What is HTTP/2?

What problems does HTTP/2 solve and its advantages, HTTP/3 vs HTTP/2

HTTP/2 (originally named HTTP 2.0) is the second version of the Hypertext Transfer Protocol, used for the World Wide Web. It is primarily based on the SPDY protocol, implementing measures such as data compression of HTTP header fields, multiplexing of data transmission, and server push to reduce network latency and enhance client page load speed. HTTP/2 does not change the application semantics of HTTP, still utilizing HTTP request methods, status codes, and header fields. It primarily modifies the message transmission format of HTTP, enhancing performance through the introduction of binary framing.

What problems does HTTP/2 solve?

HTTP is the most widely used internet application protocol. The early versions of the HTTP protocol were simple: HTTP/0.9 started the World Wide Web with only one line of protocol; HTTP/1.0 was an official specification that extended the popular HTTP/0.9; it wasn't until HTTP/1.1 that the IETF published the first official standard. In the early stages, simplicity came at the cost of application performance: HTTP/1.1 required clients to use multiple connections to achieve concurrency and reduce latency; HTTP/1.1 did not compress request and response header fields, leading to unnecessary network traffic; HTTP/1.1 did not support effective resource prioritization, resulting in low utilization of underlying TCP connections, and so on.

As network applications have become integral to people's daily lives, their scope, complexity, and importance have continued to expand. To address issues with the HTTP protocol, HTTP/2 was introduced. HTTP/2 did not change the application semantics of HTTP, continuing to use HTTP's request methods, status codes, and header fields. It primarily modified the message transmission format of HTTP, reducing network latency and improving client page load speeds through measures such as introducing server push.

HTTP/2 vs HTTP/1.1

HTTP/2 and HTTP/1.1 are two different versions of HTTP (Hypertext Transfer Protocol) used for transmitting web pages and other resources over the network. There are several key differences between them:

  1. Binary protocol: HTTP/2 uses a binary protocol, while HTTP/1.1 uses a text-based protocol. Binary protocols are easier to parse, more efficient, and less error-prone.
  2. Multiplexing: HTTP/2 supports multiplexing, which means that multiple requests and responses can be sent and received simultaneously over a single TCP connection. This reduces latency and improves resource utilization. In contrast, HTTP/1.1 uses multiple TCP connections to achieve similar functionality, but with less efficiency.
  3. Header compression: HTTP/2 employs the HPACK compression algorithm to compress HTTP header information, reducing the size of transmitted data. This helps improve performance, especially in low-bandwidth environments. HTTP/1.1 does not support header compression.
  4. Server push: HTTP/2 supports server push, allowing the server to proactively send resources before the client requests them. This helps reduce round-trip times and improve performance. HTTP/1.1 does not support this feature.
  5. Stream prioritization: HTTP/2 allows for the prioritization of different requests so that more important resources can be transmitted faster. HTTP/1.1 does not have this capability.

HTTP/2 offers significant improvements in performance, efficiency, and functionality compared to HTTP/1.1, making it a better choice for modern web applications. However, some older clients and servers may still only support HTTP/1.1. In practice, it's best to ensure that your server supports both protocols for forward compatibility and maximum performance benefits.

HTTP/2 vs HTTP/3

HTTP/3, also referred to as QUIC (Quick UDP Internet Connections), represents the most recent version of HTTP and offers numerous benefits compared to HTTP/2:

  1. Reduced latency: HTTP/3 uses QUIC, which operates over UDP instead of TCP, reducing connection establishment times and overall latency.
  2. Improved congestion control: QUIC includes improved congestion control mechanisms, which can lead to better performance, especially in situations with packet loss or high latency.
  3. Multiplexing: HTTP/3 allows for more efficient multiplexing, enabling multiple streams to be sent over a single connection without head-of-line blocking issues.
  4. Security: QUIC includes built-in encryption, providing security at the transport layer, which is an improvement over the optional use of TLS with HTTP/2.
  5. Better error correction: QUIC includes improved error correction mechanisms, which can help mitigate the impact of packet loss and retransmissions.

These advantages make HTTP/3 a compelling option for improving web performance and security over its predecessor, HTTP/2.

curl HTTP/2

you can use the curl command to make HTTP/2 requests. To do this, you need to ensure that your version of curl supports HTTP/2. You can check this by running:

curl --version

and looking for HTTP2 in the features list. If your version supports HTTP/2, you can use the 


 flag to enable HTTP/2, like this:

curl -v --http2 https://example.com


Tencent Cloud's EdgeOne Service provides extensive support for modern protocols like HTTP/2, HTTP/3. Here is a breakdown of how each is supported:

  1. EdgeOne supports the HTTP/2 protocol, which brings a significant performance boost compared to the previous HTTP/1.x protocols. As mentioned earlier, this includes benefits from binary framing, multiplexing, server push, header compression, and stream prioritization. The end result is improved site speed and reliability, especially for complex, resource-intensive websites.
  2. EdgeOne supports HTTP/3 (QUIC) requests which are used to further accelerate site requests and improve data transfer efficiency and security. HTTP/3 uses QUIC instead of TCP as a transport protocol, which helps reduce round-trip time and speed up the delivery of the web content.