Summarizer: summarizeStreaming() method

Limited availability

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

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

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

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This page was last modified on ⁨Aug 19, 2025⁩ by MDN contributors.

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