Container block
Groups child blocks under a title, optionally collapsible, with a configurable width.
| Type | container |
| Available in | Messages, Modals, Home tab |
Fields
Section titled “Fields”| Field | Type | Description | Required? |
|---|---|---|---|
type |
String | The type of block. For a container block, type is always container. |
Required |
title |
Text object | Title of the container, using plain_text. Maximum 150 characters. |
Required if rich_text_title is missing |
rich_text_title |
Rich text block | The title as a rich_text block. Takes precedence over title when both are present. |
Required if title is missing |
subtitle |
Text object | Subtitle, plain_text or mrkdwn. Maximum 150 characters. |
Optional |
child_blocks |
Object[] | The blocks inside the container. Maximum 10 blocks. | Required |
block_id |
String | A unique identifier for the block. Maximum length is 255 characters. It must be unique within the message or view — a duplicate is replaced and reported as a warning. | Optional |
width |
String | One of narrow, standard, wide or full. full fills the available space. Defaults to standard. |
Optional |
icon |
Image element | A small image shown next to the title. image_url is at most 3000 characters, alt_text at most 2000. |
Optional |
is_collapsible |
Boolean | When true, readers can collapse the container to its title. Defaults to false. |
Optional |
default_collapsed |
Boolean | When true and is_collapsible is true, the container starts collapsed. Defaults to false. |
Optional |
has_header_divider |
Boolean | When true, a line separates the title from the content. Only applies when the container isn’t collapsible. Defaults to false. |
Optional |
Examples
Section titled “Examples”A container with a header divider
Section titled “A container with a header divider”
{ "blocks": [ { "type": "container", "title": { "type": "plain_text", "text": "Order SO-2041 — 3 lines on backorder" }, "subtitle": { "type": "mrkdwn", "text": "Customer: *Gulf Retail Co.*" }, "has_header_divider": true, "child_blocks": [ { "type": "section", "text": { "type": "mrkdwn", "text": "*LT-1400* ProBook 14 × 10 — ships 24 Oct\n*PRN-80* Receipt printer × 10 — ships 28 Oct\n*CD-58* Cash drawer × 10 — ships 2 Nov" } }, { "type": "actions", "elements": [ { "type": "button", "action_id": "split_shipment", "text": { "type": "plain_text", "text": "Ship available items" }, "style": "primary", "value": "SO-2041" }, { "type": "button", "action_id": "notify_customer", "text": { "type": "plain_text", "text": "Notify customer" }, "value": "SO-2041" } ] } ] } ]}A collapsed container with a rich text title
Section titled “A collapsed container with a rich text title”
{ "blocks": [ { "type": "container", "width": "wide", "is_collapsible": true, "default_collapsed": true, "rich_text_title": { "type": "rich_text", "elements": [ { "type": "rich_text_section", "elements": [ { "type": "text", "text": "Audit details for ticket #4821" } ] } ] }, "child_blocks": [ { "type": "section", "fields": [ { "type": "mrkdwn", "text": "*Opened*\n12 Oct, 09:14" }, { "type": "mrkdwn", "text": "*First reply*\n12 Oct, 09:31" }, { "type": "mrkdwn", "text": "*Reassigned*\n2 times" }, { "type": "mrkdwn", "text": "*SLA*\nMet" } ] }, { "type": "context", "elements": [ { "type": "mrkdwn", "text": "Generated by the Helpdesk app" } ] } ] } ]}