batch_handling
Since: Dev Builds Only
The functionality described in this section requires a dev build of KumoMTA. You can obtain a dev build by following the instructions in the Installation section.
SMTP messages can have an envelope that includes multiple recipients. Each recipient will receive a copy of the message. If multiple recipients share the same mailbox provider then it is advantageous from a bandwidth and efficiency perspective to relay that message to that provider as a single message with a list of multiple recipients, rather than sending one distinct copy per recipient.
The batch_handling
option specifies how incoming multi-recipient transactions
are split into outgoing batches.
It can have one of two values:
"BifurcateAlways"
- this is the default and recommended setting for sender-focused deployments. Every incoming recipient is placed into a separate batch and tracked separately."BatchByDomain"
- recipients with exactly the same domain portion are grouped together, resulting in one outgoing batch per unique domain.
If you have more advanced requirements around managing batching/splitting, then you can implement them via the smtp_server_split_transaction event handler.