Xvfb

Start virtual display

$ Xvfb :99

$ Xvfb :99 -screen 0 [1920x1080x24]

$ Xvfb :1 -screen 0 [1280x1024x24] -screen 1 [800x600x16]

$ Xvfb :99 -shmem -screen 0 [1024x768x24]

$ Xvfb :99 -fbdir [/tmp/xvfb]

$ xvfb-run -a [application]

$ xvfb-run -s "-screen 0 1280x1024x24" [application]

Xvfb [:display] [options]

Xvfb (X Virtual FrameBuffer) is an X server that performs all graphical operations in memory without any physical display. It implements the X11 protocol, allowing X applications to run without visible output.
Common use cases include running GUI applications on headless servers, automated testing of graphical applications, rendering graphics for web services, and CI/CD pipelines that require X applications.
The xvfb-run wrapper script simplifies usage by automatically selecting a display number and handling authentication.
Default screen configuration is 1280x1024x24 (width x height x depth in bits).

:display

Display number (default: 0).

Configure screen: number, width x height x depth.

Additional pixmap depths to support.

Directory for memory-mapped framebuffer files.

Use shared memory for framebuffer.

Adjust line pixelization.

Set black pixel value.

Set white pixel value.

-a, --auto-servernum

Find available display number automatically.

Arguments to pass to Xvfb.

File to store Xvfb error output.

Authority file to use.

Server number to use.

No GPU acceleration. Some applications may behave differently without real display. Memory usage scales with screen size and depth. Applications expecting specific display features may fail.

Xvfb has been part of the X.Org server distribution since the X11R5 release. It was developed to enable X applications to run on systems without display hardware, supporting server-side rendering and automated testing long before headless browser technologies.

X(7), Xserver(1), xvfb-run(1), xdpyinfo(1)