s own documentation on 2026-10-12.

It captures 4 rate-limit definitions, including Track and Pipelines APIs — 3,000 requests per 3 seconds. This is a soft limit.; App API — 10 requests per second.; Transactional messages — Transactional sends go through the same ingress as the Track and Pipelines APIs and share their soft limit..

Limit state is signalled in the published, request, response, and retry_after response headers, and an exhausted limit returns HTTP 429.

The profile also includes 2 backoff/retry policies defined and response codes documented for throttled.

Tagged areas include Customer Messaging, Marketing Automation, Email, CDP, and Transactional.

4 Limits Exhausted: HTTP 429 publishedrequestresponseretry_after
Transcribed from the provider's documentation on 2026-10-12 — docs.customer.io/integrations/api/customerio-apis.md.
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Customer MessagingMarketing AutomationEmailCDPTransactionalRate LimitingQuotasThrottling

Limits

Track and Pipelines APIs account
3,000 requests per 3 seconds. This is a soft limit.
· per 3 seconds
Not strictly enforced; exceeding it does not return a 429.
App API account
10 requests per second.
· per 1 second
10
Transactional messages account
Transactional sends go through the same ingress as the Track and Pipelines APIs and share their soft limit.
/integrations/api/app/tag/send-messages/
· per 3 seconds
API-triggered broadcasts account
1 request every 10 seconds.
triggerBroadcast
· per 10 seconds

Policies

Per-Endpoint Limits
Limits are enforced per endpoint category rather than a single global account limit.
Backoff Strategy
Clients should implement exponential backoff with jitter and honor Retry-After on HTTP 429 responses.

Sources

Work with this as data

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

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Tools for rate limits

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  • 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.
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All rate limits 
curl "https://apis.io/api/v1/rate-limits?limit=25"

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