SDKs

Learn how to use Retell’s Node.js and Python SDKs

While you can use our REST API for most operations, we recommend using our SDKs to speed up development and reduce code complexity. Our SDKs provide typed methods and a more structured approach to integrating with Retell.

​Available SDKs & Requirements

• Node.js TypeScript SDK

  • NPM Package

  • Requires Node.js version 18.10.0 or higher

• Python SDK

  • PyPI Package

  • Requires Python 3.x

1

Get Your API Key

Navigate to the “API Keys” tab in your dashboard to obtain your API key.

2

Install the SDK

Choose your preferred language and install the SDK:

Node ClientPython Client

npm i retell-sdk

3

Initialize the Client

Create a new client instance using your API key:

Node ClientPython Client

import Retell from 'retell-sdk';

const retellClient = new Retell({
  apiKey: "YOUR_API_KEY",
});

4

Make API Calls

Here’s an example of making a phone call using the SDK:

Node ClientPython Client

try {
  const response = await retellClient.call.createPhoneCall({
    from_number: '[phone]',
    to_number: '[phone]',
  });
  console.log('Call initiated:', response);
} catch (error) {
  console.error('Error making call:', error);
}

​SDK vs REST API Example

To illustrate the benefits of using our SDK, here’s a comparison of creating an agent using both methods:

​Using REST API (More Verbose)

const options = {
  method: 'POST',
  headers: {
    Authorization: '<authorization>',
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    response_engine: {
      type: 'retell-llm',
      llm_id: 'llm_234sdertfsdsfsdf'
    },
    agent_name: 'Jarvis',
    voice_id: '11labs-Adrian',
    // ... many more configuration options
  })
};

fetch('https://api.retellai.com/create-agent', options)
  .then(response => response.json())
  .then(response => console.log(response))
  .catch(err => console.error(err));

​Using SDK (More Concise)

import Retell from 'retell-sdk';

const client = new Retell({
  apiKey: 'YOUR_RETELL_API_KEY',
});

async function main() {
  const params: Retell.AgentCreateParams = {
    response_engine: { 
      llm_id: 'llm_234sdertfsdsfsdf',
      type: 'retell-llm'
    },
    voice_id: '11labs-Adrian',
  };
  const agentResponse = await client.agent.create(params);
}

​Best Practices

1. Error Handling: Always wrap SDK calls in try-catch blocks

2. Type Safety: Take advantage of TypeScript types in the Node.js SDK

3. API Reference: Refer to our API documentation for all available parameters

​Additional Resources

Find more SDK examples in our test suites to learn more about how to use the SDK:

• Node.js SDK Examples

• Python SDK Examples