ConverseStream API availability

The ConverseStream API in Amazon Bedrock is available for multiple models, not just Anthropic Claude. According to the documentation, Amazon Titan models do support the ConverseStream API.

Specifically, the Converse API supports various Amazon Bedrock models with streaming capabilities, including:

• Amazon Titan models (support both Converse and ConverseStream)
• Anthropic Claude 2.x and earlier models
• Anthropic Claude 3 models
• Anthropic Claude 3.5 Sonnet, Sonnet v2
• Anthropic Claude 3.7 Sonnet
• Anthropic Claude 3.5 Haiku

So yes, you can use the ConverseStream API with Amazon Titan Text Express LLM. The ConverseStream API provides a consistent interface for all Amazon Bedrock models that support messages, allowing you to write code once and use it with different models.

Note that while the API is available for these models, some specific features (like vision capabilities, tool use, etc.) may vary between models. For example, Amazon Titan models support document chat (except for Titan Text Premier) but don't support system prompts, vision, or tool use features.
Sources
Supported models and model features - Amazon Bedrock
ConverseStream - Amazon Bedrock