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Time to first byte (TTFB) is a measurement used as an indication of the responsiveness of a webserver or other network resource.
TTFB measures the duration from the user or client making an HTTP request to the first byte of the page being received by the client's browser. This time is made up of the socket connection time, the time taken to send the HTTP request, and the time taken to get the first byte of the page.Although sometimes misunderstood as a post-DNS calculation, the original calculation of TTFB in networking always includes network latency in measuring the time it takes for a resource to begin loading. Often, a smaller (faster) TTFB size is seen as a benchmark of a well-configured server application. For example, a lower time to first byte could point to fewer dynamic calculations being performed by the webserver, although this is often due to caching at either the DNS, server, or application level. More commonly, a very low TTFB is observed with statically served web pages, while larger TTFB is often seen with larger, dynamic data requests being pulled from a database.
TTFB is often used by web search engines like Google and Yahoo to improve search rankings since a website will respond to the request faster and be usable before other websites would be able to.There are downsides to this metric since a web-server can send only the first part of the header before the content is even ready to send to reduce their TTFB. While this may seem deceptive it can be used to inform the user that the webserver is in fact active and will respond with content shortly. There are several reasons why this deception is useful, including that it causes a persistent connection to be created, which results in fewer retry attempts from a browser or user since it has already received a connection and is now preparing for the content download.
Load time is how long it takes for a webpage to be loaded and usable by a browser. Often in web page delivery a page is compressed in the Gzip format to make the size of the download smaller.This practice prevents the first byte from being sent until the compression is complete and increases the TTFB significantly. TTFB can go from 100–200 ms to 1000–20000 ms, but the page will load much faster and be ready for the user in a much smaller amount of time. Many websites see a common 5–10× increase in TTFB but a much faster browser response time garnering 20% load-time decrease.
In computing, Common Gateway Interface (CGI) is an interface specification that enables web servers to execute an external program to process HTTP/S user requests.
The Hypertext Transfer Protocol (HTTP) is an application layer protocol in the Internet protocol suite model for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web, where hypertext documents include hyperlinks to other resources that the user can easily access, for example by a mouse click or by tapping the screen in a web browser.
The World Wide Web (WWW), commonly known as the Web, is an information system that enables content sharing over the Internet through user-friendly ways meant to appeal to users beyond IT specialists and hobbyists. It allows documents and other web resources to be accessed over the Internet according to specific rules of the Hypertext Transfer Protocol (HTTP).
A web server is computer software and underlying hardware that accepts requests via HTTP or its secure variant HTTPS. A user agent, commonly a web browser or web crawler, initiates communication by making a request for a web page or other resource using HTTP, and the server responds with the content of that resource or an error message. A web server can also accept and store resources sent from the user agent if configured to do so.
In computing, load balancing is the process of distributing a set of tasks over a set of resources, with the aim of making their overall processing more efficient. Load balancing can optimize the response time and avoid unevenly overloading some compute nodes while other compute nodes are left idle.
In computer networking, a proxy server is a server application that acts as an intermediary between a client requesting a resource and the server providing that resource. It improves privacy, security, and performance in the process.
Squid is a caching and forwarding HTTP web proxy. It has a wide variety of uses, including speeding up a web server by caching repeated requests, caching World Wide Web (WWW), Domain Name System (DNS), and other computer network lookups for a group of people sharing network resources, and aiding security by filtering traffic. Although used for mainly HTTP and File Transfer Protocol (FTP), Squid includes limited support for several other protocols including Internet Gopher, Secure Sockets Layer (SSL), Transport Layer Security (TLS), and Hypertext Transfer Protocol Secure (HTTPS). Squid does not support the SOCKS protocol, unlike Privoxy, with which Squid can be used in order to provide SOCKS support.
Virtual hosting is a method for hosting multiple domain names on a single server. This allows one server to share its resources, such as memory and processor cycles, without requiring all services provided to use the same host name. The term virtual hosting is usually used in reference to web servers but the principles do carry over to other Internet services.
A content delivery network, or content distribution network (CDN), is a geographically distributed network of proxy servers and their data centers. The goal is to provide high availability and performance by distributing the service spatially relative to end users. CDNs came into existence in the late 1990s as a means for alleviating the performance bottlenecks of the Internet as the Internet was starting to become a mission-critical medium for people and enterprises. Since then, CDNs have grown to serve a large portion of the Internet content today, including web objects, downloadable objects, applications, live streaming media, on-demand streaming media, and social media sites.
Ajax is a set of web development techniques that uses various web technologies on the client-side to create asynchronous web applications. With Ajax, web applications can send and retrieve data from a server asynchronously without interfering with the display and behaviour of the existing page. By decoupling the data interchange layer from the presentation layer, Ajax allows web pages and, by extension, web applications, to change content dynamically without the need to reload the entire page. In practice, modern implementations commonly utilize JSON instead of XML.
In computing, the same-origin policy (SOP) is an important concept in the web application security model. Under the policy, a web browser permits scripts contained in a first web page to access data in a second web page, but only if both web pages have the same origin. An origin is defined as a combination of URI scheme, host name, and port number. This policy prevents a malicious script on one page from obtaining access to sensitive data on another web page through that page's Document Object Model (DOM).
Push technology or server push is a style of Internet-based communication where the request for a given transaction is initiated by the publisher or central server. It is contrasted with pull, or get, where the request for the transmission of information is initiated by the receiver or client.
The Simple Common Gateway Interface (SCGI) is a protocol for applications to interface with HTTP servers, as an alternative to the CGI protocol. It is similar to FastCGI but is designed to be easier to parse. Unlike CGI, it permits a long-running service process to continue serving requests, thus avoiding delays in responding to requests due to setup overhead.
Web analytics is the measurement, collection, analysis, and reporting of web data to understand and optimize web usage. Web analytics is not just a process for measuring web traffic but can be used as a tool for business and market research and assess and improve website effectiveness. Web analytics applications can also help companies measure the results of traditional print or broadcast advertising campaigns. It can be used to estimate how traffic to a website changes after launching a new advertising campaign. Web analytics provides information about the number of visitors to a website and the number of page views, or create user behavior profiles. It helps gauge traffic and popularity trends, which is useful for market research.
CGI:IRC is a CGI program written in Perl that allows access to IRC via a web browser. It is designed to be flexible and has many uses such as an IRC gateway for an IRC network, a chat-room for a website or to access IRC when stuck behind a restrictive firewall.
A single-page application (SPA) is a web application or website that interacts with the user by dynamically rewriting the current web page with new data from the web server, instead of the default method of a web browser loading entire new pages. The goal is faster transitions that make the website feel more like a native app.
WebSocket is a computer communications protocol, providing full-duplex communication channels over a single TCP connection. The WebSocket protocol was standardized by the IETF as RFC 6455 in 2011. The current API specification allowing web applications to use this protocol is known as WebSockets. It is a living standard maintained by the WHATWG and a successor to The WebSocket API from the W3C.
Web performance refers to the speed in which web pages are downloaded and displayed on the user's web browser. Web performance optimization (WPO), or website optimization is the field of knowledge about increasing web performance.