HTTP/2 vs HTTP/3 Check
Check whether your connection is using HTTP/3.
Where this comes from
When your browser loaded this page it negotiated an HTTP version with our edge. The tool reports which one, along with the TLS version.
What the results mean
- HTTP/3
- The newest version, running over QUIC. Faster to establish and more resilient on lossy connections. Normal on modern browsers and networks.
- HTTP/1.1
- The oldest still common. Seeing it on a modern browser often means a proxy or security appliance is terminating the connection.
Common problems and fixes
- HTTP/3 is not being used on a modern browser
- Something in the path does not carry QUIC. Corporate networks and some home routers block UDP on port 443, which is what QUIC runs over, so the browser falls back to HTTP/2 over TCP. A security appliance terminating TLS produces the same result, since the connection you negotiate is with the appliance.
- It reports HTTP/3 on one network and HTTP/2 on another
- That is the expected shape of the answer, because the version is negotiated per connection and depends entirely on the path. Mobile networks, café Wi-Fi and office networks routinely differ. The version reported here describes this connection now, not a capability of your browser.
- A proxy is showing up that I did not configure
- On a managed device this is normal and deliberate — corporate TLS inspection terminates your connection, examines it and opens a new one, which is why the version and TLS details describe the appliance rather than the origin. On a personal machine it is worth investigating, since the same shape describes an interception you did not ask for.
Frequently asked questions
Why is my connection using HTTP/1.1?
On a modern browser and network you would expect HTTP/2 or HTTP/3. HTTP/1.1 usually means something is intercepting the connection — a corporate proxy, a security appliance, or occasionally an older network device.
Is HTTP/3 noticeably faster?
On a good connection, barely — you will not perceive the difference. It matters on lossy or high-latency links, where QUIC's independent streams mean one lost packet does not stall everything behind it, and its faster handshake saves a round trip on connection setup. Mobile networks are where it earns its keep.
Should I be worried about HTTP/1.1?
Not for correctness — everything works. It is worth investigating as a signal, because on a current browser and network you would expect HTTP/2 at least, and HTTP/1.1 usually means something is sitting in the middle of your connection. On a corporate network that is likely to be a sanctioned proxy; elsewhere it deserves a look.
Put this on your own site
Free to embed, no attribution required beyond the source link the frame carries itself. It runs entirely in your visitor's browser, sets no cookies and loads no third-party script.
<iframe src="https://runthetests.com/embed/http3-test/" width="100%" height="560" style="border:1px solid #e5e5e5;border-radius:8px" title="HTTP/2 vs HTTP/3 Check" loading="lazy"></iframe>
Preview it at https://runthetests.com/embed/http3-test/. Embedded pages are marked noindex, so yours stays the canonical copy — not this one.