Following an 18-year pause between the introduction of HTTP/1.1 in 1997 and HTTP/2 in 2015, development has accelerated, with the draft proposal for HTTP/3 published only three years later.

What Exactly Is HTTP/3?

HTTP/3 is essentially a redesign of the underlying transport layer often used to manage file transfers.

It represents a shift from TCP (Transmission Control Protocol) to UDP (User Datagram Protocol), solving various TCP shortcomings while boosting user performance and security.

HTTP/3 is already utilized by 25% of the top ten million websites, including Google and Facebook. In fact, if you’re using Google Analytics, Tag Manager, or Fonts, you’re already leveraging the protocol to some extent.

What Are the Primary Advantages of HTTP/3 Over HTTP/2 and HTTP/1?

It’s important taking a step back to understand how HTTP/1.1 works and the issues that HTTP/2 was supposed to address. HTTP/1.1 was intended to provide each file with its own connection. As websites grew more sophisticated, more files were required to load each page. Browsers restrict the number of parallel connections allowed, resulting in a bottleneck and poor loading times. This necessitated many performance-enhancing solutions, such as domain sharding and picture sprites.

HTTP/2 addresses the problem created by connection restrictions by introducing multiplexing, which enabled the transport of several files over a single connection. Another significant enhancement was the addition of greater header compression, as well as a few other elements that have proven less successful in reality.

However, the TCP problem was not resolved. TCP transports packets in chronological order, which means that if a packet is lost, the entire connection is suspended until the packet is securely received. Some of the advantages of multiplexing are negated by this issue, known as the head of line blocking. Another issue with TCP is that it is completely independent of the TLS protocol.

How Does HTTP/3 Address These Issues?

Individual Byte Streams
By offering distinct byte streams for each file, HTTP/3 eliminates head-of-line blocking. The data for a single stream is blocked while the lost packet is reissued, rather than the whole connection.

Integration of TLS
Instead of having two different protocols working independently, adding TLS 1.3 into HTTP/3 requires only a single handshake, decreasing the number of roundtrips from two (or three if using TLS 1.2) to one. Users will benefit from faster – and more secure connections with this improvement.

Connection Transfer
HTTP/3 routes packets using connection IDs rather than IP addresses. This allows it to manage network changes without having to re-establish a connection. This is extremely useful in a mobile-first environment, as users frequently switch between wifi and cellular networks for speed and connection reliability.

Conclusion
HTTP/3 is a big step forward for the web, providing a much-needed speed increase to enable its ongoing evolution. As SEO and digital marketing experts, we should be aware of the protocol’s benefits ahead of its upcoming release so that we may begin encouraging its use and allow our users to reap the benefits for years to come.