There are several rate limitations and restrictions that you should be aware of when using the v3 Mail Send endpoint.
- The total size of your email, including attachments, must be less than 30MB.
- The total number of recipients must no more than 1000. This includes all recipients defined within the
bccparameters, across each object that you include in the
- The total length of custom arguments must be less than 10000 bytes.
- Unicode encoding is not supported for the
bcc.namepersonalizations cannot include either the
For more specific, parameter level requirements and limitations, please refer to the v3/mail/send documentation.