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Welcome to the new home of Slack developer docs!

We're still building and not all features are available quite yet. Enjoy this peek into the future!

Not ready for the future? Return to the past at api.slack.com.

Fields

Field	Type	Description	Required?
type	String	The type of block. For this block, type will always be header.	Required
text	Object	The text for the block, in the form of a plain_text text object. Maximum length for the text in this field is 150 characters.	Required
block_id	String	A unique identifier for a block. If not specified, one will be generated. Maximum length for this field is 255 characters. block_id should be unique for each message and each iteration of a message. If a message is updated, use a new block_id.	Optional

Usage info

A header is a plain-text block that displays in a larger, bold font. Use it to delineate between different groups of content in your app's surfaces.

Example

{
  "type": "header",
  "text": {
    "type": "plain_text",
    "text": "A Heartfelt Header"
  }
}