---
title: Attachments
description: Attach bytes, strings, or runtime-supported file paths to email.
icon: Paperclip
source: "src/core/types.ts"
---

<Callout title="The one rule">Use `content` for portable attachments; `path` is available only on Node.js and Bun.</Callout>

```ts
await mailer.send({
  from: "hello@example.com", to: "person@example.com", subject: "Invoice",
  attachments: [{ filename: "invoice.txt", content: "Paid" }],
});
```

Attachments can set `contentType`, `encoding`, `contentId`, `inline`, and MIME `headers`.

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