HTTP/2 or current version
curl -sS -o /dev/null \
-w '%{http_code} %{http_version}\n' \
https://example.com/The command deliberately omits -L: a 3xx response means this URL redirects.
Methodology: This check follows wSEO methodology 1.1. How the assessment works
Independent protocol check
Test the exact canonical HTTPS address without following redirects
The primary hostname is already known from earlier checks. That exact address should respond directly; otherwise the test may measure another page or even another website.
Browser check
- Open the exact canonical HTTPS address in Chrome.
- Open More tools → Developer Tools.
- Select Network and reload the page.
- Enable the Protocol column from the table-heading context menu.
- Inspect the main HTML document rather than an advert or unrelated asset.
Reading the result
| Value | Meaning | Assessment |
|---|---|---|
h3 | HTTP/3 over QUIC | Excellent |
h2 | HTTP/2 | Expected |
http/1.1 | Older protocol | Repair |
| Redirect | The URL is not the final canonical response | Investigate |
Separate HTTP/3 test
curl --http3 -sS -o /dev/null \
-w '%{http_code} %{http_version}\n' \
https://example.com/If the local curl does not support --http3, use the browser; that is a local-tool limitation.
When HTTPS is unavailable
Do not test HTTP/2 or HTTP/3 separately. Configure the certificate and HTTPS first, then return to the protocol check.
When HTTP/3 works, still confirm that HTTP/2 remains available for clients and networks without QUIC. Save the Network screenshot and exact URL as evidence.
