Discover how the QUIC protocol fundamentally solves years of internet performance and security challenges, bringing you the next-generation web experience.
The core of HTTP/3 is the QUIC (Quick UDP Internet Connections) protocol. It abandons traditional TCP in favor of UDP transport, implementing reliability, flow control, and congestion control at the application layer.
This shift enables faster connection establishment and integrates encryption directly into the protocol.
After the initial visit, QUIC allows clients to use cached security parameters to achieve 0-RTT (Zero Round-Trip Time) connection establishment in many scenarios.
This means you can send application data alongside the connection request, drastically reducing network latency. For returning users, loading is nearly instantaneous.
In TCP and HTTP/2, if a single packet is lost, all streams on the entire connection are paused waiting for retransmission. This is known as HoL Blocking.
QUIC uses independent Streams internally. Blockage in one stream doesn't affect others, achieving true parallel transmission and improving stability for complex sites.
QUIC connections do not rely on traditional IP address and port pairs. Instead, they use a Connection ID (CID) to identify the connection.
When a user switches from Wi-Fi to cellular data, changing their IP address, the QUIC connection remains active without needing to re-establish the session.
HTTP/2 uses HPACK. Since QUIC streams are independent, using HPACK directly could cause compression state confusion. Thus, HTTP/3 introduces QPACK.
QPACK is optimized for QUIC, allowing non-blocking transmission of header fields at the cost of a tiny bit of compression efficiency.