---
title: ui_extension_errored
description: |-
  The `ui_extension_errored` event logs occurrences when an extension fails to render due to an uncaught exception in the extension code.

  > Note: This event is only available on checkout.
api_name: web-pixels
source_url:
  html: https://shopify.dev/docs/api/web-pixels-api/standard-events/ui_extension_errored
  md: https://shopify.dev/docs/api/web-pixels-api/standard-events/ui_extension_errored.md
---

# ui\_​extension\_​erroredinterface

The `ui_extension_errored` event logs occurrences when an extension fails to render due to an uncaught exception in the extension code.

Note

This event is only available on checkout.

## Properties

* clientId

  string

  The client-side ID of the customer, provided by Shopify

* context

  Context

* data

  PixelEventsUiExtensionErroredData

* id

  string

  The ID of the customer event

* name

  string

  The name of the customer event

* seq

  number

  The sequence index number of the event.

* timestamp

  string

  The timestamp of when the customer event occurred, in [ISO 8601](https://en.wikipedia.org/wiki/ISO_8601) format

* type

  EventType.Standard

### Context

A snapshot of various read-only properties of the browser at the time of event

* document

  Snapshot of a subset of properties of the \`document\` object in the top frame of the browser

  ```ts
  WebPixelsDocument
  ```

* navigator

  Snapshot of a subset of properties of the \`navigator\` object in the top frame of the browser

  ```ts
  WebPixelsNavigator
  ```

* window

  Snapshot of a subset of properties of the \`window\` object in the top frame of the browser

  ```ts
  WebPixelsWindow
  ```

```ts
export interface Context {
  /**
   * Snapshot of a subset of properties of the `document` object in the top
   * frame of the browser
   */
  document?: WebPixelsDocument;

  /**
   * Snapshot of a subset of properties of the `navigator` object in the top
   * frame of the browser
   */
  navigator?: WebPixelsNavigator;

  /**
   * Snapshot of a subset of properties of the `window` object in the top frame
   * of the browser
   */
  window?: WebPixelsWindow;
}
```

### WebPixelsDocument

A snapshot of a subset of properties of the \`document\` object in the top frame of the browser

* characterSet

  Per \[MDN]\(https\://developer.mozilla.org/en-US/docs/Web/API/Document), returns the character set being used by the document

  ```ts
  string
  ```

* location

  Per \[MDN]\(https\://developer.mozilla.org/en-US/docs/Web/API/Document), returns the URI of the current document

  ```ts
  Location
  ```

* referrer

  Per \[MDN]\(https\://developer.mozilla.org/en-US/docs/Web/API/Document), returns the URI of the page that linked to this page

  ```ts
  string
  ```

* title

  Per \[MDN]\(https\://developer.mozilla.org/en-US/docs/Web/API/Document), returns the title of the current document

  ```ts
  string
  ```

```ts
export interface WebPixelsDocument {
  /**
   * Per [MDN](https://developer.mozilla.org/en-US/docs/Web/API/Document),
   * returns the character set being used by the document
   */
  characterSet?: string;

  /**
   * Per [MDN](https://developer.mozilla.org/en-US/docs/Web/API/Document),
   * returns the URI of the current document
   */
  location?: Location;

  /**
   * Per [MDN](https://developer.mozilla.org/en-US/docs/Web/API/Document),
   * returns the URI of the page that linked to this page
   */
  referrer?: string;

  /**
   * Per [MDN](https://developer.mozilla.org/en-US/docs/Web/API/Document),
   * returns the title of the current document
   */
  title?: string;
}
```

### Location

A snapshot of a subset of properties of the \`location\` object in the top frame of the browser

* hash

  Per \[MDN]\(https\://developer.mozilla.org/en-US/docs/Web/API/Location), a string containing a \`'#'\` followed by the fragment identifier of the URL

  ```ts
  string
  ```

* host

  Per \[MDN]\(https\://developer.mozilla.org/en-US/docs/Web/API/Location), a string containing the host, that is the hostname, a \`':'\`, and the port of the URL

  ```ts
  string
  ```

* hostname

  Per \[MDN]\(https\://developer.mozilla.org/en-US/docs/Web/API/Location), a string containing the domain of the URL

  ```ts
  string
  ```

* href

  Per \[MDN]\(https\://developer.mozilla.org/en-US/docs/Web/API/Location), a string containing the entire URL

  ```ts
  string
  ```

* origin

  Per \[MDN]\(https\://developer.mozilla.org/en-US/docs/Web/API/Location), a string containing the canonical form of the origin of the specific location

  ```ts
  string
  ```

* pathname

  Per \[MDN]\(https\://developer.mozilla.org/en-US/docs/Web/API/Location), a string containing an initial \`'/'\` followed by the path of the URL, not including the query string or fragment

  ```ts
  string
  ```

* port

  Per \[MDN]\(https\://developer.mozilla.org/en-US/docs/Web/API/Location), a string containing the port number of the URL

  ```ts
  string
  ```

* protocol

  Per \[MDN]\(https\://developer.mozilla.org/en-US/docs/Web/API/Location), a string containing the protocol scheme of the URL, including the final \`':'\`

  ```ts
  string
  ```

* search

  Per \[MDN]\(https\://developer.mozilla.org/en-US/docs/Web/API/Location), a string containing a \`'?'\` followed by the parameters or "querystring" of the URL

  ```ts
  string
  ```

```ts
export interface Location {
  /**
   * Per [MDN](https://developer.mozilla.org/en-US/docs/Web/API/Location), a
   * string containing a `'#'` followed by the fragment identifier of the URL
   */
  hash?: string;

  /**
   * Per [MDN](https://developer.mozilla.org/en-US/docs/Web/API/Location), a
   * string containing the host, that is the hostname, a `':'`, and the port of
   * the URL
   */
  host?: string;

  /**
   * Per [MDN](https://developer.mozilla.org/en-US/docs/Web/API/Location), a
   * string containing the domain of the URL
   */
  hostname?: string;

  /**
   * Per [MDN](https://developer.mozilla.org/en-US/docs/Web/API/Location), a
   * string containing the entire URL
   */
  href?: string;

  /**
   * Per [MDN](https://developer.mozilla.org/en-US/docs/Web/API/Location), a
   * string containing the canonical form of the origin of the specific location
   */
  origin?: string;

  /**
   * Per [MDN](https://developer.mozilla.org/en-US/docs/Web/API/Location), a
   * string containing an initial `'/'` followed by the path of the URL, not
   * including the query string or fragment
   */
  pathname?: string;

  /**
   * Per [MDN](https://developer.mozilla.org/en-US/docs/Web/API/Location), a
   * string containing the port number of the URL
   */
  port?: string;

  /**
   * Per [MDN](https://developer.mozilla.org/en-US/docs/Web/API/Location), a
   * string containing the protocol scheme of the URL, including the final `':'`
   */
  protocol?: string;

  /**
   * Per [MDN](https://developer.mozilla.org/en-US/docs/Web/API/Location), a
   * string containing a `'?'` followed by the parameters or "querystring" of
   * the URL
   */
  search?: string;
}
```

### WebPixelsNavigator

A snapshot of a subset of properties of the \`navigator\` object in the top frame of the browser

* cookieEnabled

  Per \[MDN]\(https\://developer.mozilla.org/en-US/docs/Web/API/Navigator), returns \`false\` if setting a cookie will be ignored and true otherwise

  ```ts
  boolean
  ```

* language

  Per \[MDN]\(https\://developer.mozilla.org/en-US/docs/Web/API/Navigator), returns a string representing the preferred language of the user, usually the language of the browser UI. The \`null\` value is returned when this is unknown

  ```ts
  string
  ```

* languages

  Per \[MDN]\(https\://developer.mozilla.org/en-US/docs/Web/API/Navigator), returns an array of strings representing the languages known to the user, by order of preference

  ```ts
  ReadonlyArray<string>
  ```

* userAgent

  Per \[MDN]\(https\://developer.mozilla.org/en-US/docs/Web/API/Navigator), returns the user agent string for the current browser

  ```ts
  string
  ```

```ts
export interface WebPixelsNavigator {
  /**
   * Per [MDN](https://developer.mozilla.org/en-US/docs/Web/API/Navigator),
   * returns `false` if setting a cookie will be ignored and true otherwise
   */
  cookieEnabled?: boolean;

  /**
   * Per [MDN](https://developer.mozilla.org/en-US/docs/Web/API/Navigator),
   * returns a string representing the preferred language of the user, usually
   * the language of the browser UI. The `null` value is returned when this
   * is unknown
   */
  language?: string;

  /**
   * Per [MDN](https://developer.mozilla.org/en-US/docs/Web/API/Navigator),
   * returns an array of strings representing the languages known to the user,
   * by order of preference
   */
  languages?: ReadonlyArray<string>;

  /**
   * Per [MDN](https://developer.mozilla.org/en-US/docs/Web/API/Navigator),
   * returns the user agent string for the current browser
   */
  userAgent?: string;
}
```

### WebPixelsWindow

A snapshot of a subset of properties of the \`window\` object in the top frame of the browser

* innerHeight

  Per \[MDN]\(https\://developer.mozilla.org/en-US/docs/Web/API/Window), gets the height of the content area of the browser window including, if rendered, the horizontal scrollbar

  ```ts
  number
  ```

* innerWidth

  Per \[MDN]\(https\://developer.mozilla.org/en-US/docs/Web/API/Window), gets the width of the content area of the browser window including, if rendered, the vertical scrollbar

  ```ts
  number
  ```

* location

  Per \[MDN]\(https\://developer.mozilla.org/en-US/docs/Web/API/Window), the location, or current URL, of the window object

  ```ts
  Location
  ```

* origin

  Per \[MDN]\(https\://developer.mozilla.org/en-US/docs/Web/API/Window), the global object's origin, serialized as a string

  ```ts
  string
  ```

* outerHeight

  Per \[MDN]\(https\://developer.mozilla.org/en-US/docs/Web/API/Window), gets the height of the outside of the browser window

  ```ts
  number
  ```

* outerWidth

  Per \[MDN]\(https\://developer.mozilla.org/en-US/docs/Web/API/Window), gets the width of the outside of the browser window

  ```ts
  number
  ```

* pageXOffset

  Per \[MDN]\(https\://developer.mozilla.org/en-US/docs/Web/API/Window), an alias for window\.scrollX

  ```ts
  number
  ```

* pageYOffset

  Per \[MDN]\(https\://developer.mozilla.org/en-US/docs/Web/API/Window), an alias for window\.scrollY

  ```ts
  number
  ```

* screen

  Per \[MDN]\(https\://developer.mozilla.org/en-US/docs/Web/API/Screen), the interface representing a screen, usually the one on which the current window is being rendered

  ```ts
  Screen
  ```

* screenX

  Per \[MDN]\(https\://developer.mozilla.org/en-US/docs/Web/API/Window), the horizontal distance from the left border of the user's browser viewport to the left side of the screen

  ```ts
  number
  ```

* screenY

  Per \[MDN]\(https\://developer.mozilla.org/en-US/docs/Web/API/Window), the vertical distance from the top border of the user's browser viewport to the top side of the screen

  ```ts
  number
  ```

* scrollX

  Per \[MDN]\(https\://developer.mozilla.org/en-US/docs/Web/API/Window), the number of pixels that the document has already been scrolled horizontally

  ```ts
  number
  ```

* scrollY

  Per \[MDN]\(https\://developer.mozilla.org/en-US/docs/Web/API/Window), the number of pixels that the document has already been scrolled vertically

  ```ts
  number
  ```

```ts
export interface WebPixelsWindow {
  /**
   * Per [MDN](https://developer.mozilla.org/en-US/docs/Web/API/Window),
   * gets the height of the content area of the browser window including, if
   * rendered, the horizontal scrollbar
   */
  innerHeight?: number;

  /**
   * Per [MDN](https://developer.mozilla.org/en-US/docs/Web/API/Window), gets
   * the width of the content area of the browser window including, if rendered,
   * the vertical scrollbar
   */
  innerWidth?: number;

  /**
   * Per [MDN](https://developer.mozilla.org/en-US/docs/Web/API/Window), the
   * location, or current URL, of the window object
   */
  location?: Location;

  /**
   * Per [MDN](https://developer.mozilla.org/en-US/docs/Web/API/Window), the
   * global object's origin, serialized as a string
   */
  origin?: string;

  /**
   * Per [MDN](https://developer.mozilla.org/en-US/docs/Web/API/Window), gets
   * the height of the outside of the browser window
   */
  outerHeight?: number;

  /**
   * Per [MDN](https://developer.mozilla.org/en-US/docs/Web/API/Window), gets
   * the width of the outside of the browser window
   */
  outerWidth?: number;

  /**
   * Per [MDN](https://developer.mozilla.org/en-US/docs/Web/API/Window), an
   * alias for window.scrollX
   */
  pageXOffset?: number;

  /**
   * Per [MDN](https://developer.mozilla.org/en-US/docs/Web/API/Window), an
   * alias for window.scrollY
   */
  pageYOffset?: number;

  /**
   * Per [MDN](https://developer.mozilla.org/en-US/docs/Web/API/Screen), the
   * interface representing a screen, usually the one on which the current
   * window is being rendered
   */
  screen?: Screen;

  /**
   * Per [MDN](https://developer.mozilla.org/en-US/docs/Web/API/Window), the
   * horizontal distance from the left border of the user's browser viewport to
   * the left side of the screen
   */
  screenX?: number;

  /**
   * Per [MDN](https://developer.mozilla.org/en-US/docs/Web/API/Window), the
   * vertical distance from the top border of the user's browser viewport to the
   * top side of the screen
   */
  screenY?: number;

  /**
   * Per [MDN](https://developer.mozilla.org/en-US/docs/Web/API/Window), the
   * number of pixels that the document has already been scrolled horizontally
   */
  scrollX?: number;

  /**
   * Per [MDN](https://developer.mozilla.org/en-US/docs/Web/API/Window), the
   * number of pixels that the document has already been scrolled vertically
   */
  scrollY?: number;
}
```

### Screen

The interface representing a screen, usually the one on which the current window is being rendered

* height

  Per \[MDN]\(https\://developer.mozilla.org/en-US/docs/Web/API/Screen/height), the height of the screen

  ```ts
  number
  ```

* width

  Per \[MDN]\(https\://developer.mozilla.org/en-US/docs/Web/API/Screen/width), the width of the screen

  ```ts
  number
  ```

```ts
export interface Screen {
  /**
   * Per [MDN](https://developer.mozilla.org/en-US/docs/Web/API/Screen/height),
   * the height of the screen
   */
  height?: number;

  /**
   * Per [MDN](https://developer.mozilla.org/en-US/docs/Web/API/Screen/width),
   * the width of the screen
   */
  width?: number;
}
```

### PixelEventsUiExtensionErroredData

* error

  ```ts
  UiExtensionError
  ```

```ts
export interface PixelEventsUiExtensionErroredData {
  error?: UiExtensionError;
}
```

### UiExtensionError

An object that contains data about a UI Extension error that occurred.

* apiVersion

  The API version used by the extension.

  ```ts
  string
  ```

* appId

  The unique identifier of the app that the extension belongs to.

  ```ts
  string
  ```

* appName

  The name of the app that the extension belongs to.

  ```ts
  string
  ```

* appVersion

  The version of the app that encountered the error.

  ```ts
  string
  ```

* extensionName

  The name of the extension that encountered the error.

  ```ts
  string
  ```

* extensionTarget

  The \[target]\(https\://shopify.dev/docs/api/checkout-ui-extensions/latest/targets) of the extension, for example "purchase.checkout.delivery-address.render-after".

  ```ts
  string
  ```

* message

  The message associated with the error that occurred.

  ```ts
  string
  ```

* placementReference

  The \[placement reference]\(https\://shopify.dev/docs/apps/build/checkout/test-checkout-ui-extensions#dynamic-targets) of the extension, only populated for dynamic targets.

  ```ts
  string | null
  ```

* trace

  The stack trace associated with the error that occurred.

  ```ts
  string
  ```

* type

  The type of error that occurred.

  ```ts
  UiExtensionErrorType
  ```

```ts
export interface UiExtensionError {
  /**
   * The API version used by the extension.
   */
  apiVersion?: string;

  /**
   * The unique identifier of the app that the extension belongs to.
   */
  appId?: string;

  /**
   * The name of the app that the extension belongs to.
   */
  appName?: string;

  /**
   * The version of the app that encountered the error.
   */
  appVersion?: string;

  /**
   * The name of the extension that encountered the error.
   */
  extensionName?: string;

  /**
   * The [target](https://shopify.dev/docs/api/checkout-ui-extensions/latest/targets) of the extension, for example
   * "purchase.checkout.delivery-address.render-after".
   */
  extensionTarget?: string;

  /**
   * The message associated with the error that occurred.
   */
  message?: string;

  /**
   * The [placement reference](https://shopify.dev/docs/apps/build/checkout/test-checkout-ui-extensions#dynamic-targets) of the extension, only populated
   * for dynamic targets.
   */
  placementReference?: string | null;

  /**
   * The stack trace associated with the error that occurred.
   */
  trace?: string;

  /**
   * The type of error that occurred.
   */
  type?: UiExtensionErrorType;
}
```

### UiExtensionErrorType

* ExtensionUsageError

  ```ts
  EXTENSION_USAGE_ERROR
  ```

```ts
export enum UiExtensionErrorType {
  /**
   * An error caused by incorrect usage of extension APIs or UI components.
   */
  ExtensionUsageError = 'EXTENSION_USAGE_ERROR',
}
```

### EventType

* AdvancedDom

  ```ts
  advanced-dom
  ```

* Custom

  ```ts
  custom
  ```

* Dom

  ```ts
  dom
  ```

* Meta

  ```ts
  meta
  ```

* Standard

  ```ts
  standard
  ```

```ts
export enum EventType {
  AdvancedDom = 'advanced-dom',
  Custom = 'custom',
  Dom = 'dom',
  Meta = 'meta',
  Standard = 'standard',
}
```

### Examples

* #### Accessing Standard Events

  ##### App Pixel

  ```javascript
  import {register} from '@shopify/web-pixels-extension';

  register(({analytics}) => {
    analytics.subscribe('ui_extension_errored', (event) => {
      // Example for accessing event data
      const {apiVersion, appId, appName, appVersion, trace} = event.data.alert;

      const payload = {
        event_name: event.name,
        event_data: {
          apiVersion,
          appId,
          appName,
          appVersion,
          trace,
        },
      };

      // Example for sending event data to third party servers
      fetch('https://example.com/pixel', {
        method: 'POST',
        body: JSON.stringify(payload),
        keepalive: true,
      });
    });
  });
  ```

  ##### Custom Pixel

  ```javascript
  analytics.subscribe('ui_extension_errored', (event) => {
    // Example for accessing event data
    const {apiVersion, appId, appName, appVersion, trace} = event.data.alert;

    const payload = {
      event_name: event.name,
      event_data: {
        apiVersion,
        appId,
        appName,
        appVersion,
        trace,
      },
    };

    // Example for sending event to third party servers
    fetch('https://example.com/pixel', {
      method: 'POST',
      body: JSON.stringify(payload),
      keepalive: true,
    });
  });
  ```