Integrating Claude API for Smart Applications

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🚀 Technical Briefing: This tutorial is part of our deep-dive series on Agentic Workflows at Gate of AI. For the full technical breakdown, interactive code sandbox, and the native Arabic translation, visit the original article here.

<span>Tutorial</span>
<span>Intermediate</span>
<span>⏱ 45 min read</span>
<span>© Gate of AI 2026-06-21</span>

Learn how to integrate Claude and ChatGPT APIs into a smart application using modern SDKs for enhanced AI functionalities. Note: OpenAI's access to Claude API has been revoked.

Prerequisites

Node.js version 18.0 or later
Access to Anthropic API key
Intermediate JavaScript and React knowledge

What We're Building

In this tutorial, we will build a smart application that leverages the capabilities of both Claude and ChatGPT APIs. However, due to recent changes, OpenAI's access to Claude API has been revoked. We will focus on integrating Claude API for tasks such as language translation, sentiment analysis, and providing conversational responses.

By the end of this tutorial, you will have a working application that can switch between different AI models based on user input, demonstrating the power and flexibility of integrating multiple AI services.

Setup and Installation

First, we need to set up our development environment and install necessary packages. We'll be using Next.js for our application framework, which is built on top of React and provides server-side rendering out of the box.

npx create-next-app@latest my-smart-app --ts

cd my-smart-app

npm install anthropic

npm install dotenv

Next, configure your environment variables to secure your API keys. This is crucial for keeping sensitive information out of your source code.

// .env.local

ANTHROPIC_API_KEY=your-anthropic-api-key

Step 1: Setting Up API Clients

In this step, we'll set up clients to interact with the Anthropic API. This involves creating instances of the SDKs that will allow us to make requests to the APIs.

import { Anthropic } from 'anthropic';

const anthropicClient = new Anthropic(process.env.ANTHROPIC_API_KEY);

// Use this client to make API requests in your application

Here, we import the required library and instantiate the client using the API key from our environment variables. This setup allows us to access various functionalities provided by the API.

Step 2: Building the User Interface

Now we'll create a simple user interface using React components. This interface will allow users to input text and select which AI model they want to use for processing.

import { useState } from 'react';

function App() {

  const [inputText, setInputText] = useState('');

  const [model, setModel] = useState('claude');

  const [response, setResponse] = useState('');

const handleInputChange = (e) => setInputText(e.target.value);

  const handleModelChange = (e) => setModel(e.target.value);

return (

  <h1>Smart AI Application</h1>
        &lt;select value={model} onChange={handleModelChange}&gt;
    &lt;option value="claude"&gt;Claude&lt;/option&gt;
  &lt;/select&gt;
  &lt;button&gt;Submit&lt;/button&gt;
  &lt;p&gt;Response: {response}&lt;/p&gt;
&lt;/div&gt;



    

    




);

}

export default App;

</code></pre>

  <p>This code sets up a basic interface with a textarea for input, a dropdown to select the AI model, and a section to display the response. We'll connect this interface to our API client in the next steps.</p>

</section>

<section class="gai-section" id="gai-step3">

  <h2>Step 3: Connecting to the API</h2>

  <p>In this step, we will implement the logic to send the user's input to the selected AI model and display the response. We'll use asynchronous functions to handle API calls.</p>

  <pre class="gai-code-block"><code>const handleSubmit = async () => {

  let apiResponse;

apiResponse = await anthropicClient.messages.create({

    model: 'claude-3-5-sonnet-20241022',

    prompt: inputText

  });

setResponse(apiResponse.choices[0].message.content);

};

// Add this inside your App component

<button onClick={handleSubmit}>Submit</button>

</code></pre>

  <p>Here, we define an asynchronous function <code>handleSubmit</code> that sends the input to the Claude API. The response is then set to the state, which updates the UI to display it.</p>

</section>

<div class="gai-expert-tip">

  <strong>⚠️ Common Mistake:</strong> Ensure your API keys are correctly set in the environment variables. Incorrect keys will lead to authentication errors with the APIs.</div>

<section class="gai-section" id="gai-testing">

  <h2>Testing Your Implementation</h2>

  <p>To verify that our application works as expected, enter some text and select a model. Upon submission, you should see a response from the AI model.</p>

  <pre class="gai-code-block"><code>// Run your Next.js application

npm run dev

// Access the application via http://localhost:3000

</code></pre>

  <p>Check the console for any errors and ensure that the responses make sense based on the input and selected model.</p>

</section>

<section class="gai-section" id="gai-next">

  <h2>What to Build Next</h2>

  <ul>

    <li>Integrate additional AI models for more functionalities.</li>

    <li>Add user authentication to save and retrieve user settings.</li>

    <li>Implement a history feature to track past interactions.</li>

  </ul>

</section>

</article>

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