New Audio Plugin Standard, CLAP, Offers Open Source Alternative To VST & AU

Bitwig and u-he have announced CLAP (CLever Audio Plug-in API), a new open standard for audio plug-ins and hosts.

CLAP offers modern features, innate stability, and rapid support for plug-in and host developers. The developers say that, since it’s open source and liberally licensed, CLAP is a safe bet for the future.

CLAP 1.0 is the result of a multi-year project initiated by u-he and Bitwig, with design and implementation contributions by a group of commercial and open source audio developers.

Here’s are the benefits that the developers highlight:

Better Performance From Modern CPUs

Developed with modern CPUs in mind, CLAP takes multi-thread management to a new level, with a clear and efficient allocation of roles between plug-in and host. Specifically, CLAP allows collaborative multicore support between plug-in and host through a so-called “thread-pool”, also allowing hosts to manage CPU-threading for plug-ins that provide their own multicore support. Preliminary tests show significant performance gains compared with current solutions.

Better and Faster Organization

CLAP hosts can read plug-in metadata and help organize your plug-ins. As CLAP hosts can retrieve information from plug-ins without having to wait for them to initialize, plug-in scans can be much faster.

The developers say that they’re also finalizing an extension that will let plug-ins tell the host which files they need (e.g. samples or wavetables), so the host can consolidate those in the project file. That means you’ll never lose a sample while transferring a project between systems.

Better Modulation

The CLAP standard promotes new ways to create music with automation, modulation, and expressions:

  • CLAP supports per-note automation and modulation (in accordance with the recent MIDI 2.0 specifications).
  • CLAP’s parameter modulation concept also allows for temporary parameter offsets. Parameter modulation is non-destructive, so as soon as the modulation has finished, the target parameter will return to its original state.
  • CLAP makes it possible for polyphonic plug-ins to have their per-voice parameters modulated for individual notes (“MPE on steroids”).

Initial implementations by Bitwig, u-he and the Surge project demonstrate CLAP’s possibilities.

Information for Plug-In and Host Developers

The CLAP creators tout many benefits for plug-in and host developers:

“From the C-only ABI, which allows binding to any programming language, to the transparent client-server model between host and plug-in, the robustness and clarity of the threading model, and the single event queue for all kinds of parameter changes, timing and MIDI. Despite being so comprehensive, everything in CLAP is easy to find and easy to implement.

A single cpp/hpp glue layer for C++ offers a quick start into the ABI, and its built-in “proxy layer” finds common threading bugs in an instant. Apropos C-only ABI: There are no platform specific dependencies: In theory CLAP should also run well on embedded platforms, game consoles or specialized supercomputers.”

Open Source & Liberal License

CLAP is open source, released under the MIT license: No fees, memberships or proprietary license agreements are required before developing or distributing a CLAP capable host or plug-in, and the license never expires.

In a nutshell, there are no entry hurdles for developers, and plenty of open source projects already benefit from CLAP.

It’s available now via Github.

MIDI Just Works

Inspired by MPE and MIDI 2.0, CLAP can adapt to any future MIDI standard. Wherever a solid standard exists, we allow developers to freely decide how to apply it. Plug-ins can receive and send any MIDI event on multiple ports.

Extensibility & Governance

A simple system for extensions makes CLAP future-proof. Companies can offer proprietary extensions if required for specific features.


CLAP is now available in the latest Bitwig Studio beta version and in the u-he CLAP beta versions of ACE, Diva, Hive 2 and MFM2.5. It has also been implemented by Chowdhury DSP, MultitrackStudio and the Surge Synth Team.

Open Source Projects Using CLAP:

Avendish project
CLAP JUCE Extensions project
MIP2 framework
nih-plug framework
TheWaveWarden (Odin2

Following companies and projects are already evaluating CLAP for their host and plug-in software:

Epic Games (Unreal Engine)
Expressive E
iPlug2 framework
LHI Audio
Node Audio (Etonal Studio)
Togu Audioline
Valhalla DSP
Vital Audio
Xfer Records

27 thoughts on “New Audio Plugin Standard, CLAP, Offers Open Source Alternative To VST & AU

  1. Finally, the world can stop providing free advertising for Steinberg every time the three-letter acronym for the technology is used!

  2. I currently use 4 Daws – Logic, Cubase, Live and Reason. The only one out of this bunch that might adopt this new format is Ableton but it’s unlikely since they already support both VST and AU.

  3. The now kinda defunct VSTplanet website (thanks for that, Steinberg!) will rise again and will be reborn as CLAPplanet [dot] net.

    (At least I hope so… wishful thinking on my part of course! It just would be so nice for the freeware plugin community.)

  4. Reading between the lines here, if Epic Games (Unreal…& bandcamp) started plugin and producer orientated product stores and/or developer partnerships, the potential for fire-hosing of “free” stuff has my palms twitching.

  5. It was great to see that Vital and Surge got on board quickly.

    One DAW that has got on board very quickly is Giel Bremmers’s MultitrackStudio. It is a versatile, affordable, no-nonsense DAW that has continually evolved due to a dedicated developer who really listens and responds to users. Though it isn’t like Logic are other biggies, it’s quite useable.

    1. Damn, I’ve been looking for a straightforward and lightweight sysex-capable, patch and controller mappable, external MIDI-friendly editor that I don’t have to run in WINE on mac for a while. Thanks for mentioning this, I just found my new fav tool 🙂

      1. Oh, I’m so glad. It really is an under-rated, under-the-radar DAW. I should mention there is an equally capable iOS version, that is perhaps the best iOS DAW there is, especially when it comes to flexible rhythm, MPE, and other important things.

        I guess that raises the question as to whether some iteration of CLAP could work for iOS to replace AUv3

    1. You’ve not said much. Your comment is not self-explanatory (except in your own mind).

      A waste of time because? It won’t work? It doesn’t do what you want? It will never take off? You don’t understand things?

  6. its a good idea because the core VST tech is like 20 years old at this point, and this kind of software could definitely benefit from code based on modern technology

    unfortunately im not really focusing on the software side much anymore, so its not a big deal to me… but ultimately the industry will have to evolve sooner or later

  7. Cockos and Presonus. Well it doesn’t look very promising, all the giants are not backing up as it seems at the moment and neither are the more niche companies.

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