Inline vs reusable

7. Inline Blocks vs Reusable Blocks

When to Use

When deciding between non-reusable inline blocks (created within Layout Builder) and reusable block content entities.

Decision

If you need...	Use...	Why
Content unique to this layout placement	Inline block (`inline_block:*`)	Content lives with layout, not reusable, simpler for one-off content
Same content in multiple placements	Reusable block (`block_content:*`)	One block content entity, multiple placements reference it, changes apply everywhere
Content managed outside Layout Builder	Reusable block via Block Library	Separate administration, can be placed via Block Layout or LB
Per-entity custom content in override	Inline block	Created when editing entity override layout, belongs to that entity
Content that should survive layout changes	Reusable block	Inline blocks tied to component UUID, removing from layout = orphaned
Simpler editorial experience	Inline block	Edit content inline when editing layout, no separate interface

Pattern

Inline block:

// Creating inline block component
$component = new SectionComponent(
  \Drupal::service('uuid')->generate(),
  'content',
  [
    'id' => 'inline_block:basic',  // basic = block_content type
    'label' => 'My inline block',
    'view_mode' => 'full',
    'block_serialized' => NULL,    // Set after block created
    'context_mapping' => ['entity' => 'layout_builder.entity'],
  ]
);

Reusable block:

// Reference existing block content entity
$block_content = \Drupal\block_content\Entity\BlockContent::load(123);
$component = new SectionComponent(
  \Drupal::service('uuid')->generate(),
  'content',
  [
    'id' => 'block_content:' . $block_content->uuid(),
    'label_display' => '0',
  ]
);

Reference: /core/modules/layout_builder/src/Plugin/Block/InlineBlock.php for inline block implementation.

Common Mistakes

Using inline for repeated content → Creates duplicate content. Use reusable blocks when same content appears in multiple places
Not cleaning up inline block orphans → Removing inline block from layout leaves orphaned block_content entity. Run cron or use cleanup module
Confusing block_content plugins → inline_block:basic creates new non-reusable block. block_content:{uuid} references existing reusable block. Different plugins
Expecting inline blocks to be portable → Inline blocks tied to specific layout placement via UUID. Can't easily move to different section or entity
Editing inline blocks in Block admin → Inline blocks (reusable = false) don't appear in Block Content admin. Must edit through Layout Builder
Not considering content workflow → Inline blocks follow entity's moderation state. Reusable blocks have own workflow. Choose based on governance needs