HTTP/2 & HTTP/3 Check

Test whether your server supports modern HTTP protocols, TLS 1.3, Brotli compression, and other performance features that speed up page delivery.

HTTP/2 & HTTP/3TLS 1.3Brotli~5 seconds
This tool analyzes the single URL you enter, not your entire website.
Analyzing... Testing protocol support and server configuration

What We Check

Protocol support, encryption, and performance features for modern web delivery.

HTTP/2 Support

Server supports HTTP/2 protocol

HTTP/3 Support

Server supports HTTP/3 (QUIC) protocol

Alt-Svc Header

Alt-Svc header advertises HTTP/3 support

TLS 1.3

TLS 1.3 is negotiated for connections

HSTS Header

Strict-Transport-Security header is present

Compression

Response compression is enabled (Gzip or Brotli)

Brotli Encoding

Brotli compression is supported

Keep-Alive

Persistent connections (Keep-Alive) enabled

TTFB

Time to First Byte is within acceptable range

Preload Hints

Preload hints found for critical resources

Frequently Asked Questions

Common questions about this tool.

What is the difference between HTTP/2 and HTTP/3?
HTTP/2 runs over TCP and introduces multiplexing, header compression, and server push. HTTP/3 replaces TCP with QUIC (based on UDP), eliminating head-of-line blocking and reducing connection setup time. HTTP/3 is especially beneficial on mobile networks and high-latency connections.
Does HTTP/2 require HTTPS?
Technically, the HTTP/2 specification allows unencrypted connections (h2c), but all major browsers only support HTTP/2 over TLS (h2). In practice, you need a valid SSL/TLS certificate to use HTTP/2. This also means your site benefits from both improved performance and encryption.
How does Brotli compare to Gzip?
Brotli typically achieves 15-20% smaller file sizes than Gzip at comparable compression levels, especially for HTML, CSS, and JavaScript. It uses a pre-defined dictionary of common web content patterns. All modern browsers support Brotli over HTTPS, and most CDNs and web servers can serve it alongside Gzip as a fallback.

Test Your Server Protocols

Find out if your server is using the latest HTTP protocols and encryption standards for maximum performance.

Start Audit
Speed TestSecurity CheckCarbon FootprintImage Optimizer