Summarizer: summarizeStreaming() method

Limited availability

This feature is not Baseline because it does not work in some of the most widely-used browsers.

See full compatibility

Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.

The summarizeStreaming() method of the Summarizer interface generates a new summary as a ReadableStream.

Syntax

summarizeStreaming(input)
summarizeStreaming(input, options)

Parameters

input

A string representing the text to be summarized.

options Optional

An object specifying configuration options for the summarizeStreaming() operation. Possible values include:

context: A string describing the context the input text is being used in, which helps the Summarizer generate a more suitable summary.
signal: An AbortSignal object instance, which allows the summarizeStreaming() operation to be aborted via the associated AbortController.

Return value

A ReadableStream containing the generated summary.

Exceptions

AbortError DOMException: Thrown if the Summarizer was previously destroyed (had Summarizer.destroy() called on it, or was aborted via its abort signal after creation).
InvalidStateError DOMException: Thrown if the current Document is not active.
NotAllowedError DOMException: Thrown if usage of the Summarizer API is blocked by a summarizer Permissions-Policy.
NotReadableError DOMException: Thrown if the output summary was filtered by the user agent, for example because it was detected to be harmful, inaccurate, or nonsensical.
NotSupportedError DOMException: Thrown if the provided context is not in language the Summarizer supports.
QuotaExceededError: Thrown if the summarize operation exceeds the available inputQuota.
UnknownError DOMException: Thrown if the summarizeStreaming() call failed for any other reason, or a reason the user agent did not wish to disclose.

Examples

Basic `summarizeStreaming()` usage

const summarizer = await Summarizer.create({
  sharedContext:
    "A general summary to help a user decide if the text is worth reading",
  type: "tldr",
  length: "short",
});

const stream = summarizer.summarizeStreaming(myTextString);
let summary = "";

for await (const chunk of stream) {
  summary += chunk;
}

console.log("Stream complete");
summaryOutput.textContent = summary;

Specifications

Specification
Writing Assistance APIs # dom-summarizer-summarizestreaming

Browser compatibility

	desktop					mobile							server
	Chrome	Edge	Firefox	Opera	Safari	Chrome Android	Firefox for Android	Opera Android	Safari on iOS	Samsung Internet	WebView Android	WebView on iOS	Deno	Node.js
`summarizeStreaming()` instance method Experimental	Chrome – Full support Chrome 138 (Release date: 2025-06-24) footnote footnote Availability may be subject to geographical restrictions.	Edge – No support Edge 138 (Release date: 2025-06-26) disabled disabled From version 138 users must explicitly set the `#edge-llm-summarization-api-for-phi-mini` preference to `Enabled`. To change preferences in Edge, visit about:flags.	Firefox – No support Firefox footnote No support	Opera – Full support Opera 122 (Release date: 2025-09-11) footnote footnote Availability may be subject to geographical restrictions.	Safari – No support Safari footnote No support	Chrome Android – No support Chrome Android footnote No support	Firefox for Android – No support Firefox for Android footnote No support	Opera Android – No support Opera Android footnote No support	Safari on iOS – No support Safari on iOS footnote No support	Samsung Internet – No support Samsung Internet footnote No support	WebView Android – No support WebView Android footnote No support	WebView on iOS – No support WebView on iOS footnote No support	Deno – No support Deno footnote No support	Node.js – No support Node.js footnote No support

Tip: you can click/tap on a cell for more information.

Full support: Full support
No support: No support
: Experimental. Expect behavior to change in the future.
: See implementation notes.
: User must explicitly enable this feature.

Summarizer: summarizeStreaming() method

Legend