Reference: block_actions payloads

A block_actions payload is received when a user interacts with a Block Kit interactive component.

Read our guide to handling payloads from user interactions to learn how your app should process and respond to these payloads.

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Timing of payload dispatch

Different interactive components will cause an interaction payload to be sent at different moments:

Component	Payload sent
button	When the button is clicked.
checkboxes	When a checkbox is ticked or unticked.
datepicker	When a date is chosen and the date picker closes.
multi_*_select	Each time an item is chosen from the multi-select menu.
overflow	When an item from the overflow menu is clicked.
plain_text_input	Determined by the dispatch_action_config field in the element.
radio	When the selected radio in a group of radio buttons is changed.
*_select	When an item is chosen from the select menu.

Fields

This is a non-exhaustive list of fields that can be encountered in this type of interaction payload:

Field	Description
type	Helps identify which type of interactive component sent the payload; An interactive element in a block will have a type of block_actions, whereas an interactive element in a message attachment will have a type of interactive_message.
trigger_id	A short-lived ID that can be used to open modals.
response_url	A short-lived webhook that can be used to send messages in response to interactions.
user	The user who interacted to trigger this request.
message or view	The source app surface the user initiated the interaction from. This will include the full state of the message, or the view within a modal or Home tab. If the source was an ephemeral message, this field will not be included.
actions	Contains data from the specific interactive component that was used. App surfaces can contain blocks with multiple interactive components, and each of those components can have multiple values selected by users. Combine the fields within actions (shown below) to help provide the full context of the interaction.
actions.block_id	Identifies the block within a surface that contained the interactive component that was used. See the reference guide for the block you're using for more info on the block_id field.
actions.action_id	Identifies the interactive component itself. Some blocks can contain multiple interactive components, so the block_id alone may not be specific enough to identify the source component. See the reference guide for the interactive element you're using for more info on the action_id field.
actions.value	Set by your app when you composed the blocks, this is the value that was specified in the interactive component when an interaction happened. For example, a select menu will have multiple possible values depending on what the user picks from the menu, and value will identify the chosen option. See the reference guide for the interactive element you're using for more info on the value field.
token	Represents a deprecated verification token feature. You should validate the request payload, however, and the best way to do so is to use the signing secret provided to your app.
hash	A unique value which is optionally accepted in views.update and views.publish API calls. When provided to those APIs, the hash is validated such that only the most recent view can be updated. This should be used to ensure the correct view is being updated when updates are happening asynchronously.
state.values or view.state.values	A dictionary of objects keyed with the block_ids of all blocks containing stateful, interactive components . Within each block_id object is another object keyed by the action_id of the child block element. This final child object will contain the type and value of the action block element. If the call originates from a Home tab or modal view it will be in view.state.values and if it originates from a message it will be in state.values.

The remainder of the payload will identify the source of the interaction, giving your app info such as the channel the source interaction happened in, and the workspace (team) that channel is in.

Examples

A payload from an interactive component used in a message:

{
  "type": "block_actions",
  "team": {
    "id": "T9TK3CUKW",
    "domain": "example"
  },
  "user": {
    "id": "UA8RXUSPL",
    "username": "jtorrance",
    "team_id": "T9TK3CUKW"
  },
  "api_app_id": "AABA1ABCD",
  "token": "9s8d9as89d8as9d8as989",
  "container": {
    "type": "message_attachment",
    "message_ts": "1548261231.000200",
    "attachment_id": 1,
    "channel_id": "CBR2V3XEX",
    "is_ephemeral": false,
    "is_app_unfurl": false
  },
  "trigger_id": "12321423423.333649436676.d8c1bb837935619ccad0f624c448ffb3",
  "channel": {
    "id": "CBR2V3XEX",
    "name": "review-updates"
  },
  "message": {
    "bot_id": "BAH5CA16Z",
    "type": "message",
    "text": "This content can't be displayed.",
    "user": "UAJ2RU415",
    "ts": "1548261231.000200",
    ...
  },
  "response_url": "https://hooks.slack.com/actions/AABA1ABCD/1232321423432/D09sSasdasdAS9091209",
  "actions": [
    {
      "action_id": "WaXA",
      "block_id": "=qXel",
      "text": {
        "type": "plain_text",
        "text": "View",
        "emoji": true
      },
      "value": "click_me_123",
      "type": "button",
      "action_ts": "1548426417.840180"
    }
  ]
}

A payload from an interactive component used in a Home tab:

{
    "type":"block_actions",
    "team":{
        "id": "T9TK3CUKW",
        "domain": "example"
    },
    "user":{
        "id": "UA8RXUSPL",
        "username": "jtorrance",
        "name": "jtorrance",
        "team_id": "T9TK3CUKW"
    },
    "api_app_id":"AABA1ABCD",
    "token":"9s8d9as89d8as9d8as989",
    "container":{
        "type":"view",
        "view_id":"V0PKB1ZFV"
    },
    "trigger_id":"24571818370.22717085937.b9c7ca14b87be6b44ff5864edba8306f",
    "view":{
      "id":"V0PKB1ZFV",
      "team_id":"T9TK3CUKW",
      "type":"home",
      "blocks":[
          {
            "type":"section",
            "block_id":"8ZG",
            "text":{
                "type":"mrkdwn",
                "text":"A stack of blocks for the simple sample Block Kit Home tab.",
                "verbatim":false
            }
          },
          {
            "type":"actions",
            "block_id":"7fhg",
            "elements":[
                {
                  "type":"button",
                  "action_id":"XRX",
                  "text":{
                      "type":"plain_text",
                      "text":"Action A",
                      "emoji":true
                  }
                },
                {
                  "type":"button",
                  "action_id":"GFBew",
                  "text":{
                      "type":"plain_text",
                      "text":"Action B",
                      "emoji":true
                  }
                }
            ]
          },
          {
            "type":"section",
            "block_id":"6evU",
            "text":{
                "type":"mrkdwn",
                "text":"And now it's slightly more complex.",
                "verbatim":false
            }
          }
      ],
      "private_metadata":"",
      "callback_id":"",
      "state":{
          "values":{}
      },
      "hash":"1571318366.2468e46f",
      "clear_on_close":false,
      "notify_on_close":false,
      "close":null,
      "submit":null,
      "previous_view_id":null,
      "root_view_id":"V0PKB1ZFV",
      "app_id":"AABA1ABCD",
      "external_id":"",
      "app_installed_team_id":"T9TK3CUKW",
      "bot_id":"B0B00B00"
    },
    "actions":[
      {
          "type":"button",
          "block_id":"7fhg",
          "action_id":"XRX",
          "text":{
            "type":"plain_text",
            "text":"Action A",
            "emoji":true
          },
          "action_ts":"1571318425.267782"
      }
    ]
}