3 Best Ways to Access Claude 3.7 Sonnet API for Free in 2025

Claude 3.7 Sonnet has emerged as one of the most powerful AI models on the market, with exceptional reasoning, coding, and problem-solving capabilities. However, Anthropic recently placed this advanced model behind a paywall, making direct API access require a paid subscription. The good news? There are still legitimate ways to access Claude 3.7 Sonnet API for free.

In this comprehensive guide, we’ll explore three proven methods to access Claude 3.7 Sonnet without paying, plus reveal an exclusive discounted option that gives you the best value for professional use.

Is Claude 3.7 Sonnet Still Available for Free?

Many users have reported that after a single prompt with Claude 3.7 Sonnet, they received a notification requiring an upgrade to a paid Pro plan to continue using it. This follows the same pattern seen with Claude 3.5 Sonnet, which was temporarily restricted before becoming available again.

While direct access through Claude.ai now requires a subscription, the three methods outlined below provide legitimate free alternatives to continue leveraging this powerful AI model without payment.

Method 1: Free Claude 3.7 API Access Through Puter.js

Puter.js offers perhaps the most straightforward way to access Claude 3.7 Sonnet API without any keys or usage restrictions. This client-side solution operates on a “User Pays” model, eliminating the need for developers to handle API key management or server-side infrastructure.

How to Use Puter.js for Free Claude 3.7 API Access:

1. Include the Puter.js Script: Add the script tag to your HTML file:

   <script src="https://js.puter.com/v2/"></script>

2. Make API Calls: Use the puter.ai.chat() function to generate text:

   puter.ai.chat("Your prompt here", {model: 'claude-3-7-sonnet'})
       .then(response => {
           console.log(response.message.content[0].text);
       });

3. Stream Responses (Optional): For longer outputs, use streaming:

   const response = await puter.ai.chat(
       "Your prompt here", 
       {model: 'claude-3-7-sonnet', stream: true}
   );
   
   for await (const part of response) {
       console.log(part?.text);
   }

Puter.js provides unlimited access without API keys and works directly in the browser, making it ideal for web applications and testing.

Method 2: Accessing Claude 3.7 API Through Cursor

Cursor, an AI-powered code editor, offers another excellent way to leverage Claude 3.7 Sonnet’s capabilities at no cost. The platform has integrated Claude 3.7 Sonnet directly into its core functionality, providing free access to all users regardless of subscription status.

Steps to Access Claude 3.7 Through Cursor:

1. Download and Install Cursor: Visit the official Cursor website and download the version for your operating system.
2. Launch and Configure: Open Cursor and navigate to Settings.
3. Select Claude 3.7 Sonnet: In the AI model settings, choose Claude 3.7 Sonnet from the available options.

Cursor is particularly valuable for developers who want to leverage Claude’s advanced coding capabilities for free. The integration is seamless and provides the full power of Claude 3.7 Sonnet for coding tasks.

Method 3: Free Claude 3.7 API Access with Trae

Trae, a relatively new AI-powered code editor from ByteDance, offers perhaps the most generous free access to Claude 3.7 Sonnet among all options. Unlike some alternatives that have usage limits or trial periods, Trae provides unlimited free access to Claude 3.7 Sonnet for all users.

How to Use Claude 3.7 with Trae:

1. Download and Install Trae: Visit Trae’s official website and download the appropriate version.
2. Launch the Application: After installation, open Trae on your system.
3. Select Claude 3.7 Sonnet: Navigate to the AI model settings and choose Claude 3.7 Sonnet.

Trae’s unlimited free access to Claude 3.7 Sonnet makes it an exceptional choice for developers who need ongoing access to this powerful model without subscription costs.

Bonus: Get Discounted Claude 3.7 API Access via laozhang.ai

While the above methods provide free access with certain limitations, professional developers and businesses might need direct API access with greater reliability and control. For these users, laozhang.ai offers a compelling alternative.

laozhang.ai provides Claude 3.7 Sonnet API access at up to 50% discount compared to direct pricing, making it the most cost-effective option for professional usage. Their service offers:

• Simple API integration with standard OpenAI-compatible endpoints
• Pay-as-you-go pricing with no minimum commitments
• Access to 500+ global AI models beyond just Claude
• Free credits upon registration

Example API Call with laozhang.ai:

curl https://api.laozhang.ai/v1/chat/completions \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $API_KEY" \
  -d '{
    "model": "claude-3-7-sonnet",
    "stream": false,
    "messages": [
      {"role": "system", "content": "You are a helpful assistant."},
      {"role": "user", "content": "Hello!"} 
    ]
  }'

For developers seeking the best balance of cost and reliability, register with laozhang.ai to receive free credits and access to their discounted API services.

Comparing Free Claude 3.7 API Access Methods

Conclusion: Best Free Claude 3.7 API Options in 2025

While Claude 3.7 Sonnet is now behind a paywall for direct access, you have multiple legitimate options to continue using it for free:

• Puter.js – Ideal for web developers needing client-side AI integration
• Cursor – Perfect for programmers and developers focusing on code
• Trae – Great for those needing unlimited access for development
• laozhang.ai – Best value for professional use with discounted API access

By leveraging these methods, you can continue to harness the power of Claude 3.7 Sonnet without paying full price – or in many cases, without paying at all. For professional needs requiring direct API access, laozhang.ai’s discounted service provides the most cost-effective solution.

Have questions about implementing any of these methods? Feel free to contact me for assistance.