HTTP/3 Check | Test If HTTP/3 Is Enabled

Enter a URL above to check which HTTP protocol version it supports.

HTTP/3 HTTP/2 HTTP/1.1

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Free HTTP/3 Protocol Test

Check if any website supports HTTP/3, the latest HTTP protocol built on QUIC. HTTP/3 eliminates head-of-line blocking, reduces connection latency, and improves performance on unreliable networks.

Enter a URL to instantly verify HTTP/3 and QUIC support, view alt-svc headers, and check the full response. Essential for developers and site owners optimizing for modern web performance.

Frequently Asked Questions

What is HTTP/3?: HTTP/3 is the latest HTTP protocol that uses QUIC instead of TCP. It provides faster connections, better performance on mobile networks, and eliminates head-of-line blocking.
How does HTTP/3 differ from HTTP/2?: HTTP/3 uses QUIC (UDP-based) instead of TCP, enabling 0-RTT connections and independent stream handling. This means packet loss on one stream doesn't block others.
How do I enable HTTP/3?: Enable HTTP/3 through your CDN (Cloudflare, Fastly, AWS CloudFront) or configure your web server with QUIC support. The server advertises HTTP/3 via the alt-svc header.

Disclaimer

This website is developed by technical SEO consultant and ex-Google engineer Fili.

Bugs will happen and despite best efforts to maintain the code base and data quality, no guarantees can and/or will be given. Data may be incomplete, lost and/or errors may occur. This is a personal website and for-fun project. Use at your own risk.