What is HTTP/2? (original) (raw)

Last Updated : 23 Jul, 2025

HTTP/2 is the new version of HTTP, which transfers data over the Web. HTTP/2 is important for transmitting data from client to server over the web. Over time, various developments were made to enhance web protocols' efficiency, performance, and safety. HTTP/2 provides various features to transmit data over the internet or web. In this article, we were going to discuss HTTP/2.

What is HTTP?

HTTP stands for Hypertext Transfer Protocol, it is a protocol through which hypertext is transferred over the web. Hypertext Transfer Protocol was invented by Tim Berner in 1989. The World Wide Web allows people to share data like text, photos, and multimedia files. When a user opens their web browser, they indirectly use HTTP.

Problems in HTTP

HTTP suffers from a Head of Line Blocking issue.
HTTP demands high processing power to establish communication and data transfer.
HTTP is less secure.
HTTP is only utilized to establish point-to-point connections.
HTTP is not suitable for mobile devices.
HTTP does not provide reliable communication.

What is HTTP/2?

HTTP/2 was developed in 2015 as a new version of HTTP. HTTP/2 addresses various issues of HTTP and Head of Line Blocking issues. HTTP/2 is faster and more efficient than HTTP. One of the ways HTTP/2 improves performance is by prioritizing data throughout the loading process. HTTP/2 decreases performance limitations while maintaining compatibility with existing applications. HTTP/2 improves network resources and reduces latency by reducing header fields.

History of HTTP/2

HTTP/2 is the most recent HTTP protocol, introduced in May 2015. It is supported by many browsers like Chrome, Internet Explorer 11, Safari, and Firefox. Note that HTTP/2 is not known as HTTP/2.0 since the IETF (Internet Engineering Task Force) considers HTTPP/2 to be an advanced protocol that does not require future sub-versions. If major changes are required in the future, they will be published using HTTP/3. HTTP/2 not only improves performance, but it is also compatible with the HTTP/1.1 structure, which has similar features to the SPDY protocol.

Features of HTTP/2

**Multiplexing: Multiplexing allows several requests and responses to be sent over a single connection, which improves performance by reducing connection overhead and improving network resource utilization.
**Binary Protocol: Unlike HTTP which is a text-based protocol, HTTP/2 uses a binary protocol, which reduces data size and improves efficiency.
**Server Push: HTTP/2 allows servers to "push" responses into client caches rather than waiting for a new request for every resource.
**Backward Compatibility: HTTP/2 is backward compatible with HTTP.
**Decreasing Round Trip Time: HTTP/2 decreases extra Round Trip Time(RTT), allowing your website to load faster without any optimization.
**Increase Throughput: HTTP/2 reduced network latency and increased throughput.
**Provide Security: HTTP/2 supports response prioritization, flow control, and good handling of Transport Layer Security(TLS).

HTTP/2

Advantages of HTTP/2

HTTP/2 is the binary protocol rather than the textual protocol.
HTTP/2 reduces overhead by using header compression HPACK.
HTTP/2 provides stream prioritization which ensures that the critical resources are delivered first.
HTTP/2 enables servers to "push" responses proactively into client caches rather than waiting for a new request for each resource.
HTTP/2 employs the new ALPN extension, which enables quicker encrypted connections.
HTTP/2 reduces extra round trip times (RTT), which allows your website to load faster.

Disadvantages of HTTP/2

Implementation of HTTP/2 is more complex due to the additional new features like multiplexing, header compression, and stream prioritization.
Additional latency is introduced due to TLS.
HTTP/2 suffers from the Head of Line Blocking problem at the transport layer.
There are some interoperability issues in HTTP/2.
There is some complementation and bugs issues in HTTP/2.

Differences Between HTTP/2 and HTTP

HTTP/2	HTTP
HTTP/2 works on Binary Protocol.	HTTP works on Textual Protocol.
HTTP/2 headers are compressed which leads to low Overheating.	HTTP leads to high Overheading because headers are sent as plain text.
HTTP/2 supports Multiplexing.	HTTP does not support Multiplexing.
HTTP/2 uses ALPN extension which allows faster encrypted connection.	HTTP allows slower encrypted connections.
HTTP/2 support Servers Push.	HTTP does not support Server Push.
HTTP/2 provides stream prioritization which ensures that the critical resources are delivered first.	There is no built-in support for stream prioritization.
HTTP/2 performance is better than HTTP.	The performance of HTTP is low as compared to HTTP/2

Conclusion

HTTP/2 includes several essential optimizations over the previous HTTP protocol. These advantages have prompted many businesses to adopt the HTTP/2 protocol. HTTP/2 features help to reduce latency, make reloading of webpages faster, and more efficient use of network resources, and hence improve the overall performance and user experience of web applications and services.