smoothStream()

smoothStream is a utility function that creates a TransformStream for the streamText transform option to smooth out text streaming by buffering and releasing complete words with configurable delays. This creates a more natural reading experience when streaming text responses.

import { smoothStream, streamText } from 'ai';

const result = streamText({
  model,
  prompt,
  experimental_transform: smoothStream({
    delayInMs: 20, // optional: defaults to 10ms
  }),
});

Import

import { smoothStream } from "ai"

API Signature

Parameters

Returns

Returns a TransformStream that:

• Buffers incoming text chunks
• Releases complete words when whitespace is encountered
• Adds configurable delays between words for smooth output
• Passes through non-text chunks (like step-finish events) immediately