Verify¶

Validate configuration before starting httpd:

/path/to/httpd/bin/httpd -t
/path/to/httpd/bin/httpd -M | grep http3
ss -ulnp | grep 4433

The module list should show http3_module (shared), and the socket inspection should show a UDP listener on the selected port.

Test HTTP/3¶

Use a curl build with HTTP/3 support:

curl -V
curl --http3-only -k -sI https://localhost:4433/

curl -V must list HTTP3. --http3-only prevents fallback to HTTP/2 or HTTP/1.1, so a successful response proves a QUIC connection was used.

For trusted local testing, prefer --cacert /path/to/server.crt over -k.

See HTTP/3 testing with curl for GET, POST, PUT, concurrent stream, and failure-diagnosis commands.