Lists
Add bulk subscribers
Subscribe multiple contacts to a specific list in a single request.
POST
ID of the list.
Array of subscriber objects. Limited to 3000 subscribers per call — subscribers above the limit are ignored.
Update subscribers that already exist in the list.
Force resubscribe if the subscriber was previously unsubscribed.
Trigger automations when subscribers are added.
Subscribers added via bulk subscribe always skip double opt-in confirmation. Custom fields are limited to 5000 characters total. Custom field keys are case-insensitive — they are trimmed and lowercased on input, so
SHOP, shop and Shop are treated as the same field; two keys that differ only in case or whitespace within the same subscriber are rejected as duplicates. Tags are limited to 2000 characters total and 50 characters per tag — tag content only updates when the tags parameter is present and update_existing is true.