Principle:Langchain ai Langchain Streaming Method Invocation

Knowledge Sources	LangChain
Domains	Streaming, NLP
Last Updated	2026-02-11 00:00 GMT

Overview

The public API for streaming chat model responses as an iterator of incremental message chunks.

Description

Streaming method invocation provides the user-facing stream() and astream() methods that return iterators of AIMessageChunk objects. Each chunk contains a portion of the model's response (a few tokens). The methods handle callback setup, delegate to the provider's _stream() or _astream() implementation, and manage error handling and cleanup.

Usage

Use stream() for synchronous streaming and astream() for async streaming. Iterate over the result to process chunks incrementally.

Theoretical Basis

# Abstract streaming pattern (not real code)
for chunk in model.stream(input):
    display(chunk.content)  # Progressive display
    accumulated += chunk    # Accumulate if needed

Related Pages

Implemented By

• Implementation:Langchain_ai_Langchain_BaseChatModel_Stream