# AttachmentIn

Type: object

Fields typed as another model are documented on that model's page; fetch it before filling the field.

| Field | Type | Required | Description | Allowed values / default / constraints |
| --- | --- | --- | --- | --- |
| `filename` | string | yes | File name the recipient will see, including the extension. |  |
| `content_type` | string | yes | MIME type of the attachment, e.g. `application/pdf`. |  |
| `content_base64` | string | yes | The file's bytes, base64-encoded. All attachments on one message must total no more than 3 MB decoded. |  |

## Used by

- [POST /rest/beta/gmail/send](https://dev-api.sheetgo.com/rest/reference/gmail.md#post-rest-beta-gmail-send)
- [POST /rest/beta/outlook/send](https://dev-api.sheetgo.com/rest/reference/outlook.md#post-rest-beta-outlook-send)
- [GmailSendBody](https://dev-api.sheetgo.com/rest/reference/models/GmailSendBody.md)
- [SendBody](https://dev-api.sheetgo.com/rest/reference/models/SendBody.md)

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More: start page https://dev-api.sheetgo.com/rest/reference.md, everything in one file https://dev-api.sheetgo.com/rest/llms-full.txt, OpenAPI https://dev-api.sheetgo.com/rest/openapi.json.