chat.send_message

Send messages in a chat session with streaming support

Sends a message in the chat session and receives the model’s response. The chat maintains conversation history automatically.

Method Signatures

send_message (Non-streaming)

chat.send_message(
    message: Union[list[PartUnionDict], PartUnionDict],
    config: Optional[GenerateContentConfigOrDict] = None
) -> GenerateContentResponse

send_message_stream (Streaming)

chat.send_message_stream(
    message: Union[list[PartUnionDict], PartUnionDict],
    config: Optional[GenerateContentConfigOrDict] = None
) -> Iterator[GenerateContentResponse]

Parameters

message · string | Part | list[Part] · required

The message to send to the model.

Can be:

• A simple string: "Tell me a story"
• A Part object: Part(text="Hello")
• A list of Parts: [Part(text="Describe this:"), Part(inline_data=image)]

Supported part types:

• Text
• Images (PIL Image, bytes, or file data)
• Video
• Audio
• File references

config · GenerateContentConfig

Optional configuration to override the chat’s default config for this specific request.

Common options:

• temperature: Controls randomness
• max_output_tokens: Maximum response length
• top_p, top_k: Sampling parameters
• response_mime_type: Output format (e.g., "application/json")

Returns

send_message

response · GenerateContentResponse

The complete model response containing:

• text: The response text
• candidates: List of response candidates
• usage_metadata: Token usage information
• model_version: The model version used

send_message_stream

chunks · Iterator[GenerateContentResponse]

An iterator that yields response chunks as they’re generated.

Each chunk contains partial content that can be displayed incrementally.

Examples

Basic Text Message

from google import genai

client = genai.Client(api_key='your-api-key')

# Create chat
chat = client.chats.create(model='gemini-2.0-flash')

# Send message
response = chat.send_message('Tell me a story about a robot')
print(response.text)

Streaming Response

# Create chat
chat = client.chats.create(model='gemini-2.0-flash')

# Stream the response
for chunk in chat.send_message_stream('Write a poem about the ocean'):
    print(chunk.text, end='')
print()  # New line after streaming completes

Message with Image

from google.genai import types
from PIL import Image

# Load image
image = Image.open('photo.jpg')

# Create chat
chat = client.chats.create(model='gemini-2.0-flash')

# Send message with image
response = chat.send_message([
    'What do you see in this image?',
    image
])
print(response.text)

Override Configuration

# Create chat with default config
chat = client.chats.create(
    model='gemini-2.0-flash',
    config={'temperature': 0.5}
)

# Override config for a specific message
response = chat.send_message(
    'Be creative and write a story',
    config={'temperature': 1.5}  # More creative for this message
)
print(response.text)

Multi-turn Conversation

# Create chat
chat = client.chats.create(model='gemini-2.0-flash')

# First turn
response = chat.send_message('What is the capital of France?')
print(f"Assistant: {response.text}")

# Second turn - chat remembers context
response = chat.send_message('What is its population?')
print(f"Assistant: {response.text}")

# Third turn
response = chat.send_message('What are some famous landmarks there?')
print(f"Assistant: {response.text}")

JSON Output

import json

chat = client.chats.create(model='gemini-2.0-flash')

response = chat.send_message(
    'List 3 colors with their hex codes',
    config={'response_mime_type': 'application/json'}
)

colors = json.loads(response.text)
print(colors)

Async Streaming

import asyncio
from google import genai

client = genai.Client(api_key='your-api-key')

async def stream_example():
    # Create async chat
    chat = client.aio.chats.create(model='gemini-2.0-flash')
    
    # Stream response asynchronously
    async for chunk in await chat.send_message_stream('Tell me a story'):
        print(chunk.text, end='')
    print()

asyncio.run(stream_example())

File Upload in Chat

# Upload a file first
file = client.files.upload(file='document.pdf')

# Use in chat
chat = client.chats.create(model='gemini-2.0-flash')
response = chat.send_message([
    types.Part(file_data=types.FileData(file_uri=file.uri)),
    'Summarize this document'
])
print(response.text)

Access Chat History

chat = client.chats.create(model='gemini-2.0-flash')

# Send some messages
chat.send_message('Hello')
chat.send_message('How are you?')

# Get comprehensive history (includes all turns)
history = chat.get_history(curated=False)
for content in history:
    print(f"{content.role}: {content.parts[0].text}")

# Get curated history (only valid turns)
curated_history = chat.get_history(curated=True)

Error Handling

try:
    chat = client.chats.create(model='gemini-2.0-flash')
    response = chat.send_message('Hello')
    print(response.text)
except Exception as e:
    print(f"Error: {e}")

API Availability

These methods are available in both Gemini API and Vertex AI.

Related Methods

• chats.create - Create a new chat session
• models.generate_content - Single-turn generation