HTTP status message definitions

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The ability to request a resource via a unique URL. Once a client is authenticated, the state of the client should not affect access to an addressable resource.


URL aliasing. Providing alternate URLs for a resource that redirects to the canonical URL for that resource.


Application programming interface. A set of pre-determined functions that are exposed by an application or service for use by third-party developers. Web services will usually expose a documented API to detail how developers should interface with the service.



Software used for viewing web content. See also user agent.



Queensland Government Consistent User Experience Standard and template.

Canonical URL

The one authoritatively correct URL for a resource. When a resource can be accessed via multiple URLs, a canonical URL should be chosen. All alias URLs for a resource should redirect to the canonical URL to enforce its authority.


Deep linking

The act of linking to a web resource which is not the homepage of the website being linked to.

Denial of Service (DoS) attack

An electronic attack whose purpose is to prohibit the target server use of a program or an entire system. For example: in a HTTP context it is common for an attacker to bombard a server with many requests until the server is unable to respond appropriately to legitimate HTTP requests.


GET method

A HTTP request method. GET is not an acronym or an initialism, but is capitalised out of convention. The GET method should be used when requesting a resource. See also POST method.


Header field

HTTP header. Multiple headers are sent as part of requests and responses. They are used to send content negotiation information between the server and the user agent (and vice versa).


HyperText Transfer Protocol. A cross-platform open standard communication protocol used to send and receive information on the internet between web browsers and web servers.


POST method

A HTTP request method. POST is not an acronym or an initialism, but is capitalised out of convention. The POST method should be used when sending information to a server or interacting with a web application to change its state.



HTTP request. Every time a user agent requires access to a web resource it performs a request. For example: each web page loaded in a browser will often require several requests are made (one for the page itself and one for each image, script file, or other resource embedded in the page).


HTTP resource. A file or a defined output of an application/database that can be served via HTTP to a user agent. Each unique resource should have at least one unique URL, this ensures the addressability of the resource.


HTTP response. Under normal operating conditions, for each request made by a user agent, a HTTP response will be returned by the server. The nature of the response depends on the request made and the current state of the server, but a common response is to send a status, along with headers and an entity-body containing the requested resource.



HTTP server. Software running on a host computer that listens for incoming requests and responds according to the HTTP protocol. A related term is web server. A web server will almost always act as a HTTP server, but may also support other protocols/functions.


HTTP status. A status code sent with a response to summarise the status of the requested resource. For example: a well known HTTP status is 404, this status is sent by a server when the requested resource cannot be located (or in a few other edge cases). Another common HTTP status is 200, this status is sent by the server when a document is found successfully, and is usually returned bundled with the requested document.



Universal resource locator. A string of characters used to locate a resource available via the Internet.

URL normalisation

The process by which URLs are modified and standardised in a consistent manner. The goal of the normalisation process is to transform a URL into a normalised or canonical URL.

User agent

Software used to access web content. This may be browser software (for end users) or more automated software agent that works on behalf of a person or organisation (example: a search engine indexing robot).


Web application

Software system hosted on a server targeted at human users.

Web service

Software system designed to support interoperable machine to machine interaction over a network. Web services are frequently just Web APIs that can be accessed over a network, such as the internet, and executed on a remote system hosting the service.