Blue Cat's Plug'n Script
"Craft your own effects and instruments"


Blue Cat's Plug'n Script - Scriptable audio / MIDI effects processor and virtual instrument

Blue Cat's Plug'n Script is a scripting plug-in that can be programmed to quickly build custom audio and MIDI effects or virtual instruments, without quitting your favorite DAW software.

With this plug-in, you can write your own effects with very little knowledge about programming: no need to invest time and money to learn all these plug-in formats, they are all supported here already! If you do not care about programming, Blue Cat's Plug'n Script can also be used as a regular processor with existing scripts or to get someone else write this very particular effect you have been searching for years and cannot find anywhere.

It is also possible for audio software companies to use this plug-in to quickly prototype algorithms and reduce the time required to develop audio products: writing and testing scripts is lightning fast!

This plug-in has been in our lab for several years and has been used to prototype lots of our existing plug-ins. It supports both scripts distributed as source code and pre-compiled binary scripts.

For source scripts, it uses the high performance AngelScript scripting engine, originally developed for video games, with a JIT compiler that helps compiling scripts into machine code for optimal performance. Starting with version 2, the plug-in also supports native (compiled) code and can load binary scripts built from C or C++ (or any language that can export C functions), using the same interface as the angelscript version.

The syntax of the AngelScript language is close to Java, C#, C++ or JavaScript, making it very easy to learn. It is also convenient to reuse your scripts into native code, or integrate code snippets found on the web into your script. Also, switching between angelscript and binary versions of the same script is very easy, requiring very few changes.

The plug-in includes dozens of audio and MIDI processing scripts as well as several virtual instruments and utilities to enhance your workflow. They can be used as is, or as examples to get started to write your own scripts. User scripts can be shared in the scripts repository, which also includes the factory scripts and native projects for reference.

Note: on Mac, the factory native scripts require Mac OSX 10.7 or newer.

To build complex effects chains using multiple scripts, you might be interested in Blue Cat's PatchWork, which can host multiple instances of this plug-in in series or parallel. While writing scripts, you might also want to use our analysis tools to check their effect on the signal.

Mac OS X 10.5+32/64-bit Universal BinaryWindows Vista or newerWindows x64 (64-bit)VSTVST3AAX64-bit AAXAudio UnitRTASDirectX
Price: 79 EUR or $99 (excl. VAT)
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Also in Bundles: All Plugins Pack / Crafters Pack

Typical applications: Audio and MIDI FX scripting, virtual instruments programming, digital signal processing (DSP), Multi-effect processor, algorithm prototyping, learning, plug-in development.


Main Features:

  • Audio and MIDI scripting plug-in.
  • Build your own Audio and MIDI effects or virtual instruments.
  • Simple scripting syntax, using either the AngelScript language (similar to C++, Java or javascript) or C/C++ for native code.
  • Native binary scripts support (compiled C or C++).
  • The user interface adapts to scripts automatically. Build your own using Blue Cat's KUIML language.
  • Up to 48 input parameters and 32 outputs, with full MIDI and automation control.
  • Use your favorite Integrated Development Environment (IDE) for editing.
  • Integrated JIT (Just In Time) compiler for optimal performance (scripts are not interpreted but compiled).
  • Includes 55 scripts with source code and 132 presets for sound synthesis, MIDI FX, audio FX (comp, gate, tremolo echo, filters, looper...), waveform generation, file playback/recording and more.
  • Side chain input and auxiliary outputs support.
  • Surround support (up to 8 audio channels).

Blue Cat Audio Standards:

  • Available as: Mac-AAX, Mac-AU, Mac-RTAS, Mac-VST, Mac-VST3, Win-AAX, Win-DX, Win-RTAS, Win-VST, Win-VST3, Win x64-AAX, Win x64-DX, Win x64-VST, Win x64-VST3.
  • Native DSP code for optimal performance.
  • Full MIDI control and automation support with silent, zipper-free parameters update, advanced response control and MIDI Learn.
  • No CPU load on idle: when the plug-in is fed with silence, the processing smoothly shuts down, to optimize the CPU usage of your Digital Audio Workstation.
  • Skinnable and customizable user interface with transparency management.
  • Automation and MIDI output: record output parameters as automation curves or send MIDI CC messages to other plug-ins for powerful side chain effects.
  • Smooth Bypass: activate/deactivate the plug-in with absolutely no noise.
  • Undo/Redo.
  • Full featured integrated presets manager.
  • Copy/paste the state of the plug-in between instances using the system clipboard.
  • Any sample rate supported.



Click on the thumbnail to enlarge.

Blue Cat's Plug'n Script - 48 scripts and 125 factory presets are included, with multiple audio and MIDI effects and several synthesizers Blue Cat's Plug'n Script - Scriptable audio / MIDI effects processor and virtual instrument Blue Cat's Plug'n Script - Output parameters for audio analysis and parameter modulation Blue Cat's Plug'n Script - Real time MIDI events processing Blue Cat's Plug'n Script - Strings and discrete parameters are also available to control dsp scripts. Blue Cat's Plug'n Script - Write your own Virtual Instruments: included drawbar organ example (additive synthesis). Blue Cat's Plug'n Script - Use your favorite Integrated Development Environment (IDE) for scripts editing Blue Cat's Plug'n Script - Example of script for a tremolo effect

You can find more skins for this product here.

User Comments & Reviews

"Plug'n Script is a very original and powerful piece of software. A simple and intuitive interface, which actually opens a full world of experimentation. Very convenient to prototype new signal processing ideas in seconds. The example scripts are a mine of information, both for audio programmers and beginners. A unique and extremely powerful plugin!" - Charles Verron, Founder -

"An amazing piece of software, it makes possible prototyping new digital signal processing algorithms in a few minutes. And now with the latest version of Plug'n Script, the scripts are running really fast!

Great tool for newcomers who want to familiarize with audio development or for professionnal developers who want to hear quickly what their algorithm sounds like." - Ivan Cohen, Developer - Musical Entropy.

To add your own comment about this product, please contact us.

System Requirements


  • An SSE2-enabled processor (Pentium 4 or newer).
  • Microsoft Windows Vista, Windows 7, 8 or 10.
  • Any DirectX / VST / RTAS / AAX compatible host software (32 or 64 bit).

Mac OS X

  • An Intel processor.
  • Mac OS X El Capitan (10.11), Mac OS X Yosemite (10.10), Mavericks (10.9), Mountain Lion (10.8), Lion (10.7), Snow Leopard (10.6), or Leopard (10.5).
  • Any VST / Audio Unit (32/64-bit) / RTAS / AAX compatible application.

For more information about supported platforms, see our FAQ.

Demo Limitations

  • One single instance of the plug-in per session.
  • The plug-in is regularly bypassed for a few seconds.

Versions History >subscribe to our newsletter

V2.1a (2016/03/04)

  • (VST only) Fixed a crash when loading the VST version in Ableton Live.

V2.1 (2016/03/03)

  • VST3 plug-in format support, with improved external sidechain compatibility for Cubase and Nuendo.

V2.0 (2015/11/25)

  • External side chain and auxiliary outputs support (up to 16 audio outputs).
  • Native C/C++ scripts support for optimal performance and flexibility.
  • KUIML 2.0 user interface language support to build custom user interfaces, with additional scripting capabilities.
  • New DSP scripts, delivered with full angelscript and C++ source code.
  • 21 new custom skins included.
  • User documentation (html or pdf) can now be added to scripts.
  • Custom skins can be selected directly from the main menu.
  • Presets can now be selected using MIDI Program change and bank select messages (can be activated with the presets menu/MIDI Program Change item).
  • Last loaded preset can now be saved directly from the presets menu without having to select the file.
  • VST: fixed latency compensation reporting in Cubase (no need to re-enable the plug-in to update the latency anymore).

V1.1 (2014/10/01)

  • Audio Unit can now be loaded as a MIDI effect in Logic Pro X.
  • The user interface now displays switch buttons for boolean parameters instead of knobs.
  • Discrete parameter values can now be selected from a dropdown menu.
  • New API: scripts can now use plain strings as user input.
  • New API: scripts can now read and write files.
  • New scripts and presets: added audio player and recorder scripts and a wave file utility class.
  • Developers can now share their scripts on a dedicated GitHub repository.
  • Fixed: implemented pass-thru for MIDI events when no processing function is declared (default script for example).
  • Fixed: Audio Unit Synth version did not appear as an Instrument.
  • Fixed: script was reloaded when starting playback in Reaper, and the effect was not applied immediately.
  • Fixed: RTAS version could freeze Pro Tools 9 and earlier at startup.

V1.0 (2014/09/18)

First release.