Managed Inference and Agents API with Claude 4.5 Haiku

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When to Use This Model
Usage

Last updated October 24, 2025

Claude 4.5 Haiku is a large language model (LLM) in Anthropic’s Claude family that supports conversational chat, tool-calling, and enhanced reasoning for complex tasks with extended thinking. It offers a fast, intelligent, and cost-effective solution you can use to power your AI applications.

Model ID: claude-4-5-haiku
Region: us, eu

When to Use This Model

Claude 4.5 Haiku supports a variety of common use cases, including rapid responses, content moderation, and inventory management. It’s optimized for high-throughput tasks and real-time interactions.

Usage

Claude 4.5 Haiku follows our Claude v1/chat/completions API schema.

To provision access to the model, attach claude-4-5-haiku to your app $APP_NAME:

heroku ai:models:create -a $APP_NAME claude-4-5-haiku

Using config variables, you can invoke claude-4-5-haiku in a variety of ways:

Heroku CLI ai plugin (heroku ai:models:call)
curl
Python
Ruby
Javascript

Rate Limits

Maximum requests per minute: 200
Maximum tokens per minute: 800,000

Example curl Request

Get started quickly with an example request:

export INFERENCE_MODEL_ID=$(heroku config:get -a $APP_NAME INFERENCE_MODEL_ID)
export INFERENCE_KEY=$(heroku config:get -a $APP_NAME INFERENCE_KEY)
export INFERENCE_URL=$(heroku config:get -a $APP_NAME INFERENCE_URL)

curl $INFERENCE_URL/v1/chat/completions \
-H "Authorization: Bearer $INFERENCE_KEY" \
-d @- <<EOF
{
  "model": "$INFERENCE_MODEL_ID",
  "messages": [
    { "role": "user", "content": "Hello!" },
    { "role": "assistant", "content": "Hi there! How can I assist you today?" },
    { "role": "user", "content": "What's the weather like in Portland, Oregon right now?" }
  ],
  "temperature": 0.5,
  "max_tokens": 100,
  "stream": false,
  "tools": [
    {
      "type": "function",
      "function": {
        "name": "get_weather",
        "description": "Fetches the current weather for a given city.",
        "parameters": {
          "type": "object",
          "properties": {
            "city": {
              "type": "string",
              "description": "The name of the city to get weather for."
            }
          },
          "required": ["city"]
        }
      }
    }
  ],
  "tool_choice": "auto",
  "top_p": 0.9
}
EOF

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