> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/googleapis/python-genai/llms.txt
> Use this file to discover all available pages before exploring further.

# 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:

```python theme={null}
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:

```python theme={null}
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:

```python theme={null}
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:

```python theme={null}
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](/api/types/content) - Multi-part message content
* [Part](/api/types/part) - Individual content parts
* UserContent - Content from the user
* ModelContent - Content from the model

### Configuration Types

Types for configuring API requests:

* [GenerateContentConfig](/api/types/config#generatecontentconfig) - Content generation parameters
* [HttpOptions](/api/types/config#httpoptions) - HTTP request options
* [HttpRetryOptions](/api/types/config#httpretryoptions) - Retry configuration

### Enum Types

The module includes many enum types for API options:

```python theme={null}
from google.genai.types import (
    HarmCategory,
    HarmBlockThreshold,
    FinishReason,
    FunctionCallingConfigMode,
)
```

All enums are case-insensitive:

```python theme={null}
# 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

```python theme={null}
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

```python theme={null}
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](/api/types/content) - Detailed content type reference
* [Part Class](/api/types/part) - Part factory methods
* [Configuration Types](/api/types/config) - Configuration options
* [Client Reference](/api/client) - Using types with the client