# Using the Invoke API
<a name="using-invoke-api"></a>

 The Invoke API provides direct access to Amazon Nova models with more ability to control the request and response format. Unlike the Converse API which abstracts model-specific details, the Invoke API allows you to work directly with the model's native request and response structures. 

**Note**  
The Invoke API supports the same features as the Converse API except for document input modality, which is specific to the Converse API.

## Request structure
<a name="invoke-api-request"></a>

An Invoke API request requires the model ID and a JSON request body:

```
import boto3
import json

bedrock = boto3.client('bedrock-runtime', region_name='us-east-1')

request_body = {
    'messages': [
        {
            'role': 'user',
            'content': [{'text': 'What is machine learning?'}]
        }
    ],
    'inferenceConfig': {
        'maxTokens': 512,
        'temperature': 0.7
    }
}

response = bedrock.invoke_model(
    modelId='us.amazon.nova-2-lite-v1:0',
    body=json.dumps(request_body)
)

response_body = json.loads(response['body'].read())
content_list = response_body["output"]["message"]["content"]
# Extract the first text block
text_block = next((item for item in content_list if "text" in item), None)
if text_block is not None:
    print(text_block["text"])
```

## Request parameters
<a name="invoke-api-parameters"></a>

The Invoke API supports the following key parameters:
+ `messages`: Array of conversation messages with role and content
+ `system`: Optional system prompt for context and instructions
+ `inferenceConfig`: Parameters controlling model output (temperature, maxTokens, topP, topK, stopSequences, reasoningConfig)
+ `toolConfig`: Tool specifications and tool choice for function calling