Jalv is a simple but fully featured LV2 host for Jack. It runs LV2 plugins and exposes their ports as Jack ports, essentially making any LV2 plugin function as a Jack application.

Jalv is a small program which is useful, but also intended to be an appropriate test host for plugin development. It runs plugins from the command line with no user interaction, is light enough to run in valgrind, and is capable of dumping all plugin to/from UI communication in a human readable format.

For testing with various host toolkits, there are several Jalv executables: jalv, jalv.gtk, jalv.gtkmm, and jalv.qt. The jalv and jalv.gtk programs are suitable for production use by users, the others are less complete and intended for developer testing only.


The latest version of Jalv is 1.4.6, released on August 08, 2014.



Jalv is developed and given away freely for the benefit of all. However, donations of appreciation for the considerable time and effort spent are appreciated:


20 thoughts on “Jalv

  1. Pingback: Jalv 1.0.0 | drobilla.net

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  3. Pingback: Jalv 1.2.0 | drobilla.net

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  6. Pingback: Jalv 1.4.0 | drobilla.net

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  8. Pingback: Jalv 1.4.4 | drobilla.net

  9. Jack session (and LADISH, because it supports JACK session) has this feature where it can tell the application to save its state in a particular location. Is Jalv able to save the LV2 plugin settings in a location specified by the session manager and then load them later, from a location specified from the session manager?

  10. Hi David ; I’m currently working with a DAW that is only LADSPA and (GNU/Linux) VST compatible. I told the author about LV2, and he seemed to say that LV2 implementation is very complicated. Could Jalv be a starting point towards said implementation?

    • It deliberately serves as a simple example host, anyway. The core of it, jalv.c, is less than 1000 LOC, and that includes all the Jack client stuff. Some of the fancier things are a little bit more work, but you can find simple relatively reusable implementations of the most important stuff in Jalv as well.

      The currently poor design of http://lv2plug.in/ tends to suggest that implementing LV2 is much harder than it actually is.

  11. Pingback: Jalv 1.4.6 | drobilla.net

  12. Hello. I can’t found answers in help.

    1. How I can set specific JACK-client name for Jalv instance?
    2. There’s any way to control knobs of Jalv instance in realtime (from another application, not by my bare hands)?

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