Anthropic API - Claude Safe and Reliable AI API Service

📋 Service Overview

Service Name: Anthropic API
Provider: Anthropic
API Endpoint: https://api.anthropic.com/v1
Service Type: Prepaid (minimum $5 top-up, new users may receive trial credits)
Registration Required: Yes, account registration and credit purchase required

✅ Service Description

Anthropic API is a developer API service provided by Anthropic, allowing developers to integrate Claude models into their applications. The API uses a prepaid model, supports multiple Claude models, and is renowned for its powerful reasoning capabilities, ultra-long context, and AI safety.

Main Features

• Ultra-Long Context: Standard 200K tokens, select models support 1M (beta)
• Powerful Reasoning: Excellent performance in complex reasoning, code generation, logical analysis
• AI Safety: Focused on providing safe and reliable AI services, reducing harmful content generation
• Flexible Pricing: Pay-as-you-go, different models at different prices

🎁 Available Models

Free/Trial Model List

Note: Need to purchase usage credits in advance, minimum $5 top-up. Researchers can apply for AI for Science Program for free credits.

Model Details

Claude 3.5 Sonnet (Recommended)

• Context Window: 200,000 tokens (select versions support 1M beta)
• Main Use: General conversation, complex reasoning, code generation
• Advantages: Best balance of performance and cost, excellent in multiple benchmarks
• Update: Released October 2024 with significant performance improvements

Claude 3 Opus

• Context Window: 200,000 tokens
• Main Use: Most complex tasks, deep analysis, high precision requirements
• Advantages: Strongest performance in Claude 3 series, highest intelligence
• Suitable For: Scenarios with extremely high accuracy and intelligence requirements

Claude 3 Haiku

• Context Window: 200,000 tokens
• Main Use: Daily conversation, simple tasks, high-frequency calls
• Advantages: Fast response, lowest price, best cost-effectiveness
• Suitable For: Cost-sensitive large-scale deployments

🔢 Quota and Limits

Prepaid Model

⚠️ Important Limitations

1. Prepaid Requirement: Need to purchase usage credits (new users may receive trial credits in console)
2. Credit Expiration: Purchased credits expire after 1 year and are non-refundable
3. Rate Limits: New accounts have rate limits, automatically upgrade tier based on cumulative spending
4. Regional Restrictions: Some regions may not have direct API access
5. Research Grants: Researchers can apply for AI for Science for free credits

Rate Limit Examples

Note: RPM = Requests Per Minute, TPM = Tokens Per Minute

💰 Pricing

Pricing Table

Cost Estimation Examples

Example 1: Simple Conversation

• Input: 1,000 tokens (~750 words)
• Output: 500 tokens (~375 words)
• Model: Claude 3.5 Sonnet
• Cost: (1,000 × $3 + 500 × $15) / 1,000,000 = $0.0105

Example 2: Long Document Analysis

• Input: 50,000 tokens (~37,500 words)
• Output: 2,000 tokens (~1,500 words)
• Model: Claude 3.5 Sonnet
• Cost: (50,000 × $3 + 2,000 × $15) / 1,000,000 = $0.18

Example 3: High-Frequency Simple Tasks

• Per call input: 500 tokens
• Per call output: 200 tokens
• Daily calls: 1,000
• Model: Claude 3 Haiku
• Daily cost: (500 × 1,000 × $0.25 + 200 × 1,000 × $1.25) / 1,000,000 = $0.375

🚀 How to Use

Prerequisites

1. Register Account

Please register an account first:

• Visit https://console.anthropic.com
• Register with Google account or email
• Verify email

2. Purchase Usage Credits

💻 Code Examples

Python Example

Install Dependencies:

pip install anthropic

Basic Usage:

import anthropic

# Initialize client (replace with your API key)
client = anthropic.Anthropic(
    api_key="your-api-key-here"
)

# Send request
response = client.messages.create(
    model="claude-3-5-sonnet-20241022",
    max_tokens=1024,
    messages=[
        {
            "role": "user",
            "content": "Hello, please introduce the main features of Claude API."
        }
    ]
)

# Print response
print(response.content[0].text)

# View token usage
print(f"\nInput Tokens: {response.usage.input_tokens}")
print(f"Output Tokens: {response.usage.output_tokens}")

Using System Prompt:

response = client.messages.create(
    model="claude-3-5-sonnet-20241022",
    max_tokens=2048,
    system="You are a professional Python programming assistant, skilled at code optimization and best practices.",
    messages=[
        {
            "role": "user",
            "content": "Please optimize this code:\n\n```python\ndef find_max(arr):\n    max_val = arr[0]\n    for i in range(len(arr)):\n        if arr[i] > max_val:\n            max_val = arr[i]\n    return max_val\n```"
        }
    ]
)

print(response.content[0].text)

Streaming Example:

# Streaming output (suitable for real-time display)
with client.messages.stream(
    model="claude-3-5-sonnet-20241022",
    max_tokens=1024,
    messages=[
        {
            "role": "user",
            "content": "Write a poem about AI"
        }
    ]
) as stream:
    for text in stream.text_stream:
        print(text, end="", flush=True)

cURL Example

Basic Request:

curl https://api.anthropic.com/v1/messages \
  -H "Content-Type: application/json" \
  -H "x-api-key: your-api-key-here" \
  -H "anthropic-version: 2023-06-01" \
  -d '{
    "model": "claude-3-5-sonnet-20241022",
    "max_tokens": 1024,
    "messages": [
      {
        "role": "user",
        "content": "Hello, please introduce Claude API."
      }
    ]
  }'

With System Prompt:

curl https://api.anthropic.com/v1/messages \
  -H "Content-Type: application/json" \
  -H "x-api-key: your-api-key-here" \
  -H "anthropic-version: 2023-06-01" \
  -d '{
    "model": "claude-3-5-sonnet-20241022",
    "max_tokens": 1024,
    "system": "You are a professional technical consultant.",
    "messages": [
      {
        "role": "user",
        "content": "What is microservices architecture?"
      }
    ]
  }'

Node.js Example

import Anthropic from '@anthropic-ai/sdk';

const client = new Anthropic({
  apiKey: 'your-api-key-here',
});

async function main() {
  const message = await client.messages.create({
    model: 'claude-3-5-sonnet-20241022',
    max_tokens: 1024,
    messages: [
      {
        role: 'user',
        content: 'Hello, please introduce the main features of Claude API.'
      }
    ],
  });

  console.log(message.content[0].text);
  console.log(`\nInput Tokens: ${message.usage.input_tokens}`);
  console.log(`Output Tokens: ${message.usage.output_tokens}`);
}

main();

🌟 Core Advantages

Technical Advantages

1. Ultra-Long Context Processing:

   • 200K tokens context window
   • Can process ~150,000 words of text
   • Suitable for long document analysis and complex conversations
   • Supports complete codebase understanding

2. Powerful Reasoning Capability:

   • Complex logical reasoning
   • Multi-step problem solving
   • Code generation and analysis
   • Mathematical and scientific computation

3. AI Safety Guarantee:

   • Reduced harmful content generation
   • Lower hallucination probability
   • More accurate and reliable output
   • Meets enterprise-grade safety requirements

Comparison with Other APIs

💡 Practical Recommendations

✅ Recommended Practices

1. Choose Right Model:

   • Use Haiku for simple tasks (low cost)
   • Use 3.5 Sonnet for general tasks (balanced)
   • Use Opus for complex tasks (highest performance)

2. Optimize Token Usage:

   • Streamline input text, remove redundancy
   • Use clear and concise prompts
   • Set reasonable max_tokens limits
   • Use system prompts for persistent instructions

3. Fully Utilize Long Context:

   # Pass complete document at once
   with open("long_document.txt", "r") as f:
       document = f.read()
   
   response = client.messages.create(
       model="claude-3-5-sonnet-20241022",
       max_tokens=2048,
       messages=[
           {
               "role": "user",
               "content": f"Please analyze the following document:\n\n{document}\n\nSummarize main points."
           }
       ]
   )

🎯 Best Practices

Error Handling and Retry:

import time
from anthropic import Anthropic, APIError, RateLimitError

client = Anthropic(api_key="your-api-key-here")

def call_api_with_retry(messages, max_retries=3):
    """API call with retry mechanism"""
    for attempt in range(max_retries):
        try:
            response = client.messages.create(
                model="claude-3-5-sonnet-20241022",
                max_tokens=1024,
                messages=messages
            )
            return response
        except RateLimitError:
            wait_time = 2 ** attempt
            print(f"Rate limit reached, waiting {wait_time} seconds...")
            time.sleep(wait_time)
        except APIError as e:
            print(f"API error: {e}")
            if attempt == max_retries - 1:
                raise
    
    return None

# Usage example
messages = [{"role": "user", "content": "Hello"}]
response = call_api_with_retry(messages)
if response:
    print(response.content[0].text)

Cost Monitoring:

def calculate_cost(input_tokens, output_tokens, model="claude-3-5-sonnet"):
    """Calculate API call cost"""
    pricing = {
        "claude-3-5-sonnet": {"input": 3, "output": 15},
        "claude-3-opus": {"input": 15, "output": 75},
        "claude-3-haiku": {"input": 0.25, "output": 1.25}
    }
    
    price = pricing.get(model, pricing["claude-3-5-sonnet"])
    cost = (input_tokens * price["input"] + output_tokens * price["output"]) / 1_000_000
    
    return cost

# Usage example
response = client.messages.create(
    model="claude-3-5-sonnet-20241022",
    max_tokens=1024,
    messages=[{"role": "user", "content": "Hello"}]
)

cost = calculate_cost(
    response.usage.input_tokens,
    response.usage.output_tokens
)
print(f"Cost for this call: ${cost:.6f}")

⚠️ Precautions

1. API Key Security: Don’t hardcode API keys, use environment variables
2. Rate Limits: New accounts have strict limits, need to build usage history
3. Cost Control: Monitor usage to avoid unexpected high bills
4. Regional Restrictions: Some regions may require special network environment

🔧 Common Questions

Q: How to get API key?
A: Log in to https://console.anthropic.com, create new key in “API Keys” page.

Q: What’s the minimum top-up amount?
A: Minimum top-up is $5, purchased credits valid for 1 year.

Q: Is there free trial credit?
A: General users need to purchase credits. Researchers can apply for AI for Science Program for free credits (up to $20,000).

Q: Does API support streaming?
A: Yes, Anthropic API supports streaming output (Server-Sent Events), suitable for real-time display.

Q: How to handle rate limits?
A: Implement exponential backoff retry, or contact Anthropic to increase limits.

Q: Is API compatible with OpenAI?
A: Not fully compatible, but API design is similar. Use Anthropic official SDK or refer to API documentation.

🔗 Related Resources

• API Endpoint: https://api.anthropic.com/v1
• Developer Console: https://console.anthropic.com
• API Documentation: https://docs.anthropic.com
• Pricing Information: https://www.anthropic.com/pricing
• Provider Homepage: Anthropic
• Corresponding Chatbot Service: Claude Chatbot
• Python SDK: https://github.com/anthropics/anthropic-sdk-python
• TypeScript SDK: https://github.com/anthropics/anthropic-sdk-typescript
• API Status: https://status.anthropic.com

📝 Changelog

• October 2024: Launched Claude 3.5 Sonnet with significant performance improvements
• March 2024: Released Claude 3 series API
• 2023: Claude 2 API with 100K context support
• 2022: Claude API officially released

Service Provider: Anthropic