How to check if my browser supports HTTP/3?

Use our free HTTP/3 browser check tool to test if your browser supports HTTP/3 and QUIC protocols. Simply visit our site and run the test. Modern browsers like Chrome, Firefox, and Edge support HTTP/3 and QUIC protocols.

A QUIC test verifies if a server or browser supports the QUIC protocol, which powers HTTP/3 connections. Our QUIC test tool checks protocol support, connection performance, and QUIC handshake capabilities.

How do I test HTTP3 online?

To test HTTP3 online, simply enter your domain name in our HTTP/3 check tool above. Our tool will verify if your website supports HTTP/3 and QUIC protocols and provide detailed connection metrics.

HTTP/3 Check - QUIC Browser Test

Test your website and browser for HTTP/3 and QUIC protocol support online - Free browser check tool

example.com

check_circle QUIC is supported

check_circle HTTP/3 is supported

HTTP/3 Check established a QUIC connection for all attempts made with the given endpoint. The server is using HTTP/3. See the metrics below for more information.

0-RTT

Zero Round Trip Time Resumption (0-RTT)

The QUIC handshake for this connection was completed without any additional round-trips.

SUCCESS

QUIC Versions

These are the QUIC versions supported by this QUIC endpoint.

AGREED SUPPORTED

Connection ID	Packet RX	Handshake Done
5ababd60...	5.46	5.37

HTTP/3 Server Information

HTTP Version: HTTP/3

Server: cloudflare

Status Code: 200

Response Time: 51.25 ms

Response Headers

Header	Value
date	Fri, 09 Oct 2026 04:40:17 GMT
content-type	text/html; charset=utf-8
priority	u=3,i=?0
server	cloudflare
last-modified	Sun, 04 Oct 2026 20:44:03 GMT
cf-cache-status	HIT
allow	GET, HEAD
accept-ranges	bytes
age	1688
cf-ray	a47ab4d5da5462da-HAM
alt-svc	h3=":443"; ma=86400
server-timing	cfExtPri

HTTP/3 Statistics

Zero Round Trip Time Resumption (0-RTT)

The QUIC handshake for this connection was completed without any additional round-trips.

SUCCESS

QUIC Versions

These are the QUIC versions supported by this QUIC endpoint.

AGREED SUPPORTED

Connection ID

This unique identifier for a QUIC connection is used to ensure that changes to an endpoint's lower network layer address (UDP/IP) does not affect the delivery of the QUIC connection's packets.

This tool attempts two connections to test the server's 0-RTT capabilities. During the first connection, the client receives important handshake material from the server. With 0-RTT, the client can start to send data immediately if it uses this handshake material when it creates the second connection.

Packet RX

This value represents the time between the first packet sent and the first packet received (measured in milliseconds).

Handshake Done

This value represents the time between when the first packet is sent and when the handshake is completed (measured in milliseconds).

Take notice of the difference in this metric between the first connection and the second connection. Using 0-RTT, future connections (i.e. the second connection) can complete the handshake much faster than the original connection.