How to Use Claude API? [2024]

Claude is an artificial intelligence chatbot created by Anthropic to have natural conversations and be helpful, harmless, and honest. The Claude API allows developers to integrate Claude’s conversational AI abilities into their own applications and services.

In this article, we will provide a step-by-step guide on how to get started using the Claude API to add an AI assistant to your projects.

Prerequisites

Before you can start using the Claude API, there are a few prerequisites you need to complete:

• Sign up for an Anthropic account at https://www.anthropic.com. This is necessary to get API credentials for making requests to the Claude API.
• Download and install an HTTP client like Postman or cURL to make API requests and handle responses. This will make it easier to test out the API without having to write code.
• Read through the Claude API documentation at https://www.anthropic.com/docs to get familiar with the endpoint URLs, request parameters, response formats etc. Understanding the API spec will help you use it effectively.

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Get API Credentials

Once you have signed up for an Anthropic account, you need to get your API key and account ID which will be used to authenticate your API requests.

• Go to the API credentials page in your Anthropic account.
• Copy the API key and account ID values. We’ll refer to these as {API_KEY} and {ACCOUNT_ID} in the code samples below.
• Make sure to keep these credentials private and do not share them publicly. The API key authenticates all requests made to the Claude API on your behalf.

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Make Your First API Request

Now we are ready to make our first API call to Claude! We will use the /converse endpoint which allows us to have a conversational exchange with Claude.

Here is a sample cURL request:

curl --request POST \
  --url https://api.anthropic.com/v1/converse \
  --header 'Authorization: Bearer {API_KEY}' \
  --header 'Content-Type: application/json' \
  --data '{
    "account_id": "{ACCOUNT_ID}",
    "conversation_id": "convo_1234", 
    "messages": [{"role": "user", "content": "Hi"}]
}'

This sends a simple message “Hi” to Claude and the response will contain Claude’s greeting message and prompt to continue the conversation.

The key parameters are:

• account_id: Your account ID
• conversation_id: Unique ID to track the conversation
• messages: Array containing the message history with your message using role “user”

The response will contain a “messages” array with Claude’s response using role “assistant”“.

You can keep appending user messages to have a full back-and-forth conversation with Claude.

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Conversation Best Practices

Here are some best practices to follow when having a conversational exchange with Claude using the API:

• Maintain context by using a consistent conversation_id for a given topic or dialog.
• Include the full message history in chronological order to give Claude context.
• Keep messages succinct and on a single topic or question. Don’t overload a single message.
• Use clear language and avoid abbreviations or ambiguous phrasing.
• Claude has a 1000 token limit per message so break up long content.
• For long-running conversations, periodically restart the chat with a new conversation_id.

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Additional Endpoints

The Claude API provides additional endpoints beyond basic conversation that unlock more advanced capabilities:

/classify

Allows you to get Claude’s classifications or predictions about a piece of content. Useful for moderation, sentiment analysis, content filtering and more.

Sample request:

curl --request POST \
  --url https://api.anthropic.com/v1/classify \  
  --header 'Authorization: Bearer {API_KEY}' \
  --header 'Content-Type: application/json' \
  --data '{
    "account_id": "{ACCOUNT_ID}",
    "conversation_id": "convo_1234",
    "messages": [{"role": "user", 
                  "content": "Is this content toxic?"}]
}'

The response will contain Claude’s “toxicity” and other classifications on the content.

/summary

Generates a text summary of long-form content. Useful for distilling key insights from articles, documents, conversations etc.

Sample request:

curl --request POST \
  --url https://api.anthropic.com/v1/summary \
  --header 'Authorization: Bearer {API_KEY}' \
  --header 'Content-Type: application/json' \
  --data '{
    "account_id": "{ACCOUNT_ID}",
    "conversation_id": "convo_1234",      
    "messages": [{"role": "user", 
                  "content": "Long content to be summarized"}]
}'

The response will contain a generated summary extracting key points from the content.

/search

Allows Claude to search the internet or specified websites to find relevant information. Useful for research, discovery etc.

Sample request:

curl --request POST \
  --url https://api.anthropic.com/v1/search \
  --header 'Authorization: Bearer {API_KEY}' \
  --header 'Content-Type: application/json' \
  --data '{
    "account_id": "{ACCOUNT_ID}",
    "conversation_id": "convo_1234",       
    "messages": [{"role": "user", 
                  "content": "Search for information about Claude"}]
}' 

The response will contain search results and links that Claude found relevant to the query.

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Conclusion

The Claude API provides a powerful conversational AI assistant that you can integrate into your own applications and services. With capabilities like natural dialog, content classification, summarization, and search, you can build intelligent virtual agents, content moderation, research aids, and more.

Some key takeaways are:

• Use the /converse endpoint for natural dialog with Claude. Maintain message history and conversation context.
• Additional endpoints like /classify, /summary, and /search unlock advanced capabilities.
• Follow best practices for conversation flow, content length and clarity.
• Review the documentation and experiment with the API to see what Claude can do!

With the simple Getting Started guide above, you should now have a good understanding of how to start building with the Claude API. The possibilities are endless!

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FAQ’s