Interface: MessageAttachment
Add secondary attachments to your messages in Slack. Message attachments are considered a legacy part of messaging functionality. They are not deprecated per se, but they may change in the future, in ways that reduce their visibility or utility. We recommend moving to Block Kit instead. Read more about when to use message attachments.
See
Secondary message attachments reference documentation
Properties
actions?
optional actions: AttachmentAction[];
Defined in
app_id?
optional app_id: string;
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app_unfurl_url?
optional app_unfurl_url: string;
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author_icon?
optional author_icon: string;
Description
A valid URL that displays a small 16px by 16px image to the left of the author_name text.
Will only work if author_name is present.
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author_link?
optional author_link: string;
Description
A valid URL that will hyperlink the author_name text. Will only work if author_name is present.
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author_name?
optional author_name: string;
Description
Small text used to display the author's name.
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author_subname?
optional author_subname: string;
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blocks?
optional blocks: AnyBlock[];
Description
An array of layout blocks in the same format as described in the building blocks guide.
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bot_id?
optional bot_id: string;
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callback_id?
optional callback_id: string;
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color?
optional color: string;
Description
Changes the color of the border on the left side of this attachment from the default gray. Can either
be one of good (green), warning (yellow), danger (red), or any hex color code (eg. #439FE0)
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fallback?
optional fallback: string;
Description
A plain text summary of the attachment used in clients that don't show formatted text (e.g. mobile notifications).
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fields?
optional fields: MessageAttachmentField[];
Description
An array of MessageAttachmentField that get displayed in a table-like way (see this example). For best results, include no more than 2-3 field objects.
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footer?
optional footer: string;
Description
Some brief text to help contextualize and identify an attachment. Limited to 300 characters, and may be truncated further when displayed to users in environments with limited screen real estate.
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footer_icon?
optional footer_icon: string;
Description
A valid URL to an image file that will be displayed beside the footer text.
Will only work if footer is present. We'll render what you provide at 16px by 16px.
It's best to use an image that is similarly sized.
Defined in
image_url?
optional image_url: string;
Description
A valid URL to an image file that will be displayed at the bottom of the attachment.
We support GIF, JPEG, PNG, and BMP formats.
Large images will be resized to a maximum width of 360px or a maximum height of 500px, while still
maintaining the original aspect ratio. Cannot be used with thumb_url.
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is_app_unfurl?
optional is_app_unfurl: boolean;
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mrkdwn_in?
optional mrkdwn_in: ("text" | "pretext" | "fields")[];
Description
Field names that should be formatted by mrkdwn syntax.
The fields that can be formatted in this way include the names of the fields property, or
the text or pretext properties.
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pretext?
optional pretext: string;
Description
Text that appears above the message attachment block. It can be formatted as plain text,
or with mrkdwn by including it in the mrkdwn_in field.
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preview?
optional preview: MessageAttachmentPreview;
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text?
optional text: string;
Description
The main body text of the attachment. It can be formatted as plain text, or with
mrkdwn by including it in the mrkdwn_in field.
The content will automatically collapse if it contains 700+ characters or 5+ line breaks, and will display
a "Show more..." link to expand the content.
Defined in
thumb_url?
optional thumb_url: string;
Description
A valid URL to an image file that will be displayed as a thumbnail on the right side of a message attachment. We currently support the following formats: GIF, JPEG, PNG, and BMP. The thumbnail's longest dimension will be scaled down to 75px while maintaining the aspect ratio of the image. The file size of the image must also be less than 500 KB. For best results, please use images that are already 75px by 75px.
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title?
optional title: string;
Description
Large title text near the top of the attachment.
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title_link?
optional title_link: string;
Description
A valid URL that turns the title text into a hyperlink.
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ts?
optional ts: string;
Description
A Unix timestamp that is used to relate your attachment to a specific time. The attachment will display the additional timestamp value as part of the attachment's footer. Your message's timestamp will be displayed in varying ways, depending on how far in the past or future it is, relative to the present. Form factors, like mobile versus desktop may also transform its rendered appearance.