Types Overview

Core type system for the Google Gen AI SDK

Overview

The types module provides the core type system for the Google Gen AI SDK. It includes Pydantic models and TypedDict definitions for all API request and response objects.

Importing Types

Types can be imported directly from the main package:

from google import genai
from google.genai import types

# Import specific types
from google.genai.types import (
    Part,
    Content,
    GenerateContentConfig,
    HttpOptions,
)

Pydantic Models vs TypedDict

The SDK provides two ways to work with types:

Pydantic Models

Pydantic models provide validation, type checking, and convenient methods:

from google.genai.types import Part, Content

# Create using Pydantic model
part = Part.from_text(text="Hello")
content = Content(parts=[part], role="user")

Benefits:

• Runtime validation
• Type safety
• Helper methods and constructors
• Serialization/deserialization

TypedDict

TypedDict definitions provide type hints for dictionaries:

from google.genai.types import PartDict, ContentDict

# Create using plain dict
part_dict: PartDict = {"text": "Hello"}
content_dict: ContentDict = {
    "parts": [part_dict],
    "role": "user"
}

Benefits:

• Lighter weight
• More flexible
• Compatible with JSON serialization
• Editor autocomplete

Union Types

Many parameters accept union types for flexibility:

from google.genai.types import PartOrDict, ContentOrDict

# These are equivalent
PartOrDict = Union[Part, PartDict]
ContentOrDict = Union[Content, ContentDict]

Key Type Categories

Content Types

Types for representing messages and content:

• Content - Multi-part message content
• Part - Individual content parts
• UserContent - Content from the user
• ModelContent - Content from the model

Configuration Types

Types for configuring API requests:

• GenerateContentConfig - Content generation parameters
• HttpOptions - HTTP request options
• HttpRetryOptions - Retry configuration

Enum Types

The module includes many enum types for API options:

from google.genai.types import (
    HarmCategory,
    HarmBlockThreshold,
    FinishReason,
    FunctionCallingConfigMode,
)

All enums are case-insensitive:

# These are equivalent
HarmBlockThreshold.BLOCK_MEDIUM_AND_ABOVE
HarmBlockThreshold.block_medium_and_above

Type Hierarchy

Content
├── UserContent (role="user")
├── ModelContent (role="model")
└── parts: List[Part]
    ├── text: str
    ├── inline_data: Blob
    ├── file_data: FileData
    ├── function_call: FunctionCall
    ├── function_response: FunctionResponse
    ├── executable_code: ExecutableCode
    └── code_execution_result: CodeExecutionResult

Common Patterns

Creating Content

from google.genai.types import UserContent, Part

# Simple text
content = UserContent("Hello, world!")

# Multiple parts
content = UserContent([
    "What's in this image?",
    Part.from_uri(file_uri="gs://bucket/image.jpg", mime_type="image/jpeg")
])

# Mixed content
content = UserContent([
    Part.from_text(text="Analyze this:"),
    Part.from_bytes(data=image_bytes, mime_type="image/png")
])

Using Configuration

from google.genai.types import GenerateContentConfig

config = GenerateContentConfig(
    temperature=0.7,
    max_output_tokens=1024,
    top_p=0.95,
    response_mime_type="application/json"
)

response = client.models.generate_content(
    model="gemini-2.0-flash",
    contents="Tell me a story",
    config=config
)

See Also

• Content Types - Detailed content type reference
• Part Class - Part factory methods
• Configuration Types - Configuration options
• Client Reference - Using types with the client