Jalv (JAck LV2) is a simple host for LV2 plugins. It runs a plugin, and exposes the plugin ports to the system, essentially making the plugin an application. For more information, see http://drobilla.net/software/jalv.
Jalv can be built to run on JACK, where plugin ports are exposed directly as JACK ports, or via PortAudio, where the plugin is connected to the system inputs and outputs.
Jalv is particularly useful as a simple test host for plugin development and testing. It runs plugins from the command line with no user interaction, is light enough to run with tools like sanitizers or valgrind, and is capable of dumping all communication between the plugin and its UI in a human readable format. Plugin UIs can be tested in different host toolkits by using different executables: jalv, jalv.gtk, jalv.gtk3, and jalv.qt5.
-- David Robillard d@drobilla.net