Models/Claude Opus 4

Claude Opus 4

claude-opus-4-20250514

Most capable model with superior reasoning and analysis capabilities.

Most CapableSuperior ReasoningComplex Tasks

Input¥36.75

Output¥183.75

per 1M tokens

Most Capable

Top-tier intelligence

Superior Reasoning

Best-in-class logic

Complex Tasks

Handle any challenge

Premium Quality

Highest output quality

API Documentation

View complete API reference with all parameters and examples.

View Docs

Advanced Features

Streaming

Enable real-time streaming responses with Server-Sent Events.

{
  "model": "claude-opus-4-20250514",
  "stream": true,
  "max_tokens": 1024,
  "messages": [...]
}

Function Calling (Tools)

Enable Claude to use tools and call functions.

{
  "model": "claude-opus-4-20250514",
  "max_tokens": 1024,
  "tools": [{
    "name": "get_weather",
    "description": "Get current weather for a location",
    "input_schema": {
      "type": "object",
      "properties": {
        "location": {"type": "string", "description": "City name"}
      },
      "required": ["location"]
    }
  }],
  "tool_choice": {"type": "auto"},
  "messages": [{"role": "user", "content": "What's the weather in Tokyo?"}]
}

PDF Support

Analyze PDF documents by sending them as base64 encoded content.

{
  "model": "claude-opus-4-20250514",
  "max_tokens": 1024,
  "messages": [{
    "role": "user",
    "content": [{
      "type": "document",
      "source": {
        "type": "base64",
        "media_type": "application/pdf",
        "data": "<base64_encoded_pdf>"
      }
    }, {
      "type": "text",
      "text": "Summarize this document."
    }]
  }]
}

Structured Output (JSON Schema)

Get structured JSON responses that match your schema.

{
  "model": "claude-opus-4-20250514",
  "max_tokens": 1024,
  "output_format": {
    "type": "json_schema",
    "schema": {
      "type": "object",
      "properties": {
        "name": {"type": "string"},
        "age": {"type": "integer"}
      },
      "required": ["name", "age"]
    }
  },
  "messages": [{"role": "user", "content": "Extract info: John is 30 years old"}]
}

Web Search

Enable Claude to search the web for up-to-date information.

{
  "model": "claude-opus-4-20250514",
  "max_tokens": 1024,
  "tools": [{
    "type": "web_search_20250305",
    "name": "web_search",
    "max_uses": 5
  }],
  "messages": [{"role": "user", "content": "What's the latest news about AI?"}]
}

API Parameters Reference

Parameter	Type	Required	Description
model	string	Yes	Model identifier (e.g., claude-opus-4-20250514)
messages	array	Yes	Array of message objects with role and content
max_tokens	integer	Yes	Maximum tokens in the response (1 - 128000)
system	string	No	System prompt to set context
stream	boolean	No	Enable streaming responses (SSE)
temperature	number	No	Sampling temperature (0.0 - 1.0)
top_p	number	No	Nucleus sampling threshold (0.0 - 1.0)
top_k	integer	No	Top-k sampling (0 - infinity)
stop_sequences	array	No	Sequences that stop generation
tools	array	No	Function calling tools definition
tool_choice	object	No	Tool selection strategy (auto/any/tool)
thinking	object	No	Enable extended thinking mode
output_format	object	No	Structured output with JSON schema

Full API Documentation

View complete API reference with streaming, thinking, and more.

View Documentation

Pricing

Input

¥36.75

per 1M tokens

Output

¥183.75

per 1M tokens

Billing: Cost = (input_tokens * input_price + output_tokens * output_price) / 1,000,000