Skip to main content
wp-config.org

Website and domain checks

HTTP/2 support test

Check whether the final public HTTPS address really negotiates HTTP/2 when this site connects to it.

  • Real negotiation
  • Redirects followed
  • HTTPS only

Free, no sign-up. Lookups and results are not saved by this site.

This tool needs JavaScript. Turn JavaScript on and reload the page.

HTTP/2 test

HTTP/2 lets a browser load many files over one connection. This test asks for HTTP/2 over a secure connection and reads the protocol the connection actually used, rather than guessing from a header.

Technical references: curl HTTP version options (opens in a new tab) and HTTP/2 specification (RFC 9113) (opens in a new tab).

What you can do

  • The real HTTP/2 negotiation result

  • HTTP/1 fallback reported, never a false pass

  • The public redirect chain

  • HTTPS certificate checks

  • Clear notes on what the test cannot see

How to use it

  1. Enter the address

    Enter a public HTTPS address without a username, password or other private details.

  2. Run the test

    Start the test. A quick Cloudflare security check runs first, then this site checks the address and its redirects before connecting.

  3. Read the result

    Read the result, the evidence and the limits. If you change a server or CDN setting, run the test again.

How the HTTP/2 test works

HTTP/2 lets many requests share one connection. This test asks for HTTP/2 over TLS and reads the protocol the connection really chose, rather than guessing from a response header.

Know the limits

It tests HTTP/2 over HTTPS, not cleartext h2c. A connection can use HTTP/2 and still return an error page, and that still shows support. One request that does not use HTTP/2 does not prove the server never supports it, and a CDN can answer before your server does.

Frequently asked questions

How is HTTP/2 support verified?

The test asks for HTTP/2 over a secure connection and reads the protocol the connection actually used from curl. Only a real HTTP/2 connection is reported as negotiated.

What if HTTP/1 is returned?

The result says the connection fell back to HTTP/1 and that HTTP/2 was not negotiated on that request. It does not claim the website can never use HTTP/2.

Does this test HTTP/2 without HTTPS?

No. It tests HTTP/2 over HTTPS only. It does not try cleartext HTTP/2 (h2c) or nonstandard ports.

Does a 403 or 404 mean HTTP/2 is not supported?

No. A server can negotiate HTTP/2 and then return an error page. The protocol and the response status are reported separately.

Are these results for my origin server or my CDN?

The checker connects to the public URL. A CDN, reverse proxy or load balancer may answer instead, so the result does not show how your origin server itself is set up.

What is sent when I run a test?

Your URL and a fresh Cloudflare Turnstile response are sent to this site. After the security check, our server makes a few limited public requests. Page contents and cookies are not returned or saved.

Related tools

  • HTTP headers

    Inspect HTTP response headers and redirects.

  • Nginx

    Prepare routing, HTTPS and cache configuration.

  • DNS lookup

    Review DNS records and email policies.