How to Use Claude API Python? [2023]

How to Use Claude API Python? The Claude API allows developers to integrate powerful AI capabilities into their applications using simple API calls. With Claude, you can enable features like chat, search, summarization, and more with just a few lines of code.

In this comprehensive guide, we will cover how to get started with the Claude API in Python, walk through code examples for common use cases, and explain best practices for production integration. By the end, you’ll have all the knowledge needed to start building AI-powered apps with Claude.

Overview of Claude API

Claude provides a REST API that allows sending text prompts and receiving AI-generated responses programmatically. Here are some key capabilities:

  • Chat – Have natural conversations with Claude to get helpful answers on a wide range of topics.
  • Search – Query Claude’s knowledge using search syntax to find highly relevant information.
  • Summarization – Provide long-form text and Claude will generate a concise summary capturing the main points.
  • Classification – Submit text and Claude will categorize it into pre-defined classes.
  • Semantic Search – Index documents and find the most relevant results for search queries.
  • Sentiment Analysis – Determine if input text expresses positive, negative, or neutral sentiment.
  • Translation – Translate text between English and 100+ languages.
  • QA – Ask Claude questions and receive accurate answers with relevant context.
  • Moderation – Check text or images for harmful content and get moderation predictions.

The API is exposed via HTTPS endpoints that accept and return JSON. There are also officially supported Python and JavaScript client libraries to make integration easier.

Now let’s look at how to call the API from Python specifically.

Getting Started with Claude Python

To start using Claude API in your Python application, you will need to:

  1. Sign up for a Claude API key
  2. Install the Claude Python package
  3. Import and initialize the Claude client

Let’s go through each of these steps:

1. Get a Claude API Key

First, you’ll need to get an API key which allows you to authenticate your requests to the Claude API. Here’s how to get your API key:

  1. Go to the Claude dashboard and click on “Get API Key”.
  2. Sign up for a free account if you don’t already have one.
  3. From the dashboard, create a new application to get your API key.
  4. Copy the API key to use in your Python code.
  5. You can find your API keys again later in your Anthropic account settings.

2. Install the Claude Python Package

Next, you’ll need to install the claude-python package to integrate Claude into your Python application.

You can install it from PyPI using pip:

This will install the latest version of the package.

3. Import and Initialize the Client

Now in your Python code, you can import and initialize the Claude client like this:

Replace YOUR_API_KEY with your actual API key.

The ClaudeClient will handle all requests to the API as well as data serialization.

And that’s it – you’re now ready to start using the Claude API!

Next let’s look at examples for accomplishing common tasks.

Core API Use Cases

The Claude API supports a wide range of capabilities through its Chat, Search, and Classify endpoints.

Here we’ll provide Python code snippets for some of the most popular use cases.


The /chat endpoint allows you to have a natural conversation with Claude about any topic:

The chat method accepts a list of messages with alternating user/assistant roles.

It returns the full conversation including Claude’s responses.

Some tips forChat:

  • Send multi-turn conversations by appending each message to the list.
  • Claude can chat casually, answer questions factually, and have nuanced discussions.
  • Use the stream=True parameter to get responses streamed in real-time.


To search Claude’s extensive knowledge base, use the /search endpoint:

The search syntax allows natural language queries as well as advanced operators.

Some examples:

  • first man on the moon – Fact lookup using keywords
  • explain quantum computing LI5 – Explain a topic simply
  • 3 blue oranges * (4 + 5) – Evaluate math expressions

Refer to the search guide for the full syntax.


To get a summarized version of a long text, use the /summary endpoint:

Claude will return a concise summary covering the key points in the original text.

You can customize the summary length and other parameters:

  • length – Number of sentences in the summary
  • max_input_length - Truncate input text to this limit before summarizing


For text classification tasks, use the /classify endpoint:

Some of the built-in classifiers:

  • sentiment – Positive/negative sentiment
  • toxicity – Toxic, severely toxic, obscene etc.
  • sexual – Explicit sexual content
  • violence – Violent content

You can also train custom classifiers through the dashboard.

Question Answering

To have Claude answer questions based on context, use the /qa endpoint:

Provide the context and question, and Claude will return the answer extracted from the context.


To translate text, use the /translate endpoint:

Claude supports translations between English and over 100 languages.

Specify the source_language and target_language using language codes like "en", "fr", "de" etc.

Production Best Practices

When moving your application to production with Claude, keep these best practices in mind:

Increase Timeout

The default API timeout i s 10 seconds. When making multiple requests in parallel or requesting long summaries/translations, increase the timeout parameter to allow more time:

Retry on Failure

Network requests can occasionally fail. Implement standard retry logic to call the API again if a request fails:

This will retry up to 3 times on request failures.

Cache Responses

For high-volume usage, cache Claude responses in a database or cache like Redis to avoid hitting API rate limits.

Queue Background Jobs

For long-running tasks like summarizing large texts, queue the job in the background rather than calling the API directly from the request path.

Monitor Costs

Keep an eye on your monthly API usage and costs from the Claude dashboard. Set up alerts if nearing your quota.

Upgrade for More Resources

Higher tiers offer higher rate limits and lower costs. Upgrade seamlessly as your app scales.


That wraps up this comprehensive guide on using Claude’s powerful AI through the Python API in your applications.

We covered:

  • Getting set up with an API key and the Python client
  • Code examples for Claude’s conversational, search, summarization and other capabilities
  • Best practices for taking your app into production

The Claude API enables you to quickly integrate state-of-the-art AI into any software application.

To learn more, refer to the full Claude API documentation, Python library docs, and Anthropic’s website.


How do I get an API key?

You can get a free Claude API key by signing up on the Anthropic website and creating an application. Your API keys are available in your account settings.

What Python version does the library require?

The claude-python library requires Python 3.6 or higher.

How do I pass API parameters?

Pass API parameters like model, length, etc as keyword arguments to the client methods like claude.classify(), claude.summary(), etc.

How do I upload documents for semantic search?

Use the claude.upload_document() method to upload documents for indexing. Then search against them with claude.semantic_search().

What is the rate limit?

The free tier has a limit of 50 requests per minute. Paid tiers have higher limits. Check the dashboard to monitor usage.

How do I batch multiple requests in one call?

Use the claude.batch() method which accepts a list of API requests and returns a combined response.

What is the maximum input size?

The maximum text size Claude can process is 10,000 tokens. Longer input will be truncated.

How do I customize Claude’s response voice/style?

Use parameters like voice and style to make Claude’s responses more professional, concise, specific domains, etc.

What languages does Claude support?

Claude supports English and 100+ languages through the translation API. The NLP models only support English currently.

How do I report issues with the API?

Report any bugs or issues on the Anthropic Community forums for support.