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 RapidComposer by MusicDevelopments is a Virtual Instrument Audio Plugin and an Audio Plugin Host and a Standalone Application. It functions as a VST Plugin and a Standalone Application. It can host VST Plugins.
RapidComposer RapidComposer RapidComposer RapidComposer RapidComposer
Product RapidComposer
Developer MusicDevelopments
Price (MSRP)
Type / Tags Music PrototypingAlgorithmic Melody GeneratorChord GeneratorChord LibraryMusic ComposingMusic Prototyping
Plug-in, App & Soundware Format(s)
Can Host
Operating System Availability
Download Released
Downloads Released
System Requirements
•Supported operating systems: Windows Vista/7/8/10 (32-bit or 64-bit)
•Intel/AMD processor 1.4 GHz minimum
•512 MB RAM
Downloads Released
System Requirements
•macOS 10.9-10.15 (latest update)
•Intel Core Duo minimum
Supported Sample Formats (loads or saves) include
AIFF, SF2 (SoundFont), WAV
Miscellaneous Information
Copy ProtectionSerial Number

RapidComposer is a rapid music prototyping software designed for composers, song-writers and musicians of all musical styles.


  • Unique non-destructive, phrase-based music composition.
  • Advanced tools for phrase editing, phrase morphing, phrase generation, phrase grouping, motif development, chord progression editing.
  • Chord suggestions, chord progression generation, chord progression rules editing.
  • Melody generation, melody harmonization.
  • Timeline with chords (absolute or chord functions) which all phrases automatically conform to.
  • Piano roll with scale notes, visually editable chord notes, and smart arranging of overlapped notes in two styles.
  • In-place non-destructive phrase-level and note-level editing.
  • Sophisticated MIDI CC editing and recording.
  • Articulations can be assigned to phrases or even individual notes.
  • Extensive scale, chord, guitar chord, chord progression databases.
  • Movable, resizable and transposable smart phrases that always conform to the current chord.
  • Phrase and rhythm generators help you to create thousands of musically useful (not random) phrases.
  • Taggable instrument database of all MIDI, VSTi and SF2 presets in one place.
  • Variations can be applied to phrases, or whole tracks.
  • IdeaTool that can generate a multitrack composition based on the provided parameters and rules.
  • Intuitive drag and drop environment (you can drop chords, progressions, phrases, instruments to the composition).
  • Fully customizable user interface with preset themes.
  • Unlimited undo and the ability to make several versions of the same composition.
  • MIDI drag-and-drop tracks or composition to DAWs.
  • Virtual instruments (VSTi v2.4 plug-ins) support.
  • SoundFont (.SF2) support.
  • Standalone and VST version (32-bit and 64-bit).
  • Available for Windows and Mac OS X.
Latest User Reviews Average user rating of 5.00 from 1 review

Reviewed By tommyzai
June 3, 2013

RapidComposer v3 by MusicDevelopment is an inspiring music composition tool.

The purchase, download, install, and authorization process is simple. There are no annoying protective devices needed. Upon initial launch, users will notice a redesigned sleek, flat, modern GUI with color in just the right places. My eyes are fried from years of eMusic and normally twitch after a few minutes of screen time, but not with the new version of RapidComposer. It's quite calming and comfortably compelling. Buttons are presented in 3D and/or have a slight shadow effect, making the interface easy on the eyes and inviting to use. I realize this software is designed for both Windows and Mac operating systems, but at the risk of annoying PC users — RapidComposer v3 is very Apple-like in appearance and feel. I consider that a good thing — very few complain about the look of Logic and Garageband! If the look does not suit the users taste, the color scheme is completely customizable. Overall, the arrangement of items throughout the interface helps to create a simple, effective, enjoyable workflow.

RapidComposer has accurately been called,"composer-friendly." When I first installed v2, I was an original eMusician trying to get back into the biz after many years away. Whoa! Things really changed. Nowadays almost anything is possible on a laptop. Yet, each year, creating music on a computer has become more and more complex. The gap between idea and song has never been wider. It's so easy to get tangled inside a web of options. Enter RapidComposer! Once you understand that RC is not a DAW, but something unique — it's really fast! I dig the workflow and the features. When it comes to creating music, I'm a visual guy, and this is a very visual audio application. RC is also educational. Users will greatly improve their understanding of music theory without realizing they were studying. It's a sneaky little app that will help users become better musicians, producers, and composers. RapidComposer has a moderate learning curve. It's a deep program with tons of flexibility and creative options. I would develop carpel tunnel syndrome before I could complete a comprehensive review of all the things this app does, so I'll highlight a few of the groovier features:

Phrase Generators are found inside one of the six composition tab icons (Scales, Chords, Progressions, Phrases, Rhythm, Variations, Instruments). I discovered this cool component after watching a video tutorial by Chris Caulder. He created an excellent, easy to watch series: https://www.youtube.com/watch?v=gGMnvWLf5KY. Instead of rehashing Chris' words, check out the first two parts of his tutorial. That should be enough to spark your interest. Speaking of tutorials, there are also many user videos available on the MusicDevelopments website: http://www.musicdevelopments.com/videos2.html.

One of the coolest features of RapidComposer is its ability to harmonize the user's original melody. I have a knack for coming up with melodies, but I'm terrible at selecting chords and determining a chord structure for my tunes. Luckily, RapidComposer is there to help. According to a fellow RC user,"Harmonizing melodies works beautifully (according to the selected Chord Rules)." For more on Melody Harmonization, go to:


Another amazing feature of RapidComposer is its ability to import and convert Standard MIDI files into RC phrases. This is an extremely powerful feature that allows users to construct a large library of phrases for later assembly into songs. This feature is reminiscent of Apple loops, which are stored in a loop library for drag-n-drop into audio tracks.

• Clean, modern, customizable GUI (colors, button shapes, borders and shading) with preset themes
• Small footprint (57MB)
• MIDI drag 'n drop in and out of DAWs
• Excellent chord detection
• MIDI parts called "phrases" are used almost like audio loops, but MIDI data (chords, notes, etc.)
• Powerful Phrase Editor (generation, morphing, chord progression, etc.)
• Multi track composition with a button to randomize creative patterns
• Ability to create personal a Progression and Rhythm database
• Wonderful Chord Suggestion function
• Ability to create/save/use Chord Rules
• Deep database with lots of chords, progressions, scales, MIDI, etc
• CPU efficient
• Stable (I have never had issues with v2 freezing or crashing, but others have. That being said, the new version has been very stable)
• Friendly customer support via forums and website
• Responsive developer — reacts quickly to inquiries and feature requests; lots of updates.

Note: After extensive demoing and research, I ran my findings by a much more experienced RapidComposer user. According to Yıldırım,"Importing MIDI files and building a custom Phrase Library are [vital] features that require a little more experience to use effectively, but they are well worth mentioning."

Keyboard shortcuts can now be customized. With the new version, the Idea Tool is integrated into the main composition workspace. The Rhythm Browser is quite handy. It allows rhythms to be dragged from one phrase to the other or from the Rhythm Browser to Phrases. Rhythm Editing is greatly improved and includes new variations. There is also a new Rhythm Generator (Euclidean) and a new Phrase Generator (Arpeggiator).

• MIDI Event Editor
• Although audio tracks can be added and appear like phrases, they are limited to 16-bit. According to the developer, there is a plan to update audio support in the near future.

RapidComposer is a remarkable composition tool for musicians. It's often classified as a sequencer, which is technically accurate, but it's so much more! To quote another user,"The potential of this program is VAST." There are many cool built-in features and tricks designed to help musicians, producers, and songwriters compose songs. It's not meant for mixing and mastering — that's what your DAW does. This thing is for sketching out stuff, and it does it really well. It cost a couple hundred dollars, which IMO is money well spent. I am excited to be creative again. Two thumbs up and a big virtual hug. Thank you MusicDevelopment for developing this fantastic creative environment.

*Rating Disclaimer: In all fairness and honesty I would rate this wonderful product at least a 9.5, but 9 would be an insult, so I went with 10. I'm sure it will be worthy of a 10 by the next big update anyway! :-).

Read more


Discussion: Disabled
6 June 2013 at 12:18am

Where are the (three) YouTube videos Chris was planning to produce ??

- atonal.

7 June 2013 at 7:13am

It sounds cool. Same thing on Windows ?

12 June 2013 at 2:45pm

Well all I can say about it was that (on my venerable iMac running snow leopard) the demo version kept crashing before I could see what it was about .....

1 July 2013 at 6:32pm

Pretty damn crashy on my Win8 laptop.

Luckily it autosaves before it crashes.

3 August 2013 at 11:36pm

Hi tommyzai, I agree with you concerning the concept of this software, but sadly rapid composer is unusable for me, buggy as hell, unstable...c'ant use it more than 5 min without problems! I have seen you are on Mac like me, please can you tell me what OS you use? I' m on mountain lion my computer is a Mac book pro quad core I7 end 2011. My vote is 10 for the concept and 2 for the reliability...

Best Regards.

1 April 2016 at 4:42am

Hi Chandran, I am so sorry I never replied to you. I had notifications turned off by mistake. I just happened to peek at my user review and found your inquiry. I hope the latest update of RC is running smoother for you. I have not had many freezes or crashes, and I've used it from Snow through El Capitan. I also have a i7 2011, but a MacBook Pro. It could be a conflict with other things, or I've just been lucky. Others have mentioned instability with early versions of RC. Hopefully, whatever it is. .. it's now fixed. It's a cool app and very useful. Tommy.

12 December 2013 at 7:27pm

Yes, it does seem a bit unstable. I sent an email with bugs I found, and Attila seems very keen on perfecting his software.. Just keep saving... Logic went thru quite a 'buggy' stage at one point (years ago). I'm using a MacPro 2008 (intel) OS X 10.7.5.

6 May 2014 at 12:57am

The manual on page 6 says: "CUSTOM MIDI FILES, SAMPLE COMPOSITIONS, and AUDIO SAMPLES are available for download for Demo & Registered versions.

Where exactly are these?

7 May 2014 at 8:57am

This is not too exact in the manual. The sample compositions can be found in the program as templates (click on the 'Using' menu next to 'New Composition').

Registered users get about 250 very usable phrases, and you can find hundreds of additional phrases on the support forum here at KVRAudio that can be used in the demo version as well. These are mainly strings staccato and piano phrases.

If you want to listen to songs created with RapidComposer, you will find them in this topic:


7 May 2014 at 12:43pm

Thanks for the quick response. After finding this forum and seeing it so un-used I was about to write RapidComposer off. I did find the link you provided (before you sent it), and after listening to songs I realized I really want to check RapidComposer out.

Just a suggestion ... in the kva forum there was no indication that I was actually in a forum about RapidComposer until I got into some posts. I would suggest that somewhere in the forum headers you make if obvious which areas are about RapidComposer. Once you know it if's find but for newbee's ... they might miss out on checking RapidComposer out.

7 May 2014 at 3:32pm

Yes, purposed to the visitors and the newbyes, simply change the header of the forum.

from "musicdeveloments"

to "MusicDevelopments RapidComposer"

would be an excellent idea to better identify the forum.

(who composes now exclusively on RapidComposer since last december)

7 May 2014 at 4:27pm

You are both right, but I cannot change the forum title because that should be the company name...

7 May 2014 at 3:56pm

Yes, this discussion is not really used. The open support forum has lots of interesting topics:


In addition some comments here are outdated, e.g. the OS X version is very solid now. The work on RapidComposer is continuous, bugs are fixed in very short time, and the forum is full of creative people. Registered users can try the latest beta version and use features weeks before the release.


5 May 2016 at 9:51pm

I just wrote a new user review based on the beta of v3. I hope users and potential users find my words useful.

5 May 2016 at 11:17pm

Very good review, Tommy! I would have added just another point at the end: Attila, the developer, is one of the kindest and of the most communicative guys in the world, and present IN PERMANENCE within his beta testers to have the most reactive returns and the best way to make the tool enhance permanently. Remarks, alerts, suggestions, engine, harmony rules, GUI... everything is discussed all together (and always in the best ambiance) to help Attila in his wonderful but very hard work. A bug found during the beta tests and confirmed by another tester or by Attila is generally fixed within the next days when not in the next hours! And we are a very active and a very enthusiast team around him. In my opinion, RapidComposer is now for the piano-roll what Sibelius or Finale are for the classical score writing, and nobody has gone as far as Attila in the quality concerning piano-roll writing and in the incredible sum of features to compose for the modern music as well as for the classical music, jazz music, rock music, ambient and chillout music, ethnic music (even for Asian, Indian, African, Arabic scales), songs, etc. Not only composing with RapidComposer is a true pleasure but contributing to his team of testers is one of the most pleasant times I have known in my life, now close to 60 years.

BlackWinny, who composes EXCLUSIVELY with RapidComposer since December 2013, the tool being used simply as a VST in my DAW to drive at its outputs all my instruments, each one on its MIDI channel.

5 May 2016 at 11:38pm

I'm honored to join such an amazing team of dedicated users.

6 May 2016 at 1:52am

Another decently-written review. It looks like we use some of the same music programming tools, despite being users of different platforms: you on OS X, and I on Windows.

6 May 2016 at 2:26am

tonedef71, thanks for appreciating my efforts. We're in it together. .. using tools to compose. .. looking for a better way.

6 May 2016 at 3:29am

Indeed. I couldn't have said it better myself. :)

Discussions have been disabled for this item.


Average user rating of 5.00 from 1 review

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