---
title: Using Polaris web components
description: >-
  Polaris web components are Shopify’s UI toolkit for building interfaces that
  match the Shopify Checkout design system. This toolkit provides a set of
  custom HTML elements (web components) that you can use to create consistent,
  accessible, and performant user interfaces for the Checkout UI Extensions.
api_version: 2025-10
api_name: checkout-ui-extensions
source_url:
  html: >-
    https://shopify.dev/docs/api/checkout-ui-extensions/latest/using-polaris-components
  md: >-
    https://shopify.dev/docs/api/checkout-ui-extensions/latest/using-polaris-components.md
---

# Using Polaris web components

Polaris web components are Shopify’s UI toolkit for building interfaces that match the Shopify Checkout design system. This toolkit provides a set of custom HTML elements (web components) that you can use to create consistent, accessible, and performant user interfaces for the Checkout UI Extensions.

***

## Styling

Polaris web components come with built-in styling that follows Shopify’s design system. The components will automatically apply the correct styling based on the properties you set and the context in which they are used. For example, headings automatically display at progressively less prominent sizes based on how many levels deep they are nested inside of sections. All components inherit a merchant’s brand settings and the CSS cannot be altered or overridden.

### Examples

* #### Example

  ##### JSX

  ```jsx
  <s-box
    padding="base"
    background="subdued"
    border="base"
    borderRadius="base"
    class="my-custom-class"
  >
    Content
  </s-box>
  ```

## Custom layout

When you need to build custom layouts you can use `s-stack`, `s-grid` and `s-box`.

* `s-stack` and `s-grid` do not include spacing between children by default. To apply white space between children use the `gap` property
* When `s-stack` is `direction="inline"` it will automatically wrap children to a new line when space is limited.
* `s-grid` will allow children to overflow unless template rows/columns are properly set.
* Order is important for shorthand properties, e.g. border takes `size-keyword`, `color-keyword`, `style-keyword`

## Scale

Our components use a middle-out scale for multiple properties like `padding`, `size` and `gap`.

Our scale moves from the middle out:

* `small-300` is smaller than `small-100`
* `large-300` is bigger than `large-100`
* `small-100` and `large-100` have aliases of `small` and `large`
* `base` is the default value

### Examples

* #### Example

  ##### Default

  ```ts
  export type Scale =
    | 'small-300'
    | 'small-200'
    | 'small-100'
    | 'small' // alias of small-100
    | 'base'
    | 'large' // alias of large-100
    | 'large-100'
    | 'large-200'
    | 'large-300';
  ```

## Responsive values

Some properties accept responsive values, which enables you to change the value of the property depending on a parent inline size.

Syntax

The syntax for a responsive value generally follows the ternary operator syntax. For example, `@container (inline-size > 500px) large, small` means that the value will be `large` if the container is more than 500px wide, and `small` if the container is 500px or less. The syntax rules are:

1. Begin the value with `@container`
2. Optionally add a name to target a specific container
3. Use the `inline-size` keyword inside of parentheses to query the inline-size of the container. This is the condition that will be evaluated to determine which value to use.
4. Set the value if that condition is true
5. Set the value to be used if the condition is false.

For greater compatibility on older browsers, container queries must follow a mobile-first approach. The fallback value (when the condition is false) must always represent your smallest supported design, with the condition value (when the condition is true) providing styles for larger containers. For example, `<Stack direction="@container (inline-size > 300px) inline, block">` ensures that browsers that do not support container styles get a design that works in all container sizes.

Using s-query-container

When using responsive values, you must also place the `<s-query-container>` component in the location you want to query the inline-size.

By default, the responsive value will query against the closest parent; to look up a specific parent, this component also accepts a `containername` attribute which adds a name to the container. Then add that name after `@container` in your responsive query to target it.

Values with reserved characters

Some values could contain reserved characters used in the responsive value syntax, such as `()` or `,`. To use these values, escape them by wrapping them in quotes.

Advanced patterns

The syntax is flexible enough to support advanced patterns such as compound conditions, and|or conditions, and nested conditions.

### Examples

* ####

  ##### HTML

  ```html
  <s-box
    padding="@container (inline-size > 500px) large-400, small"
  >
    This padding will be "large-400" when the
    container is more than 500px. Otherwise it will
    be "small".
  </s-box>
  ```

## Interactive elements

`s-button`, `s-link` and `s-clickable` render as anchor elements when they have a `href` and render as a button element when they have an `onClick` without a `href`. The HTML specification states that interactive elements cannot have interactive children.

`s-clickable` is an escape hatch for when `s-link` and `s-button` are not able to implement a specific design. You should always try to use `s-link` and `s-button` first.

Interactive components with `target="auto"` automatically use `_self` for internal links and `_blank` for external URLs. This behavior ensures a consistent navigation experience for users without requiring developers to manually set the correct target for each link.

## Variant tone and color

The `tone` is used to apply a group of color design tokens to the component such as `critical`, `success` or `info`.

The `color` adjusts the intensity of the `tone` making it more `subdued` or `strong`.

The `variant` is used to change how the component is rendered to match the design language this is different for each component.

### Examples

* #### Example

  ##### Default

  ```jsx
  <s-button tone="critical" variant="primary">
    Primary Critical Button
  </s-button>
  <s-badge tone="success" color="strong">
    Success Strong Badge
  </s-badge>
  ```

## Using with Preact

For UI Extensions, Shopify provides Preact as the framework of choice. Using Polaris web components with Preact is very similar to using them with React.

### Examples

* #### Example

  ##### JSX

  ```jsx
  export function ProductExtension() {
    return (
      <s-box padding="base">
        <s-stack gap="base">
          <s-text>Enable special pricing</s-text>
          <s-checkbox onChange={() => console.log('Checkbox toggled')} />
          <s-number-field
            label="Discount percentage"
            suffix="%"
            min="0"
            max="100"
          />
        </s-stack>
      </s-box>
    );
  }
  ```

## Properties vs attributes

Polaris web components follow the same property and attribute patterns as standard HTML elements. Understanding this distinction is important for using the components effectively.

Key concepts

1. **Attributes** are HTML attributes that appear in the HTML markup.
2. **Properties** are JavaScript object properties accessed directly on the DOM element.
3. Most attributes in Polaris web components are reflected as properties, with a few exceptions like `value` and `checked` which follow HTML’s standard behavior.

How JSX properties are applied

When using Polaris web components in JSX, the framework determines how to apply your props based on whether the element has a matching property name.

If the element has a property with the exact same name as your prop, the value is set as a property. Otherwise, it’s applied as an attribute. Here’s how this works in pseudocode:

Examples

For Polaris web components, you can generally just use the property names as documented, and everything will work as expected.

### Examples

* ####

## Event Handling

Polaris web components use standard DOM events, making them work seamlessly with your preferred framework. You can attach event handlers using the same patterns as with native HTML elements.

Basic Event Handling

Event handlers in Polaris components work just like standard HTML elements. In frameworks, use the familiar camelCase syntax (like `onClick` in Preact). In plain HTML, use lowercase attributes or `addEventListener`.

Form Input Events

Polaris form components support two primary event types for tracking input changes:

* **onInput**: Fires immediately on every keystroke or value change
* **onChange**: Fires when the value is committed; for text fields that happens on blur; for checkboxes and radio buttons immediately after `onInput`.

Choose the appropriate event based on your needs:

* Use `onInput` for real-time validation or character counting
* Use `onChange` for validation after a user completes their input

Focus Management

Track when users interact with form elements using these events:

* **onFocus**: Fires when an element receives focus
* **onBlur**: Fires when an element loses focus

Form Values and Types

Important details about form values in Polaris web components:

* All form elements return string values in their events, even numeric inputs
* Multi-select components (like `s-choice-list`) use a `values` prop (array of strings)
* Access values in event handlers via `event.currentTarget.value`

Controlled vs. Uncontrolled Components

Polaris components can be used in two ways: **Uncontrolled (simpler)**: Component manages its own internal state - use `defaultValue` prop **Controlled (more powerful)**: Your code manages the component’s state - use `value` prop

Use controlled components when you need to:

* Validate input as the user types
* Format or transform input values
* Synchronize multiple inputs

Technical Details

Under the hood, Polaris web components handle event registration consistently across frameworks:

* In Preact, Polaris components properly register events via `addEventListener` instead of setting attributes
* Event names are automatically converted to lowercase (`onClick` becomes `click`)
* All event handlers receive standard DOM events as their first argument

For example, when you write `<s-button onClick={handleClick}>`, the component:

1. Sees that `"onclick" in element` is `true`
2. Registers your handler via `addEventListener('click', handler)`
3. Passes the event object to your handler when clicked

### Examples

* #### Basic Event Handling Examples

  ##### JSX

  ```jsx
  <s-button onClick={() => console.log('Clicked!')}>
    Inline Handler
  </s-button>

  <s-button onClick={(event) => {
    console.log('Event details:', event.type);
    console.log('Target:', event.currentTarget);
  }}>
    With Event Object
  </s-button>
  ```

  ##### HTML

  ```html
  <s-button onclick="console.log('Button clicked!')">
    Click me
  </s-button>

  <s-button id="eventButton">
    Click me (addEventListener)
  </s-button>

  <script>
    const eventButton = document.getElementById('eventButton');

    eventButton.addEventListener('click', () => {
      console.log('Button clicked via addEventListener!');
    });
  </script>
  ```

## Slots

Slots allow you to insert custom content into specific areas of Polaris web components. Use the `slot` attribute to specify where your content should appear within a component.

Key points:

* Named slots (e.g., `slot="title"`) place content in designated areas
* Multiple elements can share the same slot name
* Elements without a slot attribute go into the default (unnamed) slot

### Examples

* #### Examples

  ##### Banner

  ```jsx
  <s-banner heading="Order created" status="success">
    The order has been created successfully.
    <s-button slot="secondary-actions">View order</s-button>
    <s-button slot="secondary-actions">Download invoice</s-button>
  </s-banner>
  ```

## Methods

Methods are functions available on components for programmatic control. Components like `Modal`, `Sheet`, and `Announcement` provide methods such as `hideOverlay()` or `dismiss()` to control their behavior imperatively when needed.

Use methods when you need to trigger actions that can’t be achieved through property changes alone, such as closing an overlay after an async operation or resetting component state.

### Examples

* #### Example

  ##### JSX

  ```jsx
  function Methods() {
    const modalRef = useRef(null);

    return (
      <>
        <s-button
          command="--show"
          commandFor="modal-1"
        >
          Open modal
        </s-button>
        <s-modal
          id="modal-1"
          ref={modalRef}
          heading="Test Modal"
        >
          <s-text>Modal content</s-text>
          <s-button
            onClick={() => {
              modalRef.current.hideOverlay();
            }}
          >
            Close modal
          </s-button>
        </s-modal>
      </>
    );
  }
  ```

  ##### JS

  ```js
  function Methods() {
    const button =
      document.createElement('s-button');
    const modal = document.createElement('s-modal');

    button.textContent = 'Open Modal';
    button.commandFor = 'modal-1';

    modal.id = 'modal-1';
    modal.heading = 'Test Modal';

    const closeButton =
      document.createElement('s-button');

    closeButton.textContent = 'Close modal';
    closeButton.onclick = () => modal.hideOverlay();

    modal.appendChild(closeButton);

    document.body.appendChild(button);
    document.body.appendChild(modal);
  }
  ```

## Using Forms

The [Form](https://shopify.dev/docs/api/checkout-ui-extensions/2025-10/components/forms/form) component provides a way to manage form state and submit data to your app’s backend or directly to Shopify using Direct API access. When the form is submitted or reset the relevant callback in the form component will get triggered.

Using this, you can control what defines a component to be dirty by utilizing the input’s defaultValue property.

Rules:

* When the `defaultValue` is set, the component will be considered dirty if the value of the input is different from the `defaultValue`. You may update the `defaultValue` when the form is submitted to reset the dirty state of the form.

* When the `defaultValue` is not set, the component will be considered dirty if the value of the input is different from the initial value or from the last dynamic update to the input’s value that wasn’t triggered by user input.

Note: In order to trigger the dirty state, each input must have a name attribute.

### Examples

* #### Trigger the Form’s dirty state

  ##### Using \`defaultValue\`

  ```tsx
  import { render } from 'preact';
  import { useState } from 'preact/hooks';

  export default function extension() {
    render(<Extension />, document.body);
  }

  const defaultValues = {
    text: 'default value',
    number: 50,
  };

  function Extension() {
    const [textValue, setTextValue] = useState('');
    const [numberValue, setNumberValue] = useState('');

    return (
        <s-form onSubmit={() => console.log('submit', {textValue, numberValue})}>
          <s-stack gap="base">
            <s-text-field
              label="Default Value"
              name="my-text"
              defaultValue={defaultValues.text}
              value={textValue}
              onChange={(e) => setTextValue(e.target.value)}
            />
            <s-number-field
              label="Percentage field"
              name="my-number"
              defaultValue={defaultValues.number}
              value={numberValue}
              onChange={(e) => setNumberValue(e.target.value)}
            />
          </s-stack>
        </s-form>
    );
  }
  ```

  ##### Using implicit default

  ```tsx
  import { render } from 'preact';
  import { useState } from 'preact/hooks';

  export default function extension() {
    render(<Extension />, document.body);
  }

  async function Extension() {
    const data = await fetch('/data.json');
    const {text, number} = await data.json();
    return <App text={text} number={number} />;
  }

  function App({text, number}) {
    // The initial values set in the form fields will be the default values
    const [textValue, setTextValue] = useState(text);
    const [numberValue, setNumberValue] = useState(number);

    return (
        <s-form onSubmit={() => console.log('submit', {textValue, numberValue})}>
          <s-stack gap="base">
            <s-text-field
              label="Default Value"
              name="my-text"
              value={textValue}
              onChange={(e) => setTextValue(e.target.value)}
            />
            <s-number-field
              label="Percentage field"
              name="my-number"
              value={numberValue}
              onChange={(e) => setNumberValue(e.target.value)}
            />
          </s-stack>
        </s-form>
    );
  }
  ```

## Accessibility

Polaris web components are built with accessibility in mind. They:

* Use semantic HTML under the hood
* Support keyboard navigation
* Include proper ARIA attributes
* Manage focus appropriately
* Provide appropriate color contrast
* Log warnings when component properties are missing and required for accessibility

To ensure your application remains accessible, follow these best practices:

1. Always use the `label` and `error` properties for form elements
2. Use appropriate heading levels with `s-heading` or the `heading` property
3. Ensure sufficient color contrast
4. Test keyboard navigation
5. Use `labelAccessibilityVisibility` to hide labels and keep them visible to assistive technologies
6. Use `accessibilityRole` to specify the `aria-role` of the component

### Examples

* #### Example

  ##### JSX

  ```jsx
  {/* Good - provides a label */}
  <s-text-field label="Email address"></s-text-field>

  {/* Bad - missing a label */}
  <s-text-field></s-text-field>
  ```

## Troubleshooting

Common issues and debugging tips for using Polaris web components.

Common issues

1. **Properties not updating**: Ensure you’re using the property name as documented, not a different casing or naming convention.
2. **Event handlers not firing**: Check that you’re using the correct event name (e.g., `onClick` for click events).
3. **Form values not being submitted**: Make sure your form elements have `name` attributes.

Debugging tips

1. Inspect the element in your browser’s developer tools to see the current property and attribute values.
2. Use `console.log` to verify that event handlers are being called and receiving the expected event objects.
3. Check for any errors in the browser console that might indicate issues with your component usage.

### Examples

* ####