Source code

∞Open Rack is free software under the GNU GPL, version 3 or later. Here is the complete corresponding source for the build on this site. It covers our changes, the build scripts, the licences and the third-party library sources, with no sign-up needed.

Downloads for this build (2026-10-30)

File	Size	What it is
open-rack-source-2026-10-30.tar.xz	24.1 MiB	Complete Open Rack source: patched Cardinal tree (only what this build uses), build scripts, licences, written offer
open-rack-thirdparty-deps-2026-10-30.tar.part-00	24.0 MiB	Third-party library sources (unmodified upstream tarballs), part 1 of 4
open-rack-thirdparty-deps-2026-10-30.tar.part-01	24.0 MiB	Third-party library sources (unmodified upstream tarballs), part 2 of 4
open-rack-thirdparty-deps-2026-10-30.tar.part-02	24.0 MiB	Third-party library sources (unmodified upstream tarballs), part 3 of 4
open-rack-thirdparty-deps-2026-10-30.tar.part-03	10.8 MiB	Third-party library sources (unmodified upstream tarballs), part 4 of 4
THIRD-PARTY-DEPS.txt	2.7 KiB	List and checksums of the third-party source tarballs
open-rack-surge-source-2026-10-30.tar.xz	18.1 MiB	Surge XT engine page: Surge XT source (patched), JUCE modules, our bridge and page, build scripts, licences, written offer
open-rack-helm-source-2026-10-30.tar.xz	101.6 KiB	Helm page: Helm engine source, our bridge and page, build scripts, licences, written offer
SHA256SUMS.txt	0.9 KiB	Checksums for every download above
WRITTEN-OFFER.txt	1.0 KiB	Written offer for source code (GPL-3.0 section 6)

The third-party archive is split into parts because of a per-file size limit on this host. To join the parts, download all of them, then run:

cat open-rack-thirdparty-deps-2026-10-30.tar.part-* > open-rack-thirdparty-deps-2026-10-30.tar
sha256sum -c SHA256SUMS.txt --ignore-missing

Build it yourself

tar -xJf open-rack-source-2026-10-30.tar.xz
cd open-rack-source-2026-10-30
./open-rack/build-wasm.sh      # Linux x86_64. Installs Emscripten 3.1.27 via PawPaw, then builds.
# output: bin/CardinalMini.js, .wasm, .data; serve them with open-rack/rack/index.html

Our changes to Cardinal are listed in OPEN-RACK.md and shown in open-rack-changes.diff. They are applied by open-rack/apply-openrack-patches.py, which is inside the archive.

Build the Surge XT engine page

tar -xJf open-rack-surge-source-2026-10-30.tar.xz
cd open-rack-surge-source-2026-10-30
source /path/to/emsdk/emsdk_env.sh   # Emscripten 3.1.27
./build/build-all.sh                 # output: site-out/surge/

Our three small build changes to Surge XT, the bridge code and the patch filter are described in the archive's README.md; licences are in docs/LICENSES.md.

Build the Helm page

tar -xJf open-rack-helm-source-2026-10-30.tar.xz
cd open-rack-helm-source-2026-10-30
source /path/to/emsdk/emsdk_env.sh   # Emscripten 3.1.27
./build/build-all.sh                 # output: site-out/helm/

What we changed and why is described in the archive's README.md; licences are in docs/LICENSES.md.

Licences

∞Open Rack as a whole: GNU GPL, version 3 or (at your option) any later version.
Code and artwork from each module collection keep their own licences, listed in THIRD-PARTY-LICENSES.md (from Cardinal's docs/LICENSES.md).
The new knob, jack and switch artwork and the demo patch are released by The Groovemaster as CC0-1.0.
Written offer for source code. To ask for a copy under that offer, email [email protected].