---
title: Bulk sending
description: Send multiple email messages with concurrency and batch-aware transports.
icon: Layers
source: "src/mailer.ts"
---

<Callout title="The one rule">Use `sendBulk` for independent messages; it reports per-message failures instead of throwing the entire batch result away.</Callout>

```ts
const result = await mailer.sendBulk(messages, { concurrency: 5, stopOnError: false });
```

Resend and SendGrid can use transport batch support; messages with attachments are sent individually.

<Accordions><Accordion title="How are errors represented?">Each result entry is either `{ status: "sent", result }` or `{ status: "failed", error }`.</Accordion></Accordions>

<Cards><Card title="Mail options" href="/docs/reference/mail-options" /></Cards>