Headless software (e.g. "headless Java" or "headless Linux",) is software capable of working on a device without a

graphical user interface The GUI ( "UI" by itself is still usually pronounced . or ), graphical user interface, is a form of user interface that allows User (computing), users to Human–computer interaction, interact with electronic devices through graphical icon (comp ...

. Such software receives inputs and provides output through other interfaces like network or

serial port In computing, a serial port is a serial communication interface through which information transfers in or out sequentially one bit at a time. This is in contrast to a parallel port, which communicates multiple bits simultaneously in paralle ...

and is common on servers and

embedded device An embedded system is a computer system—a combination of a computer processor, computer memory, and input/output peripheral devices—that has a dedicated function within a larger mechanical or electronic system. It is ''embedded'' a ...

s. The term "headless" is most often used when the ordinary version of the program requires that a

graphics card A graphics card (also called a video card, display card, graphics adapter, VGA card/VGA, video adapter, display adapter, or mistakenly GPU) is an expansion card which generates a feed of output images to a display device, such as a computer mo ...

or similar graphical interface device be present. For instance, the absence of a graphic card, mouse or keyboard may cause an initialization process that assumes their presence to fail, or the graphics card may be relied upon to build some offline image that is later served through network. A

headless computer A headless computer is a computer system or device that has been configured to operate without a monitor (the missing "head"), keyboard, and mouse. A headless system is typically controlled over a network connection, although some headless system ...

(for example, and most commonly, a server) may be missing many of the system libraries that support the display of graphical interfaces. Software that expects these libraries may fail to start or even to

compile In computing, a compiler is a computer program that Translator (computing), translates computer code written in one programming language (the ''source'' language) into another language (the ''target'' language). The name "compiler" is primarily ...

if such libraries are not present. Software built on a headless machine must be built within command line tools only, without the aid of an IDE.Michael Wiles (2010)
Headless Build, who needs it?

Headless websites

Next to

s and headless software, the newest form of headless technology can be found in websites. Traditional websites have their own back-end and front-end (

). All the pieces work with the same code base and communicate directly with each other, making the website as a whole. However in a headless installation the front-end is a stand-alone piece of software, which through

API An application programming interface (API) is a way for two or more computer programs to communicate with each other. It is a type of software interface, offering a service to other pieces of software. A document or standard that describes how ...

communicates with a back-end. Both parts operate separately from each other, and can even be placed on separate servers, creating a minimum version of a multi-server architecture. The bridge between both parts is the API client. The endpoints of the API are connected to each other. The biggest advantages of this technology can be found in performance optimisation and flexibility of the software stack.

References

Software engineering terminology

Headless websites

See also

References