Send Messages

Use these endpoints to send broadcasts or transactional messages to your audience. They use the same authentication method, but review the limits for both types of workflows to make sure you'll successfully trigger your messages.

You can't trigger campaigns through our APIs.

API triggered broadcast limits

While API triggered broadcasts are limited to 1 request every 10 seconds, they're also limited by the number of triggers you can have queued at a time, as shown in the table below.

Data Type	Limit	Description
Trigger Payload	25MB	Max length of the entire Trigger call, larger calls are typically to support per_user_data
Trigger Data	50000 bytes	Max length of the data section in the Trigger call
Recipient List1	10000 recipients	Max number of ids or emails included in the Trigger call
Custom Per User Data1	10000 entries	Max number of entries in per_user_data
Custom Per User Data1	2MB	Max length per user in the file referenced by data_file_url.
Custom Per User Data1	10GB	Max length of the entire size of the file referenced by data_file_url
Trigger Queue	5 triggers	Max number of triggers waiting to be processed consecutively

¹For larger data sets, use data_file_url to supply a link to a file that contains your merge data. Attempting to send too much data in a single API call will fail.

Transactional Message Limits

The /send-* endpoints are limited to 100 requests per second.

Data Type	Limit	Description
Payload	1MB	Max length of the payload, excepting attachments
Attachments (email)	2MB	Maximum size of attachments
Recipients	15	Total number of recipients across the to, cc, and bcc fields.