Is this free HTTP/2 checker really free to use?

Yes. You can run as many checks as you need without creating an account or paying any fees.

How to check if a website uses HTTP/2 on a mobile device?

The interface is fully responsive. Just open the page in your mobile browser, paste the URL, and tap the check button.

Why does the tool say HTTP/1.1 when my server config says HTTP/2?

Your configuration might not have reloaded properly, or an intermediate proxy like a firewall is stripping the ALPN extension. Check your server error logs and ensure TLS 1.2 or higher is enabled, since the newer protocol requires a modern TLS version.

Does this work for sites that only support plain HTTP?

Yes. If the site uses plain HTTP without TLS, the tool will report that it lacks support, since the protocol strictly requires an encrypted connection.

HTTP/2 Checker

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Use this free HTTP/2 checker to see if a domain supports the HTTP/2 protocol. Just paste a URL to check the connection without any signup required.

How the http2 checker verifies protocol support

You paste a URL. The tool opens a TCP connection to the target server and performs a TLS handshake. It inspects the Application-Layer Protocol Negotiation extension during this handshake. If the server advertises h2, the connection upgrades immediately. The tool then reports the exact negotiated protocol version back to you.

Because HTTP/2 multiplexes multiple requests over a single TCP connection, it drastically reduces latency compared to older standards that suffered from head-of-line blocking. You get header compression and server push capabilities when the protocol is active. Our free HTTP/2 checker simply confirms if this initial negotiation succeeds on the remote host.

When to test website for http2 support

Web performance audits require this exact data. You might be migrating a legacy application and need to verify your reverse proxy configuration. Checking the protocol ensures your Nginx or Apache settings actually took effect after a restart. It also helps when debugging slow page loads on modern browsers that expect multiplexed streams.

Sometimes a CDN sits in front of your origin server. The CDN might support the newer protocol while your origin only speaks version one. Running an online HTTP/2 checker against your public domain confirms the edge node handles the upgrade correctly. You avoid guessing if your caching layer is configured right.

Verifying reverse proxy configurations after a server migration.
Debugging slow page loads on modern browsers.
Confirming CDN edge nodes handle protocol upgrades correctly.

Limits of the http2 checker tool

This tool only checks the public-facing endpoint. It cannot inspect internal microservices or private subnets. If your load balancer terminates TLS and forwards plain text to the backend, the checker only sees the load balancer. You must test the backend directly if you need to verify internal protocol support.

Some servers negotiate the upgrade but fail to implement it correctly. The checker confirms the handshake succeeded. It does not run a full RFC compliance suite. You might see the protocol advertised while the server drops connections under heavy concurrent stream loads. Use dedicated load testing tools for that specific scenario.

How to use the http2 checker

Paste the target domain or full URL into the input field.
Click the check button to initiate the TLS handshake.
Wait for the tool to resolve the DNS and connect to the IP address.
Read the output to see if the server negotiated h2 or fell back to the older version.

HTTP/1.1 versus HTTP/2 feature comparison

This table highlights the core differences you see when a server successfully negotiates the newer protocol.

Feature	HTTP/1.1	HTTP/2
Connection handling	One request per connection	Multiplexed streams
Header format	Plain text	HPACK compressed
Server push	Not supported	Supported natively
Binary format	Textual	Binary framing

Frequently asked questions

Is this free HTTP/2 checker really free to use?: Yes. You can run as many checks as you need without creating an account or paying any fees.
How to check if a website uses HTTP/2 on a mobile device?: The interface is fully responsive. Just open the page in your mobile browser, paste the URL, and tap the check button.
Why does the tool say HTTP/1.1 when my server config says HTTP/2?: Your configuration might not have reloaded properly, or an intermediate proxy like a firewall is stripping the ALPN extension. Check your server error logs and ensure TLS 1.2 or higher is enabled, since the newer protocol requires a modern TLS version.
Does this work for sites that only support plain HTTP?: Yes. If the site uses plain HTTP without TLS, the tool will report that it lacks support, since the protocol strictly requires an encrypted connection.