# Receiving attachments

> Bytes on webhook, message show, and a download URL.

Files on inbound mail are available in the dashboard, on the API, and on the webhook. Where you get the bytes depends on the channel.

## Where the bytes are

| Channel | What you get |
| --- | --- |
| Message list (`GET …/inbound_messages`) | Metadata only: `filename`, `content_type`, `size` |
| Message show (`GET …/inbound_messages/:id`) | Metadata plus `content_base64` |
| JSON webhook | Metadata plus `content_base64` |
| Download URL (`GET …/attachments/:index`) | The raw file |
| Dashboard | **Download** on each attachment in the message view |

Attachments are numbered from `1`, in the order they appear in the message.

PostShiba keeps the same file types it lets you send: images (including SVG and HEIC), PDF, Office and OpenDocument files, RTF, plain text, CSV, zip archives, contact cards, and calendar invites. Other files, such as programs, scripts, and HTML pages, are left out. Mail carrying a virus is refused before it reaches your inbox.

With retention off, bytes are removed from every channel once the webhook delivers: the show's `content_base64` is `null`, the API download returns `410`, and the dashboard shows the file name without a download link. Without a webhook, the bytes stay for 7 days. See [Retention and storage](/docs/dashboard/receiving/introduction#retention-and-storage).

## Attachment fields

```json attachment.json
{
  "filename": "photo.png",
  "content_type": "image/png",
  "size": 70,
  "content_base64": "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg=="
}
```

## SendGrid Inbound Parse format

A `sendgrid_parse` webhook sends files as form fields `attachment1`, `attachment2`, and so on. `attachment-info` is JSON with each file's name and type. The `email` field holds the raw MIME.

Download steps are on [Managing received emails](/docs/dashboard/receiving/manage-emails). Full fields are on [Inbound messages](/docs/api-reference/messages).

## Next steps

- [Managing received emails](/docs/dashboard/receiving/manage-emails)
- [Get email content](/docs/dashboard/receiving/get-email-content)
- [Receiving webhooks](/docs/dashboard/receiving/create-receiving-webhook)
- [Inbound messages API](/docs/api-reference/messages)