HTTP + TLS
HTTP/2, HTTP/3, TLS 1.0 to 1.3 support and Alt-Svc.
Protocols supported by amscomputer.com
HTTP/2
Supported
HTTP/3
Not advertised
TLS versions
TLS 1.0
no
TLS 1.1
no
TLS 1.2
OK
TLS 1.3
OK
Modern best practice: HTTP/2 + TLS 1.2 minimum, ideally TLS 1.3 and HTTP/3.
About HTTP + TLS
This tool checks two things at once: which HTTP protocol versions the server speaks and which TLS versions it accepts. It opens a real HTTP/2 connection to test for HTTP/2 support and reads the Alt-Svc response header to see if HTTP/3 over QUIC is advertised. For TLS, it attempts a handshake with each version from TLS 1.0 through TLS 1.3, reporting which the server accepts and which it rejects.
When to use it
Use this when comparing hosting providers to see if their default stack supports modern protocols. Run it on your own sites to confirm HTTP/2 is enabled, since HTTP/1.1 is significantly slower for resource-heavy pages. Check TLS versions before a compliance audit, since PCI-DSS and many other frameworks require TLS 1.2 minimum with TLS 1.0 and 1.1 disabled.
How to read the results
Modern best practice is HTTP/2 supported, HTTP/3 advertised, TLS 1.2 and 1.3 accepted, TLS 1.0 and 1.1 rejected. If TLS 1.0 still works, your server is accepting weak crypto and should be reconfigured. HTTP/3 requires both server support and UDP port 443 to be unblocked by intermediate networks. The Alt-Svc header is the standard way servers tell clients HTTP/3 is available.
Frequently asked questions
Why is HTTP/2 better than HTTP/1.1? ▾
HTTP/2 multiplexes many requests over a single TCP connection, eliminating head-of-line blocking on the application layer. It also adds header compression. Real-world page loads with many small assets can be 30 to 50 percent faster on HTTP/2.
How is HTTP/3 different from HTTP/2? ▾
HTTP/3 runs over QUIC, a UDP-based transport. It eliminates TCP head-of-line blocking and survives client network changes (moving between WiFi and mobile) without re-establishing the connection. Loading is faster on lossy networks like mobile.
Should I disable TLS 1.0 and 1.1? ▾
Yes for almost every modern site. Browsers stopped supporting them in 2020. Keeping them on adds attack surface without serving real users. Cloud load balancers and most hosting panels let you disable them in one setting.
Why does Alt-Svc show HTTP/3 but my browser does not use it? ▾
Browsers cache HTTP/3 availability and only switch over after the first cached visit. Try reloading once or twice. Also confirm UDP port 443 is not blocked by your network, since corporate firewalls and some ISPs block UDP/443.