Immersive Reader JavaScript SDK Reference (v1.2)

The Immersive Reader SDK contains a JavaScript library that allows you to integrate the Immersive Reader into your application.

You may use npm, yarn, or an HTML <script> element to include the library of the latest stable build in your web application:

<script type='text/javascript' src=''></script>
npm install @microsoft/immersive-reader-sdk
yarn add @microsoft/immersive-reader-sdk


The SDK exposes the functions:


Launches the Immersive Reader within an HTML iframe element in your web application. The size of your content is limited to a maximum of 50 MB.

launchAsync(token: string, subdomain: string, content: Content, options?: Options): Promise<LaunchResponse>;

launchAsync Parameters

Name Type Description
token string The Microsoft Entra authentication token. For more information, see How-To Create an Immersive Reader Resource.
subdomain string The custom subdomain of your Immersive Reader resource in Azure. For more information, see How-To Create an Immersive Reader Resource.
content Content An object containing the content to be shown in the Immersive Reader.
options Options Options for configuring certain behaviors of the Immersive Reader. Optional.


Returns a Promise<LaunchResponse>, which resolves when the Immersive Reader is loaded. The Promise resolves to a LaunchResponse object.


The returned Promise will be rejected with an Error object if the Immersive Reader fails to load. For more information, see the error codes.


Closes the Immersive Reader.

An example use case for this function is if the exit button is hidden by setting hideExitButton: true in options. Then, a different button (for example a mobile header's back arrow) can call this close function when it's clicked.

close(): void;

Immersive Reader Launch Button

The SDK provides default styling for the button for launching the Immersive Reader. Use the immersive-reader-button class attribute to enable this styling. For more information, see How-To Customize the Immersive Reader button.

<div class='immersive-reader-button'></div>

Optional attributes

Use the following attributes to configure the look and feel of the button.

Attribute Description
data-button-style Sets the style of the button. Can be icon, text, or iconAndText. Defaults to icon.
data-locale Sets the locale. For example, en-US or fr-FR. Defaults to English en.
data-icon-px-size Sets the size of the icon in pixels. Defaults to 20px.


The renderButtons function isn't necessary if you're using the How-To Customize the Immersive Reader button guidance.

This function styles and updates the document's Immersive Reader button elements. If options.elements is provided, then the buttons will be rendered within each element provided in options.elements. Using the options.elements parameter is useful when you have multiple sections in your document on which to launch the Immersive Reader, and want a simplified way to render multiple buttons with the same styling, or want to render the buttons with a simple and consistent design pattern. To use this function with the renderButtons options parameter, call ImmersiveReader.renderButtons(options: RenderButtonsOptions); on page load as demonstrated in the below code snippet. Otherwise, the buttons will be rendered within the document's elements that have the class immersive-reader-button as shown in How-To Customize the Immersive Reader button.

// This snippet assumes there are two empty div elements in
// the page HTML, button1 and button2.
const btn1: HTMLDivElement = document.getElementById('button1');
const btn2: HTMLDivElement = document.getElementById('button2');
const btns: HTMLDivElement[] = [btn1, btn2];
ImmersiveReader.renderButtons({elements: btns});

See the above Optional Attributes for more rendering options. To use these options, add any of the option attributes to each HTMLDivElement in your page HTML.

renderButtons(options?: RenderButtonsOptions): void;

renderButtons Parameters

Name Type Description
options renderButtons options Options for configuring certain behaviors of the renderButtons function. Optional.

renderButtons Options

Options for rendering the Immersive Reader buttons.

    elements: HTMLDivElement[];

renderButtons Options Parameters

Setting Type Description
elements HTMLDivElement[] Elements to render the Immersive Reader buttons in.
Type: HTMLDivElement[]
Required: false


Contains the response from the call to ImmersiveReader.launchAsync. A reference to the HTML iframe element that contains the Immersive Reader can be accessed via container.firstChild.

    container: HTMLDivElement;
    sessionId: string;
    charactersProcessed: number;

LaunchResponse Parameters

Setting Type Description
container HTMLDivElement HTML element that contains the Immersive Reader iframe element.
sessionId String Globally unique identifier for this session, used for debugging.
charactersProcessed number Total number of characters processed


Contains information about an error.

    code: string;
    message: string;

Error Parameters

Setting Type Description
code String One of a set of error codes. For more information, see Error codes.
message String Human-readable representation of the error.

Error codes

Code Description
BadArgument Supplied argument is invalid, see message parameter of the Error.
Timeout The Immersive Reader failed to load within the specified timeout.
TokenExpired The supplied token is expired.
Throttled The call rate limit has been exceeded.



Contains the content to be shown in the Immersive Reader.

    title?: string;
    chunks: Chunk[];

Content Parameters

Name Type Description
title String Title text shown at the top of the Immersive Reader (optional)
chunks Chunk[] Array of chunks
Type: String
Required: false
Default value: "Immersive Reader" 
Type: Chunk[]
Required: true
Default value: null 


A single chunk of data, which will be passed into the Content of the Immersive Reader.

    content: string;
    lang?: string;
    mimeType?: string;

Chunk Parameters

Name Type Description
content String The string that contains the content sent to the Immersive Reader.
lang String Language of the text, the value is in IETF BCP 47-language tag format, for example, en, es-ES. Language will be detected automatically if not specified. For more information, see Supported Languages.
mimeType string Plain text, MathML, HTML & Microsoft Word DOCX formats are supported. For more information, see Supported MIME types.
Type: String
Required: true
Default value: null 
Type: String
Required: false
Default value: Automatically detected 
Type: String
Required: false
Default value: "text/plain"

Supported MIME types

MIME Type Description
text/plain Plain text.
text/html HTML content. Learn more
application/mathml+xml Mathematical Markup Language (MathML). Learn more.
application/vnd.openxmlformats-officedocument.wordprocessingml.document Microsoft Word .docx format document.


Contains properties that configure certain behaviors of the Immersive Reader.

    uiLang?: string;
    timeout?: number;
    uiZIndex?: number;
    useWebview?: boolean;
    onExit?: () => any;
    customDomain?: string;
    allowFullscreen?: boolean;
    parent?: Node; 
    hideExitButton?: boolean;
    cookiePolicy?: CookiePolicy;
    disableFirstRun?: boolean;
    readAloudOptions?: ReadAloudOptions;
    translationOptions?: TranslationOptions;
    displayOptions?: DisplayOptions;
    preferences?: string;
    onPreferencesChanged?: (value: string) => any;
    disableGrammar?: boolean;
    disableTranslation?: boolean;
    disableLanguageDetection?: boolean;

Options Parameters

Name Type Description
uiLang String Language of the UI, the value is in IETF BCP 47-language tag format, for example, en, es-ES. Defaults to browser language if not specified.
timeout Number Duration (in milliseconds) before launchAsync fails with a timeout error (default is 15,000 ms). This timeout only applies to the initial launch of the Reader page, when the Reader page opens successfully and the spinner starts. Adjustment of the timeout should'nt be necessary.
uiZIndex Number Z-index of the HTML iframe element that will be created (default is 1000).
useWebview Boolean Use a webview tag instead of an HTML iframe element, for compatibility with Chrome Apps (default is false).
onExit Function Executes when the Immersive Reader exits.
customDomain String Reserved for internal use. Custom domain where the Immersive Reader webapp is hosted (default is null).
allowFullscreen Boolean The ability to toggle fullscreen (default is true).
parent Node Node in which the HTML iframe element or Webview container is placed. If the element doesn't exist, iframe is placed in body.
hideExitButton Boolean Hides the Immersive Reader's exit button arrow (default is false). This value should only be true if there's an alternative mechanism provided to exit the Immersive Reader (e.g a mobile toolbar's back arrow).
cookiePolicy CookiePolicy Setting for the Immersive Reader's cookie usage (default is CookiePolicy.Disable). It's the responsibility of the host application to obtain any necessary user consent following EU Cookie Compliance Policy. For more information, see Cookie Policy Options.
disableFirstRun Boolean Disable the first run experience.
readAloudOptions ReadAloudOptions Options to configure Read Aloud.
translationOptions TranslationOptions Options to configure translation.
displayOptions DisplayOptions Options to configure text size, font, theme, and so on.
preferences String String returned from onPreferencesChanged representing the user's preferences in the Immersive Reader. For more information, see Settings Parameters and How-To Store User Preferences.
onPreferencesChanged Function Executes when the user's preferences have changed. For more information, see How-To Store User Preferences.
disableTranslation Boolean Disable the word and document translation experience.
disableGrammar Boolean Disable the Grammar experience. This option will also disable Syllables, Parts of Speech and Picture Dictionary, which depends on Parts of Speech.
disableLanguageDetection Boolean Disable Language Detection to ensure the Immersive Reader only uses the language that is explicitly specified on the Content/Chunk[]. This option should be used sparingly, primarily in situations where language detection isn't working, for instance, this issue is more likely to happen with short passages of fewer than 100 characters. You should be certain about the language you're sending, as text-to-speech won't have the correct voice. Syllables, Parts of Speech and Picture Dictionary won't work correctly if the language isn't correct.
Type: String
Required: false
Default value: User's browser language 
Type: Number
Required: false
Default value: 15000
Type: Number
Required: false
Default value: 1000
Type: Function
Required: false
Default value: null


IMPORTANT Do not attempt to programmatically change the values of the -preferences string sent to and from the Immersive Reader application as this may cause unexpected behavior resulting in a degraded user experience for your customers. Host applications should never assign a custom value to or manipulate the -preferences string. When using the -preferences string option, use only the exact value that was returned from the -onPreferencesChanged callback option.

Type: String
Required: false
Default value: null
Type: Function
Required: false
Default value: null
Type: String
Required: false
Default value: null


type ReadAloudOptions = {
    voice?: string;
    speed?: number;
    autoplay?: boolean;

ReadAloudOptions Parameters

Name Type Description
voice String Voice, either "Female" or "Male". Not all languages support both genders.
speed Number Playback speed, must be between 0.5 and 2.5, inclusive.
autoPlay Boolean Automatically start Read Aloud when the Immersive Reader loads.
Type: String
Required: false
Default value: "Female" or "Male" (determined by language) 
Values available: "Female", "Male"
Type: Number
Required: false
Default value: 1
Values available: 0.5, 0.75, 1, 1.25, 1.5, 1.75, 2, 2.25, 2.5


Due to browser limitations, autoplay is not supported in Safari.


type TranslationOptions = {
    language: string;
    autoEnableDocumentTranslation?: boolean;
    autoEnableWordTranslation?: boolean;

TranslationOptions Parameters

Name Type Description
language String Sets the translation language, the value is in IETF BCP 47-language tag format, for example, fr-FR, es-MX, zh-Hans-CN. Required to automatically enable word or document translation.
autoEnableDocumentTranslation Boolean Automatically translate the entire document.
autoEnableWordTranslation Boolean Automatically enable word translation.
Type: String
Required: true
Default value: null 
Values available: For more information, see the Supported Languages section


enum ThemeOption { Light, Dark }


type DisplayOptions = {
    textSize?: number;
    increaseSpacing?: boolean;
    fontFamily?: string;
    themeOption?: ThemeOption

DisplayOptions Parameters

Name Type Description
textSize Number Sets the chosen text size.
increaseSpacing Boolean Sets whether text spacing is toggled on or off.
fontFamily String Sets the chosen font ("Calibri", "ComicSans", or "Sitka").
themeOption ThemeOption Sets the chosen Theme of the reader ("Light", "Dark").
Type: Number
Required: false
Default value: 20, 36 or 42 (Determined by screen size)
Values available: 14, 20, 28, 36, 42, 48, 56, 64, 72, 84, 96
Type: String
Required: false
Default value: "Calibri"
Values available: "Calibri", "Sitka", "ComicSans"

CookiePolicy Options

enum CookiePolicy { Disable, Enable }

The settings listed below are for informational purposes only. The Immersive Reader stores its settings, or user preferences, in cookies. This cookiePolicy option disables the use of cookies by default to follow EU Cookie Compliance laws. If you want to re-enable cookies and restore the default functionality for Immersive Reader user preferences, your website or application will need proper consent from the user to enable cookies. Then, to re-enable cookies in the Immersive Reader, you must explicitly set the cookiePolicy option to CookiePolicy.Enable when launching the Immersive Reader. The table below describes what settings the Immersive Reader stores in its cookie when the cookiePolicy option is enabled.

Settings Parameters

Setting Type Description
textSize Number Sets the chosen text size.
fontFamily String Sets the chosen font ("Calibri", "ComicSans", or "Sitka").
textSpacing Number Sets whether text spacing is toggled on or off.
formattingEnabled Boolean Sets whether HTML formatting is toggled on or off.
theme String Sets the chosen theme (e.g "Light", "Dark"...).
syllabificationEnabled Boolean Sets whether syllabification toggled on or off.
nounHighlightingEnabled Boolean Sets whether noun-highlighting is toggled on or off.
nounHighlightingColor String Sets the chosen noun-highlighting color.
verbHighlightingEnabled Boolean Sets whether verb-highlighting is toggled on or off.
verbHighlightingColor String Sets the chosen verb-highlighting color.
adjectiveHighlightingEnabled Boolean Sets whether adjective-highlighting is toggled on or off.
adjectiveHighlightingColor String Sets the chosen adjective-highlighting color.
adverbHighlightingEnabled Boolean Sets whether adverb-highlighting is toggled on or off.
adverbHighlightingColor String Sets the chosen adverb-highlighting color.
pictureDictionaryEnabled Boolean Sets whether Picture Dictionary is toggled on or off.
posLabelsEnabled Boolean Sets whether the superscript text label of each highlighted Part of Speech is toggled on or off.

Supported Languages

The translation feature of Immersive Reader supports many languages. For more information, see Language Support.

HTML support

When formatting is enabled, the following content will be rendered as HTML in the Immersive Reader.

HTML Supported Content
Font Styles Bold, Italic, Underline, Code, Strikethrough, Superscript, Subscript
Unordered Lists Disc, Circle, Square
Ordered Lists Decimal, Upper-Alpha, Lower-Alpha, Upper-Roman, Lower-Roman

Unsupported tags will be rendered comparably. Images and tables are currently not supported.

Browser support

Use the most recent versions of the following browsers for the best experience with the Immersive Reader.

  • Microsoft Edge
  • Internet Explorer 11
  • Google Chrome
  • Mozilla Firefox
  • Apple Safari

Next steps