This quickstart uses X-Unsafe-API-Key which is not safe for production.See the nextjs-ts example for a more robust example.
TL;DR
1
Steal this code
Save the following code locally as
index.html.2
Open in browser
Open
index.html in your browser.3
Add API key
Add your Ultravox API key.
4
Start call
Click the button.
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Ultravox Web Quickstart</title>
<script src="https://cdn.tailwindcss.com"></script>
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.4.0/css/all.min.css">
</head>
<body class="bg-gray-100 min-h-screen py-8">
<div class="max-w-4xl mx-auto px-4">
<div class="bg-white rounded-lg shadow-lg p-6">
<!-- WARNING: DO NOT USE IN PRODUCTION -->
<div class="bg-yellow-50 border-l-4 border-yellow-400 p-4 mb-6">
<div class="flex">
<div class="flex-shrink-0 fas fa-exclamation-triangle text-yellow-400"></div>
<div class="ml-3">
<h3 class="text-sm text-yellow-800">DEVELOPMENT ONLY - DO NOT USE IN PRODUCTION</h3>
<p class="mt-1 text-sm text-yellow-700">This interface exposes API keys in client-side code and uses unsafe headers to bypass CORS.</p>
<p class="mt-1 text-sm text-yellow-700">For a robust example, see the <a href="https://github.com/fixie-ai/ultravox-examples/tree/main/web/nextjs-ts">nextjs-ts</a> example.</p>
</div>
</div>
</div>
<form class="space-y-6">
<div class="bg-gray-50 rounded-lg p-4">
<h3 class="text-sm text-gray-900 mb-2">Call Status</h3>
<div id="callStatus" class="text-sm text-gray-600">Ready</div>
</div>
<div>
<label for="apiKey" class="block text-sm text-gray-700 mb-2">Ultravox API Key:</label>
<input type="password" id="apiKey"
class="w-full px-3 py-2 border border-gray-300 rounded-md shadow-sm focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-blue-500"
placeholder="Enter your Ultravox API key">
<p class="mt-1 text-sm text-gray-500">Your API key will be used to create the call. Keep this secure!</p>
</div>
<div>
<label for="systemPrompt" class="block text-sm text-gray-700 mb-2">System Prompt:</label>
<textarea id="systemPrompt" rows="3"
class="w-full px-3 py-2 border border-gray-300 rounded-md shadow-sm focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-blue-500"
placeholder="Enter system prompt for the AI assistant">You are a helpful assistant.</textarea>
<p class="mt-1 text-sm text-gray-500">This prompt will define how the AI assistant behaves during the call.</p>
</div>
<div class="flex space-x-3">
<button type="button" id="startCall"
class="inline-flex items-center px-4 py-2 border border-transparent text-sm rounded-md shadow-sm text-white bg-green-600 hover:bg-green-700 focus:outline-none focus:ring-2 focus:ring-offset-2 focus:ring-green-500 transition-colors">
Start Call
</button>
<button type="button" id="endCall"
class="inline-flex items-center px-4 py-2 border border-transparent text-sm rounded-md shadow-sm text-white bg-red-600 hover:bg-red-700 focus:outline-none focus:ring-2 focus:ring-offset-2 focus:ring-red-500 transition-colors">
End Call
</button>
</div>
</form>
</div>
</div>
<script type="module">
import { UltravoxSession } from 'https://esm.sh/ultravox-client@0.3.6';
let uvSession = new UltravoxSession();
function appendUpdate(target, message) {
const updateTarget = document.getElementById(target);
if(target === 'callTranscript') {
let transcriptText = '';
message.map((transcript, index) => (
transcriptText += '<div class="p-2 bg-gray-50 rounded border-l-4 border-blue-400"><span class="font-semibold text-gray-800">' + transcript.speaker + ':</span> <span class="text-gray-700">' + transcript.text + '</span></div>'
));
updateTarget.innerHTML = transcriptText;
updateTarget.scrollTop = updateTarget.scrollHeight;
} else {
updateTarget.innerHTML = message;
}
}
// ⚠️ WARNING: DO NOT USE IN PRODUCTION! ⚠️
// This function makes API calls directly from the client with API keys exposed
// API keys should never be handled in client-side code in production
// In production, API calls should be made from a secure server
// Here we are using unsafe API endpoint to bypass CORS - this is a security risk
async function createCall(apiKey, systemPrompt) {
try {
appendUpdate('callStatus', '<span class="text-blue-600">Creating call...</span>');
const payload = {
temperature: 0.3,
systemPrompt: systemPrompt
};
console.log('Creating call with payload:', payload);
// ⚠️ WARNING: X-Unsafe-API-Key header is used to bypass CORS ⚠️
// This is NOT secure and should NEVER be used in production
const response = await fetch('https://api.ultravox.ai/api/calls', {
method: 'POST',
headers: {
'Content-Type': 'application/json',
'X-Unsafe-API-Key': apiKey // ⚠️ UNSAFE - DO NOT USE IN PROD ⚠️
},
body: JSON.stringify(payload)
});
if (!response.ok) {
throw new Error(`HTTP error! status: ${response.status}`);
}
const callData = await response.json();
console.log('Call created successfully:', callData);
return callData.joinUrl;
} catch (error) {
console.error('Error creating call:', error);
appendUpdate('callStatus', `<span class="text-red-600">Error creating call: ${error.message}</span>`);
throw error;
}
}
// Start Call button click event handler
document.getElementById('startCall').onclick = async function() {
const apiKey = document.getElementById('apiKey').value;
const systemPrompt = document.getElementById('systemPrompt').value || 'You are a helpful assistant.';
if (!apiKey) {
appendUpdate('callStatus', '<span class="text-red-600">Please enter your Ultravox API key</span>');
return;
}
try {
const joinUrl = await createCall(apiKey, systemPrompt);
if (!joinUrl) {
appendUpdate('callStatus', '<span class="text-red-600">Failed to get join URL from API</span>');
return;
}
appendUpdate('callStatus', '<span class="text-blue-600">Joining call...</span>');
uvSession.addEventListener('status', (event) => {
let statusClass = 'text-blue-600';
if (uvSession.status === 'connected') statusClass = 'text-green-600';
if (uvSession.status === 'disconnected') statusClass = 'text-gray-600';
appendUpdate('callStatus', `<span class="${statusClass}">Session status: ${uvSession.status}</span>`);
});
uvSession.joinCall(joinUrl);
} catch (error) {
appendUpdate('callStatus', `<span class="text-red-600">Failed to start call: ${error.message}</span>`);
}
};
// End Call button click event handler
document.getElementById('endCall').onclick = async function() {
appendUpdate('callStatus', '<span class="text-yellow-600">Ending call...</span>');
uvSession.leaveCall();
};
</script>
</body>
</html>
Next Steps
- Check out the nextjs-ts example for a more complete, production ready web app.