#real-time #synthesis


A library for developing audio plugins and applications, with a focus on software synthesis

3 unstable releases

0.1.1 Aug 28, 2020
0.1.0 May 2, 2020
0.0.1 Jun 14, 2018

#310 in Audio

MIT OR BSD-3-Clause

3.5K SLoC


An API abstraction for API's for audio plugins and applications. Use it to write real-time audio effects, software synthesizers, ... and target different platforms (vst, jack, ...). It is currently most suitable for real-time or "streaming" audio processing. E.g. you cannot use it to reverse audio in time.

Feature matrix

We focus on API's that are typically used for audio effects and software synthesizers. If you want to "just" play audio on various platforms, cpal may be better suited for you.

feature VST 2.4 via rust-vst Jack via jack Offline audio rendering
Full duplex audio input and output
Midi input
Midi output N/A
Sample accurate midi N/A
Multiple midi inputs and outputs N/A
Sampling frequency change N/A
Signal stopping the application N/A N/A
Jack-specific events N/A N/A
Basic meta-data N/A
Access to the underlying host N/A
Parameter changes
GUI stuff


The documentation can be found

  • on docs.rs for the version that is distributed via crates.io.
  • on GitHub pages for the documentation of the master branch
  • on your local machine after running cargo rustdoc --features all


There are full examples in the examples folder in the source code.

Current State

rsynth is in its early stage of development and many changes are breaking changes. The team behind it is very small, so progress is slow.


We try to focus on features that we are actually using ourselves. This helps to ensure that the features that we provide, can actually be used in practice. So if you want to use a particular feature that isn't there yet, feel free to open an issue (if needed) and you can volunteer to test the feature before it is merged.

In the long term, rsynth can be split into multiple crates for maximum re-usability and for license clarity (e.g. when one back-end requires a different license). We're currently keeping everything together because it's easier to coordinate breaking changes over the various components in this way.


Contributions and suggestions are welcome! See CONTRIBUTING.md for more details.


Alexander Lozada's contributions to rsynth are helped by Resamplr.com, a virtual instrument website.


The source code of rsynth is licensed under the MIT/BSD-3 License.

Note: we plan to switch to MIT/Apache 2.0 in a future release.

Note that in order to use rsynth in combination with other crates (libraries), the combined work needs to comply with the license of that crate as well. In particular, the following optional dependencies may require your attention:

  • the hound crate (behind the backend-file-hound feature) uses the Apache license, see its readme for more details