HTTP3 Status API: Check if HTTP 3.0 Protocol is Enabled

A JSON API to check if a specific URL supports HTTP/3.0 by analyzing response headers and connection-level protocol negotiation. Use this API to quickly check whether a URL supports the modern HTTP/3.0 protocol and the available Alt-Svc (Alternative Services) protocols and ports.

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Consumes 1 credit per API call

# Example Curl request from the command line:
                          
curl -X POST "https://api.apivoid.com/v2/http3-status" \
     -H "Content-Type: application/json" \
     -H "X-API-Key: YOUR_API_KEY_HERE" \
     -d '{"url": "https://www.google.com/"}'

# Example JSON output for a 200 HTTP status code:

{
    "url": "https://www.google.com/",
    "status_code": 200,
    "http3_supported": true,
    "protocol": "HTTP/3.0",
    "response_headers": {
        "accept-ch": [
            "Sec-CH-Prefers-Color-Scheme"
        ],
        "alt-svc": [
            "h3=\":443\"; ma=2592000,h3-29=\":443\"; ma=2592000"
        ],
        "cache-control": [
            "private, max-age=0"
        ],
        "content-security-policy-report-only": [
            "object-src 'none';base-uri 'self';script-src 'nonce-Nz8mAqnUcP9DMyCbaZACLw' 'strict-dynamic' 'report-sample' 'unsafe-eval' 'unsafe-inline' https: http:;report-uri https://csp.withgoogle.com/csp/gws/other-hp"
        ],
        "content-type": [
            "text/html; charset=UTF-8"
        ],
        "cross-origin-opener-policy": [
            "same-origin-allow-popups; report-to=\"gws\""
        ],
        "date": [
            "Sat, 28 Jun 2025 17:55:35 GMT"
        ],
        "expires": [
            "-1"
        ],
        "p3p": [
            "CP=\"This is not a P3P policy! See g.co/p3phelp for more info.\""
        ],
        "report-to": [
            "{\"group\":\"gws\",\"max_age\":2592000,\"endpoints\":[{\"url\":\"https://csp.withgoogle.com/csp/report-to/gws/other\"}]}"
        ],
        "server": [
            "gws"
        ],
        "set-cookie": [
            "AEC=AVh_V2g4JwBRVJn7WAfWfVudgZMgly5haB1MAR-BKzHH1UnQvoCDDleChw; expires=Thu, 25-Dec-2025 17:55:35 GMT; path=/; domain=.google.com; Secure; HttpOnly; SameSite=lax",
            "NID=525=isACz11NxPsswU2YOPlbZrH-LP60h2pmGnhvILMuWapj-YIKD8PuAifKjEZhYEoll5VGoGyDh9vBIP-A2rZokyr5fGNF65OrlUKyc6GESio6OsT31D6Ad3AP3dVixrVqAA9ENlsc5S6Uzeg7lbe4EFjoJvLcfmw7xFcckzBrlyJnBbaTfbX9SZeErYWYhuJq8qN9Yoe5TsxZnJEonST2a0s; expires=Sun, 28-Dec-2025 17:55:35 GMT; path=/; domain=.google.com; Secure; HttpOnly; SameSite=none"
        ],
        "x-frame-options": [
            "SAMEORIGIN"
        ],
        "x-xss-protection": [
            "0"
        ]
    },
    "alpn_identifiers": [
        "h3",
        "h3-29"
    ],
    "elapsed_ms": 77
}

Test HTTP/3.0 protocol to improve security and ensure compliance

Businesses and startups use this HTTP3 Test API to instantly detect whether the new HTTP/3.0 protocol is enabled on a URL, along with retrieving HTTP response headers and Alt-Svc.

HTTP/3.0 Status

A simple and fast API to identify if HTTP/3.0 is properly enabled and supported on a URL.

Security Compliance

Modern websites should adopt HTTP/3.0 to deliver faster performance and stronger security.

Extract Alt-Svc Entries

The API returns also the HTTP response headers and all Alternative Services parsed into an array.

Fast Response

The submitted URL is analyzed in real-time and the response is returned in 1-3 seconds on average.

Take a look at some real-world use cases of this API service

Our API can be used in many ways, from cybersecurity tasks to research-specific tasks. Here we showcase the most popular use cases according to our customers usage:

Track HTTP/3.0 Usage

Scan a list of popular URLs to find out which ones have enabled the new HTTP/3.0 protocol.

A Tool for Your Users

Empower your users with a tool to instantly check if any URL is using HTTP/3.0 for faster performance.

Enrich URL Information

Using a SIEM or CRM platform? Add context to URL-related data, show if the URL supports HTTP/3.0.

Check Your Customers

Use this API to monitor and verify whether your customers' websites are using the HTTP/3.0 protocol.

$url = 'https://www.google.com/'; $apiUrl = 'https://api.apivoid.com/v2/http3-status'; $apiKey = 'your_api_key_here'; $ch = curl_init($apiUrl); curl_setopt($ch, CURLOPT_RETURNTRANSFER, true); curl_setopt($ch, CURLOPT_HTTPHEADER, ['Content-Type: application/json', 'X-API-Key: ' . $apiKey]); curl_setopt($ch, CURLOPT_POST, true); curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode(['url' => $url])); $response = curl_exec($ch); $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE); curl_close($ch); if ($httpCode === 200) { $responseData = json_decode($response, true); print_r($responseData); }