Performance Tools

HTTP Version Checker

Detect which HTTP protocol version a website serves (HTTP/1.1, HTTP/2, or HTTP/3).

Enter a domain to detect which HTTP protocol version it serves.

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JustChecker tracks your website's performance signals continuously.

What Is the HTTP Version Checker?

It shows which HTTP protocol version the server used to answer our request - HTTP/1.1 or HTTP/2. Newer versions load pages faster by sending many files over one connection.

When to Use It

When checking whether your hosting or CDN supports HTTP/2.
As part of a page speed review.

How to Use It

Enter the domain.
Read the protocol version.

Understanding the Result

HTTP/2 is the modern baseline and requires HTTPS in browsers. If you see HTTP/1.1, enable HTTP/2 in your web server (for example http2 on the Nginx listen line) or use a CDN.

Limitations

HTTP/3 runs over a different transport (QUIC) and is announced with an Alt-Svc header; browsers switch to it on later requests, so a server may support HTTP/3 even when this check shows HTTP/2.

Frequently Asked Questions

HTTP/2 allows multiple requests to be multiplexed over a single connection (rather than opening many separate connections) and supports header compression, both meaningfully reducing page load latency, especially for pages with many resources.

Yes - HTTP/3 runs over QUIC (built on UDP rather than TCP), which eliminates a specific performance problem called head-of-line blocking and generally improves performance on unreliable or high-latency networks, like mobile connections.

It usually requires explicit server or CDN configuration to enable HTTP/2 or HTTP/3 - many older setups, or configurations that haven't been revisited recently, remain on HTTP/1.1 by default.

No - this is a transport-layer protocol change handled entirely at the server/CDN configuration level, completely transparent to your application code and content.

While the HTTP/2 specification technically permits plain http, in practice every major browser only implements HTTP/2 over an encrypted https connection - so enabling HTTP/2 effectively requires https already being in place.

Yes - servers negotiate the best protocol version each specific client supports, automatically falling back to HTTP/2 or HTTP/1.1 for clients that don't yet support HTTP/3, so no visitors are excluded.