Blocks and elements

Every block and element type in @slack/types 3.0.0 renders, as do the newer message-surface blocks Slack has documented but not yet typed (container, data_table, and data_visualization). Anything outside that inventory still renders as a visible, labeled fallback (see Unknown blocks and fallbacks).

Blocks

Block type	Notes
`section`	Text, up to 10 `fields`, and any accessory; unknown accessories fall back visibly
`rich_text`	Full container and inline inventory; see below
`header`	Semantic `h1`–`h4` via the `level` field; out-of-range levels clamp
`context`	Text and image elements
`divider`	—
`image`	URL images render; `slack_file` IDs render an alt-labeled placeholder (a file ID has no fetchable URL)
`actions`	All interactive elements below
`input`	Labels, hints, and all input elements below
`markdown`	Minimal Markdown subset: headings, paragraphs, quotes, lists (including task lists), fenced code, tables, dividers, inline emphasis
`table`	`raw_text`, `raw_number`, and `rich_text` cells; column alignment and wrapping; first row renders with column-header semantics
`data_table`	Caption, header/row semantics, pagination; renders safely with empty rows
`data_visualization`	`pie`, `bar`, `line`, and `area` charts with legends; a zero-total pie renders a labeled no-data state
`container`	Legal Slack child blocks, collapsible state, header/subtitle/icon
`card`	Title, subtitle, body, hero image, icon, actions
`carousel`	Card elements
`alert`	Info/warning/error/success levels (modal surface in Slack)
`context_actions`	—
`file`	—
`plan`	Title and task cards
`task_card`	—
`video`	—

The newer message blocks

Slack's recent additions are the ones most likely to decide whether this renderer covers what you need, and they are hard to picture from a table row. card and carousel:

Release 2.41.0

Shipped to production

32 checks passed. Rollout took 4m 12s.

Triggered from main

us-east-1

412 errors, p95 188 ms

eu-west-1

17 errors, p95 176 ms

View payload JSON

{
  "blocks": [
    {
      "type": "card",
      "slack_icon": {
        "type": "icon",
        "name": "rocket"
      },
      "title": {
        "type": "plain_text",
        "text": "Release 2.41.0"
      },
      "subtitle": {
        "type": "plain_text",
        "text": "Shipped to production"
      },
      "body": {
        "type": "mrkdwn",
        "text": "32 checks passed. Rollout took *4m 12s*."
      },
      "subtext": {
        "type": "plain_text",
        "text": "Triggered from main"
      },
      "actions": [
        {
          "type": "button",
          "action_id": "open_run",
          "text": {
            "type": "plain_text",
            "text": "Open run"
          }
        }
      ]
    },
    {
      "type": "carousel",
      "elements": [
        {
          "type": "card",
          "title": {
            "type": "plain_text",
            "text": "us-east-1"
          },
          "body": {
            "type": "plain_text",
            "text": "412 errors, p95 188 ms"
          }
        },
        {
          "type": "card",
          "title": {
            "type": "plain_text",
            "text": "eu-west-1"
          },
          "body": {
            "type": "plain_text",
            "text": "17 errors, p95 176 ms"
          }
        }
      ]
    }
  ]
}

A collapsible container, a paginated data_table, and a bar chart:

Deployment

Production

Version: 2.41.0

Error budget by region

Error budget by region
Region	Errors
us-east-1	412
eu-west-1	17
ap-south-1	233
eu-central-1	88
us-west-2	51

Weekly output

Tasks

Completed

View payload JSON

{
  "blocks": [
    {
      "type": "container",
      "title": {
        "type": "plain_text",
        "text": "Deployment"
      },
      "subtitle": {
        "type": "plain_text",
        "text": "Production"
      },
      "is_collapsible": true,
      "has_header_divider": true,
      "child_blocks": [
        {
          "type": "section",
          "text": {
            "type": "mrkdwn",
            "text": "*Version:* 2.41.0"
          }
        },
        {
          "type": "divider"
        },
        {
          "type": "actions",
          "elements": [
            {
              "type": "button",
              "action_id": "view_logs",
              "text": {
                "type": "plain_text",
                "text": "View logs"
              }
            }
          ]
        }
      ]
    },
    {
      "type": "data_table",
      "caption": "Error budget by region",
      "page_size": 5,
      "row_header_column_index": 0,
      "rows": [
        [
          {
            "type": "raw_text",
            "text": "Region"
          },
          {
            "type": "raw_text",
            "text": "Errors"
          }
        ],
        [
          {
            "type": "raw_text",
            "text": "us-east-1"
          },
          {
            "type": "raw_number",
            "value": 412,
            "text": "412"
          }
        ],
        [
          {
            "type": "raw_text",
            "text": "eu-west-1"
          },
          {
            "type": "raw_number",
            "value": 17,
            "text": "17"
          }
        ],
        [
          {
            "type": "raw_text",
            "text": "ap-south-1"
          },
          {
            "type": "raw_number",
            "value": 233,
            "text": "233"
          }
        ],
        [
          {
            "type": "raw_text",
            "text": "eu-central-1"
          },
          {
            "type": "raw_number",
            "value": 88,
            "text": "88"
          }
        ],
        [
          {
            "type": "raw_text",
            "text": "us-west-2"
          },
          {
            "type": "raw_number",
            "value": 51,
            "text": "51"
          }
        ],
        [
          {
            "type": "raw_text",
            "text": "sa-east-1"
          },
          {
            "type": "raw_number",
            "value": 9,
            "text": "9"
          }
        ]
      ]
    },
    {
      "type": "data_visualization",
      "title": "Weekly output",
      "chart": {
        "type": "bar",
        "axis_config": {
          "categories": [
            "Mon",
            "Tue",
            "Wed"
          ],
          "y_label": "Tasks"
        },
        "series": [
          {
            "name": "Completed",
            "data": [
              {
                "label": "Mon",
                "value": 8
              },
              {
                "label": "Tue",
                "value": 12
              },
              {
                "label": "Wed",
                "value": 10
              }
            ]
          }
        ]
      }
    }
  ]
}

alert is a modal block, so it renders here on the modal surface:

Canary is live.

Retries elevated in us-east-1.

Rollout halted at 40%.

All regions healthy.

View payload JSON

{
  "blocks": [
    {
      "type": "alert",
      "level": "info",
      "text": {
        "type": "plain_text",
        "text": "Canary is live."
      }
    },
    {
      "type": "alert",
      "level": "warning",
      "text": {
        "type": "plain_text",
        "text": "Retries elevated in us-east-1."
      }
    },
    {
      "type": "alert",
      "level": "error",
      "text": {
        "type": "plain_text",
        "text": "Rollout halted at 40%."
      }
    },
    {
      "type": "alert",
      "level": "success",
      "text": {
        "type": "plain_text",
        "text": "All regions healthy."
      }
    }
  ]
}

Rich text

Containers: rich_text_section, rich_text_list (real ul/ol with ordered offset, per-depth markers, indent bounded to 0–8), rich_text_quote (payload border honored), and rich_text_preformatted (language and border honored).

Inline elements: text with deterministically nested bold / italic / strike / code styling, link (protocol-checked), emoji, user, channel, usergroup, team, broadcast, date, color (swatch and value), and compact textual fallbacks for citation and Slack's internal reference mentions (canvas, file, workflow, and similar). Unknown inline types render a visible fallback.

Interactive elements

Group	Types
Buttons	`button` (default, `primary`, `danger`; URL buttons render as links)
Selects	`static_select`, `external_select`, `users_select`, `channels_select`, `conversations_select`, and their `multi_*` variants
Menus	`overflow` (Slack's ellipsis button; the menu does not open and `options` are not displayed)
Choices	`checkboxes`, `radio_buttons`
Inputs	`plain_text_input`, `email_text_input`, `url_text_input`, `number_input`, `datepicker`, `timepicker`, `datetimepicker`, `file_input`, `rich_text_input`
Workflow	`workflow_button` (renders as a button; does not emit `onAction`)
Context actions	`icon_button`, `feedback_buttons` (inside `context_actions`)
Images	`image` (element and accessory)

Apart from workflow_button and image, all of these report through onAction when they carry an action_id. See Handling actions.

Mrkdwn formatting

Mrkdwn text (section text, fields, context elements) supports:

Syntax	Rendering
`bold`, `_italic_`, `~strike~`	Semantic `strong`/`em`/`s`, nesting allowed
`code` and ``` fenced blocks	Inline code and preformatted blocks
`<https://…\|label>`	Protocol-checked links; bare `http(s)`/`mailto` URLs auto-link
`<@U…>`, `<#C…>`, `<!subteam^S…>`	Mentions, with resolver and payload-label fallbacks
`<!here>`, `<!channel>`, `<!everyone>`	Broadcast mentions
`<!date^ts^{token}\|fallback>`	Deterministic UTC date formatting; fallback for relative tokens
`:shortcode:`	Emoji: 36 built-in glyphs, literal `:name:` for every other shortcode
`&` `<` `>`	Decoded everywhere, including links, labels, and code

Emoji shortcodes require token boundaries, so times and ratios like 12:30:45 stay literal text.

The exact TypeScript shape of every block and element is on Exported types.