Guides
Bulk sending
Send multiple email messages with concurrency and batch-aware transports.
The one rule
Use
sendBulk for independent messages; it reports per-message failures instead of throwing the entire batch result away.const result = await mailer.sendBulk(messages, { concurrency: 5, stopOnError: false });Resend and SendGrid can use transport batch support; messages with attachments are sent individually.
Each result entry is either
{ status: "sent", result } or { status: "failed", error }.