index.html

<html>
    <head><title>Service account example</title></head>
    <body>
        <ul>
            <li><a href="app-secret">Client authentication with client secret</a><br /><br /></li>
            <li><a href="app-jwt">Client authentication with JWT signed by client private key</a></li>
        </ul>
    </body>
</html>