Get started with Claude

Prerequisites

An Anthropic Console account
An API key

Call the API

Set your API key

Get your API key from the Anthropic Console and set it as an environment variable:

export ANTHROPIC_API_KEY='your-api-key-here'

Make your first API call

Run this command to create a simple web search assistant:

curl https://api.anthropic.com/v1/messages \
  -H "Content-Type: application/json" \
  -H "x-api-key: $ANTHROPIC_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -d '{
    "model": "claude-sonnet-4-20250514",
    "max_tokens": 1000,
    "messages": [
      {
        "role": "user", 
        "content": "What should I search for to find the latest developments in renewable energy?"
      }
    ]
  }'

Example output:

{
  "id": "msg_01HCDu5LRGeP2o7s2xGmxyx8",
  "type": "message", 
  "role": "assistant",
  "content": [
    {
      "type": "text",
      "text": "Here are some effective search strategies to find the latest renewable energy developments:\n\n## Search Terms to Use:\n- \"renewable energy news 2024\"\n- \"clean energy breakthrough\"\n- \"solar/wind/battery technology advances\"\n- \"green energy innovations\"\n- \"climate tech developments\"\n- \"energy storage solutions\"\n\n## Best Sources to Check:\n\n**News & Industry Sites:**\n- Renewable Energy World\n- GreenTech Media (now Wood Mackenzie)\n- Energy Storage News\n- CleanTechnica\n- PV Magazine (for solar)\n- WindPower Engineering & Development..."
    }
  ],
  "model": "claude-sonnet-4-20250514",
  "stop_reason": "end_turn",
  "usage": {
    "input_tokens": 21,
    "output_tokens": 305
  }
}

Set your API key

Get your API key from the Anthropic Console and set it as an environment variable:

export ANTHROPIC_API_KEY='your-api-key-here'

Make your first API call

Run this command to create a simple web search assistant:

curl https://api.anthropic.com/v1/messages \
  -H "Content-Type: application/json" \
  -H "x-api-key: $ANTHROPIC_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -d '{
    "model": "claude-sonnet-4-20250514",
    "max_tokens": 1000,
    "messages": [
      {
        "role": "user", 
        "content": "What should I search for to find the latest developments in renewable energy?"
      }
    ]
  }'

Example output:

{
  "id": "msg_01HCDu5LRGeP2o7s2xGmxyx8",
  "type": "message", 
  "role": "assistant",
  "content": [
    {
      "type": "text",
      "text": "Here are some effective search strategies to find the latest renewable energy developments:\n\n## Search Terms to Use:\n- \"renewable energy news 2024\"\n- \"clean energy breakthrough\"\n- \"solar/wind/battery technology advances\"\n- \"green energy innovations\"\n- \"climate tech developments\"\n- \"energy storage solutions\"\n\n## Best Sources to Check:\n\n**News & Industry Sites:**\n- Renewable Energy World\n- GreenTech Media (now Wood Mackenzie)\n- Energy Storage News\n- CleanTechnica\n- PV Magazine (for solar)\n- WindPower Engineering & Development..."
    }
  ],
  "model": "claude-sonnet-4-20250514",
  "stop_reason": "end_turn",
  "usage": {
    "input_tokens": 21,
    "output_tokens": 305
  }
}

Set your API key

Get your API key from the Anthropic Console and set it as an environment variable:

export ANTHROPIC_API_KEY='your-api-key-here'

Install the SDK

Install the Anthropic Python SDK:

pip install anthropic

Create your code

Save this as quickstart.py:

import anthropic

client = anthropic.Anthropic()

message = client.messages.create(
    model="claude-sonnet-4-20250514",
    max_tokens=1000,
    messages=[
        {
            "role": "user",
            "content": "What should I search for to find the latest developments in renewable energy?"
        }
    ]
)
print(message.content)

Run your code

python quickstart.py

Example output:

[TextBlock(text='Here are some effective search strategies for finding the latest renewable energy developments:\n\n**Search Terms to Use:**\n- "renewable energy news 2024"\n- "clean energy breakthroughs"\n- "solar/wind/battery technology advances"\n- "energy storage innovations"\n- "green hydrogen developments"\n- "renewable energy policy updates"\n\n**Reliable Sources to Check:**\n- **News & Analysis:** Reuters Energy, Bloomberg New Energy Finance, Greentech Media, Energy Storage News\n- **Industry Publications:** Renewable Energy World, PV Magazine, Wind Power Engineering\n- **Research Organizations:** International Energy Agency (IEA), National Renewable Energy Laboratory (NREL)\n- **Government Sources:** Department of Energy websites, EPA clean energy updates\n\n**Specific Topics to Explore:**\n- Perovskite and next-gen solar cells\n- Offshore wind expansion\n- Grid-scale battery storage\n- Green hydrogen production\n- Carbon capture technologies\n- Smart grid innovations\n- Energy policy changes and incentives...', type='text')]

Set your API key

Get your API key from the Anthropic Console and set it as an environment variable:

export ANTHROPIC_API_KEY='your-api-key-here'

Install the SDK

Install the Anthropic TypeScript SDK:

npm install @anthropic-ai/sdk

Create your code

Save this as quickstart.ts:

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

async function main() {
  const anthropic = new Anthropic();

  const msg = await anthropic.messages.create({
    model: "claude-sonnet-4-20250514",
    max_tokens: 1000,
    messages: [
      {
        role: "user",
        content: "What should I search for to find the latest developments in renewable energy?"
      }
    ]
  });
  console.log(msg);
}

main().catch(console.error);

Run your code

npx tsx quickstart.ts

Example output:

{
  id: 'msg_01ThFHzad6Bh4TpQ6cHux9t8',
  type: 'message',
  role: 'assistant',
  model: 'claude-sonnet-4-20250514',
  content: [
    {
      type: 'text',
      text: 'Here are some effective search strategies to find the latest renewable energy developments:\n\n' +
        '## Search Terms to Use:\n' +
        '- "renewable energy news 2024"\n' +
        '- "clean energy breakthroughs"\n' +
        '- "solar wind technology advances"\n' +
        '- "energy storage innovations"\n' +
        '- "green hydrogen developments"\n' +
        '- "offshore wind projects"\n' +
        '- "battery technology renewable"\n\n' +
        '## Best Sources to Check:\n\n' +
        '**News & Industry Sites:**\n' +
        '- Renewable Energy World\n' +
        '- CleanTechnica\n' +
        '- GreenTech Media (now Wood Mackenzie)\n' +
        '- Energy Storage News\n' +
        '- PV Magazine (for solar)...'
    }
  ],
  stop_reason: 'end_turn',
  usage: {
    input_tokens: 21,
    output_tokens: 302
  }
}

Set your API key

Get your API key from the Anthropic Console and set it as an environment variable:

export ANTHROPIC_API_KEY='your-api-key-here'

Install the SDK

Add the Anthropic Java SDK to your project. First find the current version on Maven Central.

Gradle:

implementation("com.anthropic:anthropic-java:1.0.0")

Maven:

<dependency>
  <groupId>com.anthropic</groupId>
  <artifactId>anthropic-java</artifactId>
  <version>1.0.0</version>
</dependency>

Create your code

Save this as QuickStart.java:

import com.anthropic.client.AnthropicClient;
import com.anthropic.client.okhttp.AnthropicOkHttpClient;
import com.anthropic.models.messages.Message;
import com.anthropic.models.messages.MessageCreateParams;

public class QuickStart {
    public static void main(String[] args) {
        AnthropicClient client = AnthropicOkHttpClient.fromEnv();

        MessageCreateParams params = MessageCreateParams.builder()
                .model("claude-sonnet-4-20250514")
                .maxTokens(1000)
                .addUserMessage("What should I search for to find the latest developments in renewable energy?")
                .build();

        Message message = client.messages().create(params);
        System.out.println(message.content());
    }
}

Run your code

javac QuickStart.java
java QuickStart

Example output:

[ContentBlock{text=TextBlock{text=Here are some effective search strategies to find the latest renewable energy developments:

## Search Terms to Use:
- "renewable energy news 2024"
- "clean energy breakthroughs"  
- "solar/wind/battery technology advances"
- "energy storage innovations"
- "green hydrogen developments"
- "renewable energy policy updates"

## Best Sources to Check:
- **News & Analysis:** Reuters Energy, Bloomberg New Energy Finance, Greentech Media
- **Industry Publications:** Renewable Energy World, PV Magazine, Wind Power Engineering
- **Research Organizations:** International Energy Agency (IEA), National Renewable Energy Laboratory (NREL)
- **Government Sources:** Department of Energy websites, EPA clean energy updates

## Specific Topics to Explore:
- Perovskite and next-gen solar cells
- Offshore wind expansion
- Grid-scale battery storage
- Green hydrogen production..., type=text}}]

Next steps

Now that you have made your first Anthropic API request, it’s time to explore what else is possible:

Features Overview

Explore Claude’s advanced features and capabilities.

Client SDKs

Discover Anthropic client libraries.

Anthropic Cookbook

Learn with interactive Jupyter notebooks.

First steps

Models & pricing

Learn about Claude

Capabilities

Tools

Model Context Protocol (MCP)

Use cases

Prompt engineering

Test & evaluate

Strengthen guardrails

Legal center

Get started with Claude

Prerequisites

Call the API

Next steps

Features Overview

Client SDKs

Anthropic Cookbook

First steps

Models & pricing

Learn about Claude

Capabilities

Tools

Model Context Protocol (MCP)

Use cases

Prompt engineering

Test & evaluate

Strengthen guardrails

Legal center

​Prerequisites

​Call the API

​Next steps

Features Overview

Client SDKs

Anthropic Cookbook

Prerequisites

Call the API

Next steps