Major revision of the HTTP network protocol used by the World Wide Web.

- HTTP/2

46 related topics



Obsolete open-specification communication protocol developed for transporting web content.

A BBC Domesday Project machine with its modified LaserDisc reader. Published in 1986, the BBC Domesday Project became the subject of intense preservation efforts beginning in 2002.

SPDY became the basis for HTTP/2 specification.

List of HTTP header fields

HTTP header fields are a list of strings sent and received by both the client program and server on every HTTP request and response.

Strings are often made up of characters. They are useful for storing human-readable data, like sentences, or lists of alphabetical data, like the nucleic acid sequences of DNA.

HTTP/2 and HTTP/3 instead use a binary protocol, where headers are encoded in a single and zero or more frames using HPACK (HTTP/2) or QPACK (HTTP/3), which both provide efficient header compression.

Internet Information Services

Extensible web server software created by Microsoft for use with the Windows NT family.

Screenshot of IIS Manager console of Internet Information Services 8.5


Hypertext Transfer Protocol

Application layer protocol in the Internet protocol suite model for distributed, collaborative, hypermedia information systems.

URL beginning with the HTTP scheme and the WWW domain name label
Tim Berners-Lee
An HTTP/1.1 request made using telnet. The request message, response header section, and response body are highlighted.

HTTP/2 is a more efficient expression of HTTP's semantics "on the wire", and was published in 2015; used by more than 46% of websites, now supported by almost all web browsers (96% of users) and major web servers over Transport Layer Security (TLS) using an Application-Layer Protocol Negotiation (ALPN) extension where TLS 1.2 or newer is required.

Web server

Computer software and underlying hardware that accepts requests via HTTP or its secure variant HTTPS.

PC clients communicating via network with a web server serving static content only.
The inside and front of a Dell PowerEdge server, a computer designed to be mounted in a rack mount environment. It is often used as a web server.
Multiple web servers may be used for a high traffic website.
Web server farm with thousands of web servers used for super-high traffic websites.
ADSL modem running an embedded web server serving dynamic web pages used for modem configuration.
First web proposal (1989) evaluated as "vague but exciting..."
The world's first web server, a NeXT Computer workstation with Ethernet, 1990. The case label reads: "This machine is a server. DO NOT POWER IT DOWN!!"
Sun's Cobalt Qube 3 – a computer server appliance (2002, discontinued)
PC clients connected to a web server via Internet
PC clients communicating via network with a web server serving static and dynamic content.
Directory listing dynamically generated by a web server.
Market share of all sites for most popular web servers 2005–2021
Market share of all sites for most popular web servers 1995–2005

implementing HTTP/2 was considered a task of overwhelming complexity that could open the door to a whole new class of bugs that till 2015 did not exist and so it would have required notable investments in developing and testing the implementation of the new protocol;

Communication protocol

System of rules that allows two or more entities of a communications system to transmit information via any kind of variation of a physical quantity.

Figure 2. The TCP/IP model or Internet layering scheme and its relation to some common protocols.
Figure 3. Message flows using a protocol suite. Black loops show the actual messaging loops, red loops are the effective communication between layers enabled by the lower layers.
Figure 5: Protocol and software layering. The software modules implementing the protocols are represented by cubes. The information flow between the modules is represented by arrows. The (top two horizontal) red arrows are virtual. The blue lines mark the layer boundaries.

Binary have been used in the normative documents describing modern standards like EbXML, HTTP/2, HTTP/3 and EDOC.

Apache HTTP Server

Free and open-source cross-platform web server software, released under the terms of Apache License 2.0.

HTTP/2 support

Google Chrome

Cross-platform web browser developed by Google.

Google Chrome running on Windows 11
Google Chrome running on Windows 11
An early version of Chromium for Linux, explaining the difference between Chrome and Chromium
The results of the Acid3 test on Google Chrome 4.0
Google Chrome Incognito mode message
Screenshot of a Chrome browser crash
Google Chrome Canary application icon
Google Chrome running on an Android phone
Usage share of web browsers according to StatCounter

This was due to SPDY being replaced by HTTP/2, a standard that was based upon it.


Protocol Stack of HTTP/3 compared to HTTP/1.1 and HTTP/2

HTTP/3 is the third major version of the Hypertext Transfer Protocol used to exchange information on the World Wide Web, alongside HTTP/1.1 and HTTP/2.


Web server that can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache.

HTTP/1.1 Upgrade (101 Switching Protocols), HTTP/2 protocol support