New Block Kit layout block

The layout block is now available for Block Kit use.

The layout block arranges other blocks into a grid of rows and side-by-side items, so a single message or view can present structured, multi-column content instead of one vertical stack. Use it for summaries, detail panes, and metric strips, anywhere a column of stacked blocks could waste horizontal space. Other benefits include:

• Denser, more scannable output: put related fields side by side instead of stacking them.
• Composition with blocks you already use: section, image, actions, table, and other blocks drop into a layout item, no changes required.
• Layout hints, not pixel math: declare narrow/standard/wide, and Slack handles the rest.
• Self-contained structure: the grid lives entirely inside one block, so reordering the parent blocks array won't break it.
• Graceful degradation: older clients render your fallback blocks.

For more details about building with Block Kit, check out our Block Kit overview!