HTTP/3 Checker

Check if a server supports HTTP/3 (QUIC) protocol

About HTTP/3

HTTP/3 is the latest version of the HTTP protocol, built on top of QUIC (Quick UDP Internet Connections) instead of TCP. QUIC provides faster connection establishment, improved multiplexing without head-of-line blocking, and better performance on unreliable networks. Our HTTP/3 Checker tests whether a server supports HTTP/3 by analyzing the Alt-Svc response header and QUIC protocol negotiation.

How to Use

Enter the domain name of the website you want to test for HTTP/3 support.
Click Check HTTP/3 to test the server's protocol capabilities.
Review the result to see if HTTP/3 is supported and examine the Alt-Svc header.
Use the information to plan HTTP/3 deployment or verify existing support.

Use Cases

Performance Optimization: Verify HTTP/3 deployment for faster page loads and reduced latency.
CDN Verification: Confirm that your CDN provider is delivering content via HTTP/3 as advertised.
Competitive Analysis: Check if competitor websites have adopted HTTP/3 for performance benchmarking.
Migration Planning: Assess HTTP/3 readiness before enabling QUIC on your own infrastructure.

Frequently Asked Questions

HTTP/3 uses QUIC over UDP instead of TCP, eliminating head-of-line blocking at the transport layer. QUIC also combines TLS 1.3 into its handshake, reducing connection setup from two round trips (TCP + TLS) to just one, significantly improving latency on slow connections.

Enabling HTTP/3 depends on your server software. Nginx supports it via the quiche or boringssl fork, Apache via mod_http3, and cloud services like Cloudflare and Fastly enable it automatically. Most major CDNs and hosting platforms now support HTTP/3 out of the box.

All major browsers including Chrome, Firefox, Edge, and Safari support HTTP/3. Safari has supported it since iOS 14 and macOS Big Sur. Browser support is now widespread, making HTTP/3 deployment practical for general web use.

Tips & Best Practices

•Enable HTTP/3 for improved performance on supported clients
•Verify HTTP/3 QUIC connection security and encryption
•Test HTTP/3 connectivity from different networks and clients
•Monitor HTTP/3 adoption and usage metrics

Technical Details

Protocol: HTTP/3 over QUIC support detection
Transport: QUIC transport protocol analysis
Security: QUIC encryption and security features
Output: HTTP/3 support status with performance analysis