Migrate to Polaris

Version 2025-07 is the last API version to support React-based UI components. Later versions use web components, native UI elements with built-in accessibility, better performance, and consistent styling with Shopify's design system. Check out the migration guide to upgrade your extension.

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BlockLayout

The BlockLayout component arranges content over multiple rows with explicit control over row sizing. Use BlockLayout to create vertical layouts where each row can have a different proportion, such as a fixed header row with an expandable content area below.

BlockLayout supports flexible row configurations and gap spacing for precise vertical layout control. For simpler vertical stacking with uniform spacing, use BlockStack. For horizontal column layouts, use InlineLayout.

Support

Targets (25)

Supported targets

Anchor to PropertiesProperties

Configure the following properties on the BlockLayout component.

Anchor to accessibilityLabel accessibilityLabel string: A label announced by assistive technologies that describes the purpose or contents of the element. Only set this when the element's visible content doesn't provide enough context on its own.
Anchor to accessibilityRole accessibilityRole: The semantic meaning of the component's content. When set, assistive technologies use this role to help users navigate the page. Accepts a single role or a tuple of two roles (for example, ['listItem', 'separator']).
Anchor to background background <> Default: 'transparent': The background color of the element, set using a design-system keyword.
Anchor to blockAlignment blockAlignment <>: The alignment of children along the block (cross) axis.
Anchor to border border <<>>: The border style of the element. Accepts a single value for all four edges, or a shorthand tuple for per-edge control:

'base': Applies base to all edges.

['base', 'none']: Block edges get base, inline edges get none.

['base', 'none', 'dotted', 'base']: Values apply to block-start, inline-end, block-end, and inline-start respectively.
Anchor to borderWidth borderWidth < <> >: The border width of the element. Accepts a single value for all four edges, or a shorthand tuple for per-edge control:

'base': Applies base to all edges.

['base', 'medium']: Block edges get base, inline edges get medium.

['base', 'medium', 'medium', 'base']: Values apply to block-start, inline-end, block-end, and inline-start respectively.
Anchor to cornerRadius cornerRadius < <> >: The corner radius of the element. Accepts a single value for all four corners, or a shorthand tuple for per-corner control using logical (writing-mode-aware) corners:

'base': All four corners get base radius.

['base', 'none']: StartStart/EndEnd get base, StartEnd/EndStart get none. In left-to-right mode, StartStart and EndEnd are the top-left and bottom-right corners.

['base', 'none', 'small', 'base']: Values apply to StartStart, StartEnd, EndEnd, and EndStart respectively.

A borderRadius alias is available. When both are set, cornerRadius takes precedence.
Anchor to display display <'auto' | 'none'> Default: 'auto': The display mode of the component. Learn more about display.

auto: The initial value; the actual behavior depends on the component and context.

none: Hides the component and removes it from the accessibility tree.
Anchor to id id string: A unique identifier for the component. Use this to target the component in scripts or stylesheets, or to distinguish it from other instances of the same component.
Anchor to inlineAlignment inlineAlignment <>: The alignment of children along the inline (main) axis.
Anchor to maxBlockSize maxBlockSize < number | `${number}%` | 'fill' >: The maximum block size (maximum height in horizontal writing modes). The element won't grow taller than this value even if its content is longer.

number: The size in pixels.

`${number}%`: The size as a percentage of the parent container's block size.

'fill': Takes all the available space.

Learn more about the max-block-size property.
Anchor to maxInlineSize maxInlineSize < number | `${number}%` | 'fill' >: The maximum inline size (maximum width in horizontal writing modes). The element won't grow wider than this value.

number: The size in pixels.

`${number}%`: The size as a percentage of the parent container's inline size.

'fill': Takes all the available space.

Learn more about the max-inline-size property.
Anchor to minBlockSize minBlockSize < number | `${number}%` | 'fill' >: The minimum block size (minimum height in horizontal writing modes). The element won't shrink smaller than this value even if its content is shorter.

number: The size in pixels.

`${number}%`: The size as a percentage of the parent container's block size.

'fill': Takes all the available space.

Learn more about the min-block-size property.
Anchor to minInlineSize minInlineSize < number | `${number}%` | 'fill' >: The minimum inline size (minimum width in horizontal writing modes). The element won't shrink narrower than this value.

number: The size in pixels.

`${number}%`: The size as a percentage of the parent container's inline size.

'fill': Takes all the available space.

Learn more about the min-inline-size property.
Anchor to overflow overflow 'hidden' | 'visible' Default: 'visible': The overflow behavior of the element.

visible: Content that extends beyond the container is visible.

hidden: Content that extends beyond the container is clipped and not scrollable.
Anchor to padding padding <<>>: The padding on all edges of the element, using a shorthand syntax. You can specify one, two, or four values following the CSS shorthand convention.

T: A single value applied uniformly to all edges.

[T, T]: The first value applies to block-start and block-end, the second to inline-start and inline-end.

[T, T, T, T]: Values apply to block-start, inline-end, block-end, and inline-start respectively.
Anchor to rows rows <> Default: 'fill': The sizes for each row of the layout.

auto: The intrinsic size of the element.

fill: Fills the remaining available space. When multiple elements use fill, the space is shared equally.

`${number}%`: A percentage of the container's block size.

`${number}fr`: A fractional unit of the available space.

number: A fixed size in pixels.

When the sum of defined sizes exceeds the available space, elements shrink to avoid overflow. Elements without an explicit size fill the remaining space. A single value outside an array applies to all rows.
Anchor to spacing spacing < | [, ]> Default: 'none': The spacing between child elements. A single value applies to both the row and column axes. A pair of values (for example, ['base', 'none']) sets the row and column spacing independently.
Anchor to borderRadius borderRadius < <> >: The corner radius of the element. Accepts a single value for all four corners, or a shorthand tuple for per-corner control:

'base': All four corners get base radius.

['base', 'none']: StartStart/EndEnd get base, StartEnd/EndStart get none.

['base', 'none', 'small', 'base']: Values apply to StartStart, StartEnd, EndEnd, and EndStart respectively.

Deprecated
Use cornerRadius instead.

ViewLikeAccessibilityRole

The accessibility role accepted by view-like layout components. Accepts a single `NonPresentationalAccessibilityRole`, or a tuple of two roles to combine semantic meaning (for example, `['listItem', 'separator']` renders as `<li role='separator'>`).

NonPresentationalAccessibilityRole | [NonPresentationalAccessibilityRole, NonPresentationalAccessibilityRole]

NonPresentationalAccessibilityRole

The subset of accessibility roles available to layout components. Excludes `decorative` and `presentation`, which are only available on the full `AccessibilityRole` type. - `main`: The primary content of the page. - `header`: A page or section header. - `footer`: A section for copyright information, navigation links, and privacy statements. - `section`: A generic section; should have a heading or accessible label. - `complementary`: A supporting section related to the main content. - `navigation`: A major group of navigation links. - `orderedList`: A list of ordered items. - `listItem`: An item inside a list. - `unorderedList`: A list of unordered items. - `separator`: A divider separating sections of content. - `status`: A live region with advisory information that isn't urgent enough to be an alert. - `alert`: Important, usually time-sensitive information.

'main' | 'header' | 'footer' | 'section' | 'complementary' | 'navigation' | 'orderedList' | 'listItem' | 'unorderedList' | 'separator' | 'status' | 'alert'

MaybeConditionalStyle

A type that represents a value that can be a conditional style. We highly recommend using the `Style` helper which simplifies the creation of conditional styles.

T | ConditionalStyle<T, AcceptedConditions>

ConditionalStyle

A conditional style definition that maps one or more conditions to different values. The `default` value is used as a fallback when none of the conditions in `conditionals` are satisfied.

conditionals
An array of conditional values.
```
ConditionalValue<T, AcceptedConditions>[]
```
default
The default value applied when none of the conditional values specified in `conditionals` are met.
```
T
```

ConditionalValue

A single conditional branch that pairs a set of conditions with the value to apply when those conditions are met.

conditions
The conditions that must be met for the value to be applied. At least one condition must be specified.
```
AcceptedConditions
```
value
The value that will be applied if the conditions are met.
```
T
```

Background

A keyword that maps to a predefined background color from the design system. - `transparent`: No background color; the parent's background shows through. - `base`: The standard surface background color. - `subdued`: A muted background color, typically used to de-emphasize content or distinguish secondary areas from the primary surface.

'transparent' | 'base' | 'subdued'

MaybeResponsiveConditionalStyle

A type that represents a value that can be a conditional style. The conditions are based on the viewport size. We highly recommend using the `Style` helper which simplifies the creation of conditional styles.

T | ConditionalStyle<T, ViewportSizeCondition>

ViewportSizeCondition

A condition that targets layouts based on the inline size (width in horizontal writing modes) of the viewport.

viewportInlineSize
The minimum viewport inline size that the condition must match.
```
{ min: T; }
```

BlockAlignment

Controls how content is aligned along the block axis (vertical in standard writing modes). - `'start'`: Aligns content to the block start of the container. - `'center'`: Centers content along the block axis. - `'end'`: Aligns content to the block end of the container. - `'baseline'`: Aligns content so their text baselines line up.

Alignment | 'baseline'

Alignment

Controls how content is aligned along the cross axis. - `'start'`: Aligns content to the start of the container. - `'center'`: Centers content within the container. - `'end'`: Aligns content to the end of the container.

'start' | 'center' | 'end'

MaybeShorthandProperty

A type that accepts either a single value applied to all edges or a shorthand tuple for per-edge control. - `T`: A single value applied uniformly to all edges. - `[T, T]`: The first value applies to block-start and block-end, the second to inline-start and inline-end. - `[T, T, T, T]`: Values apply to block-start, inline-end, block-end, and inline-start respectively.

T | ShorthandProperty<T>

ShorthandProperty

A tuple type that accepts two or four values following the CSS shorthand convention for box edges. - `[T, T]`: The first value applies to block-start and block-end, the second to inline-start and inline-end. - `[T, T, T, T]`: Values apply to block-start, inline-end, block-end, and inline-start respectively.

[T, T] | [T, T, T, T]

BorderStyle

A keyword that maps to a predefined border style from the design system. - `base`: A solid border line, suitable for most use cases. - `dashed`: A dashed border line, often used for drop zones or placeholder boundaries. - `dotted`: A dotted border line. - `none`: No border is rendered.

'base' | 'dashed' | 'dotted' | 'none'

CornerRadius

A keyword that maps to a predefined corner radius from the design system. - `base`: The default corner radius. - `small`: A subtle corner radius, smaller than `base`. - `large`: A pronounced corner radius, larger than `base`. - `fullyRounded`: Fully rounds the corners into a pill or circle shape. - `none`: No corner rounding; sharp square corners.

'base' | 'small' | 'large' | 'fullyRounded' | 'none' | CornerRadiusDeprecated

CornerRadiusDeprecated

'tight' | 'loose'

BorderWidth

A keyword that maps to a predefined border width from the design system. - `base`: The default border width. - `medium`: A medium border width, thicker than `base`. - `thick`: The thickest available border width.

'base' | 'medium' | 'thick'

InlineAlignment

Controls how content is aligned along the inline axis (horizontal in standard writing modes). - `'start'`: Aligns content to the inline start of the container. - `'center'`: Centers content along the inline axis. - `'end'`: Aligns content to the inline end of the container.

'start' | 'center' | 'end'

Spacing

A keyword that maps to a predefined spacing value from the design system. Use these instead of pixel values to ensure consistent spacing throughout the UI. - `none`: No spacing (0px). - `extraTight`: The smallest amount of spacing. - `tight`: A compact amount of spacing, suitable for tight layouts. - `base`: The default spacing, appropriate for most layouts. - `loose`: A generous amount of spacing, used to create visual separation. - `extraLoose`: The largest amount of spacing.

'none' | 'extraTight' | 'tight' | 'base' | 'loose' | 'extraLoose'

Rows

The row sizing configuration for a grid-based layout. Accepts a single `GridItemSize` applied to all rows, or an array with one size per row.

GridItemSize[] | GridItemSize

GridItemSize

The size of a column or row in a grid-based layout. - `'auto'`: The intrinsic size of the content. - `'fill'`: Fills the remaining available space. When multiple items use `fill`, the space is shared equally. - `number`: A fixed size in pixels. - `` `${number}fr` ``: A fractional unit of the available space. - `` `${number}%` ``: A percentage of the container's size.

'auto' | 'fill' | number | `${number}fr` | `${number}%`

Anchor to ExamplesExamples

Anchor to Lay out content in rowsLay out content in rows

Use BlockLayout to arrange content in multiple rows. This example shows the default behavior where rows share the available block space equally.

Lay out content in rows

A BlockLayout component arranging content in multiple rows.

Lay out content in rows

import {

reactExtension,

BlockLayout,

View,

} from '@shopify/ui-extensions-react/customer-account';

export default reactExtension(

'customer-account.page.render',

() => <Extension />,

);

function Extension() {

return (

</View>

fill

</View>

</BlockLayout>

);

}

import {extension, BlockLayout, View} from '@shopify/ui-extensions/customer-account';

export default extension('customer-account.page.render', (root) => {

const blockLayout = root.createComponent(

BlockLayout,

{

rows: [60, 'fill'],

[

root.createComponent(View, {border: 'base', padding: 'base'}, '60'),

root.createComponent(View, {border: 'base', padding: 'base'}, 'fill'),

);

root.appendChild(blockLayout);

});

React

import {
  reactExtension,
  BlockLayout,
  View,
} from '@shopify/ui-extensions-react/customer-account';

export default reactExtension(
  'customer-account.page.render',
  () => <Extension />,
);

function Extension() {
  return (
    <BlockLayout rows={[60, 'fill']}>
      <View border="base" padding="base">
        60
      </View>
      <View border="base" padding="base">
        fill
      </View>
    </BlockLayout>
  );
}

JS

import {extension, BlockLayout, View} from '@shopify/ui-extensions/customer-account';

export default extension('customer-account.page.render', (root) => {
  const blockLayout = root.createComponent(
    BlockLayout,
    {
      rows: [60, 'fill'],
    },
    [
      root.createComponent(View, {border: 'base', padding: 'base'}, '60'),
      root.createComponent(View, {border: 'base', padding: 'base'}, 'fill'),
    ],
  );

  root.appendChild(blockLayout);
});

Anchor to Best practicesBest practices

Use explicit row sizes for unequal layouts: Set the rows prop with specific sizes when rows should have different proportions. Default equal distribution works well for balanced layouts.
Choose BlockLayout over BlockStack for row control: Use BlockLayout when you need to define explicit row sizes. For uniform vertical spacing between elements, BlockStack is simpler.
Combine with StyleHelper for responsiveness: Use StyleHelper to adjust row sizes at different viewport breakpoints.

Anchor to LimitationsLimitations

BlockLayout fills the available block space by default. Children can't exceed the container height without setting overflow.
Row sizes are defined as a flat array. You can't assign sizes to specific rows by name.
BlockLayout doesn't support column-based layouts. Use InlineLayout or Grid for columns.

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