Chat SDK Attachments - Resend

When someone sends an email with file attachments, the adapter makes them available on message.raw.attachments. Each attachment includes the filename, MIME type, and a URL to download the content.

Attachment shape

interface ResendAttachment {
  filename: string;
  contentType: string;
  url?: string;
}

Field	Type	Description
`filename`	`string`	Original filename (e.g., `invoice.pdf`)
`contentType`	`string`	MIME type (e.g., `application/pdf`)
`url`	`string`	Optional download URL for the attachment content

Detecting and processing attachments

chat.onNewMention(async (thread, message) => {
  const attachments = message.raw?.attachments ?? [];

  if (attachments.length === 0) {
    await thread.subscribe();
    await thread.post('Got your email — no attachments found.');
    return;
  }

  const summary = attachments
    .map((a) => `${a.filename} (${a.contentType})`)
    .join(', ');

  await thread.subscribe();
  await thread.post(`Received ${attachments.length} attachment(s): ${summary}`);
});

For more on receiving email attachments outside the Chat SDK, see Receiving Attachments.

Try it yourself

Attachments Example

Detects attachments and replies with a summary

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