A free and open-source digital audio workstation, written in Rust.

Overview · Capabilities · Getting started · Architecture · Roadmap · Contributing · Community · License

Overview

Lemon Studio is a pattern-based music production environment: build patterns in a step sequencer and piano roll, arrange them on a playlist, and mix them through a routable mixer. It is written from the ground up in Rust, with a sample-accurate audio engine, a fast CPU-rendered interface and hosting for CLAP, VST3 and VST2 plugins.

Lemon Studio runs on Windows, Linux and macOS, and every change is built and tested on all three. macOS is supported at the same level as Linux; the few differences are listed in the macOS notes.

A central goal is interoperability: Lemon Studio opens and saves FL Studio projects (.flp). The project reader is built to round-trip: anything in a file that Lemon Studio does not understand yet is kept and written back unchanged, so a project survives being opened and saved. This support is still young, so read the warning below before trying it on real work.

[!WARNING] Lemon Studio is pre-alpha software. It is under active development and is not yet a usable DAW: expect missing features, rough edges and breaking changes.

• Greyed-out controls are not implemented yet. Many menus and buttons are already laid out but do nothing so far; they are drawn dim and say "not available yet".
• No prebuilt binaries will be published until Lemon Studio reaches a usable state. Until then it can only be built from source.
• Projects saved by FL Studio 10 or later open (25 and 26 included). Projects older than 24.2 are converted to the current layout as they open and are saved in it, so the version that wrote them may not read the saved copy.
• Project-file support is at a very early stage. Do not overwrite your original .flp projects with files saved by Lemon Studio until this support is declared stable. Work on copies and keep backups.

Capabilities

Where Lemon Studio stands against what a complete DAW offers:

✅ usable · 🚧 partial · ❌ not available yet

ASIO is a registered trademark of Steinberg Media Technologies GmbH.

Piano roll: chords and a melody with their note names, and the velocity lane below	Song arrangement: pattern, audio and automation clips under section markers

Per-area details are in docs/status.md. The full, item-by-item roadmap lives on the Discord server.

Getting started

No prebuilt binaries are provided at this stage: Lemon Studio is built from source. Each platform below goes from a fresh machine to Lemon Studio installed with its icon, and Lemon Studio's own plugins installed for any DAW. All three need Rust, stable toolchain 1.89 or newer, installed through rustup, and a clone of this repository:

git clone https://github.com/ItsAlphaNeon/Lemon-Studio.git
cd Lemon-Studio

cargo run -p os-app --release builds and runs Lemon Studio. Before Lemon Studio starts, it also rebuilds Lemon Studio's own plugins (Lemon Sampler, Lemon Trio, Lemon Parametric EQ, Lemon Limiter, Lemon Reverb, Lemon Delay, Lemon Soft Clipper, Lemon Fast Distortion, Lemon Balance, Lemon Stereo Enhancer, Lemon Transient Processor, Lemon Chorus, Lemon Stereo Shaper, Lemon Filter, Lemon Flanger, Lemon Phaser, Pulp Filter, Press, Tesla and Citrus) and installs the ones that changed as VST3 and CLAP plugins, in the folders where other DAWs find them. Lemon Studio itself has every one of them built in and needs no plugin files. A plugin that is new or updated in the repository shows up in other DAWs at the next run. The first run builds every plugin, which takes a few minutes more; later runs rebuild only what changed. Set OPENSTUDIO_NO_PLUGIN_BUILD=1 to skip the plugin build. A Lemon Studio installed as below builds nothing: after pulling changes, either run the command above once, or build and install only the plugins with cargo run -p bundle-plugins -- --install.

Windows

Windows 10 or 11, x64.

Prerequisites

• The Microsoft C++ build tools that Rust uses (rustup offers them when it installs; otherwise the Visual Studio Build Tools with the "Desktop development with C++" workload). They include the Windows SDK, which embeds the application icon in the program; without the SDK the build still succeeds, without the icon.
• LLVM, whose libclang generates the time stretcher's and the ASIO SDK's bindings at build time: winget install LLVM.LLVM. If libclang.dll is not in LLVM's default folder, set LIBCLANG_PATH to the folder that holds it.

Build and run

cargo run -p os-app --release

Install lemonstudio.exe, with its icon, into %USERPROFILE%\.cargo\bin, and give it a Start menu entry (from there it can be pinned to the taskbar):

cargo install --path crates/os-app
$link = (New-Object -ComObject WScript.Shell).CreateShortcut("$env:APPDATA\Microsoft\Windows\Start Menu\Programs\Lemon Studio.lnk")
$link.TargetPath = "$env:USERPROFILE\.cargo\bin\lemonstudio.exe"
$link.Save()

Plugins: cargo run -p os-app --release installs Lemon Studio's plugins in %LOCALAPPDATA%\Programs\Common\VST3 and ...\CLAP, where DAWs find them. To build and install them without starting Lemon Studio, run cargo run -p bundle-plugins -- --install.

Notes

• A plugin that crashes is stopped (its slot passes the sound through) instead of closing Lemon Studio.
• lemonstudio.exe is a Windows GUI program: started from Explorer, the Start menu or a shortcut it opens no console window. Under cargo run its output goes to the terminal as before. Started directly from a terminal it prints there too, but the terminal does not wait for it: for --render, add | Out-Default in PowerShell (or use start /wait in cmd) to wait until the render is done.
• Settings, themes and presets live in %APPDATA%\Lemon Studio. OPENSTUDIO_USER_DIR overrides the folder.
• Plugins are found in %LOCALAPPDATA%\Programs\Common\{VST3,CLAP}, %COMMONPROGRAMFILES%\{VST3,CLAP} and CLAP_PATH, plus any folder added in Settings > Plugins. VST2 plugins are found in the folder their installers record (HKEY_LOCAL_MACHINE\SOFTWARE\VST, VSTPluginsPath) and in those of %PROGRAMFILES%\VSTPlugins, %PROGRAMFILES%\Steinberg\VSTPlugins, %COMMONPROGRAMFILES%\VST2 and %COMMONPROGRAMFILES%\Steinberg\VST2 that exist. 32-bit VST2 plugins cannot be loaded: they are listed as not supported, without being tried.

Linux

x64, on X11 or a Wayland desktop.

Prerequisites: a C++ compiler and libclang (for the time stretcher), the ALSA and JACK development files (JACK itself is loaded only when JACK mode is chosen), the Wayland development files (which Lemon Sampler's file dialogs link against when it is built as a plugin) and pkg-config:

# Debian / Ubuntu
sudo apt install g++ libclang-dev libasound2-dev libjack-jackd2-dev libwayland-dev pkg-config
# Arch (pipewire-jack or jack2)
sudo pacman -S gcc clang alsa-lib pipewire-jack wayland pkgconf
# Fedora
sudo dnf install gcc-c++ clang-devel alsa-lib-devel pipewire-jack-audio-connection-kit-devel wayland-devel pkgconf-pkg-config

For the "save changes?" prompt, zenity or KDE's kdialog (a stock KDE desktop has the latter).

Build and run

cargo run -p os-app --release

Install lemonstudio into ~/.cargo/bin (which must be on your PATH), with its icon and an entry in the application menu (the desktop entry also names the icon under native Wayland):

cargo install --path crates/os-app
install -Dm644 crates/os-app/assets/lemonstudio.png ~/.local/share/icons/hicolor/256x256/apps/lemonstudio.png
install -Dm644 crates/os-app/assets/lemonstudio.desktop ~/.local/share/applications/lemonstudio.desktop

Plugins: cargo run -p os-app --release installs Lemon Studio's plugins in ~/.vst3 and ~/.clap. To build and install them without starting Lemon Studio, run cargo run -p bundle-plugins -- --install.

Notes

Lemon Studio runs on X11, and on Wayland desktops through XWayland. Plugin editors on Linux are X11 windows, and an X11 window cannot sit inside a native Wayland one; with the main window on X11 too, plugin windows dock inside it as on Windows (or detach, from their window menu). A few things differ from Windows for now:

• Native Wayland is used only when there is no X server, or when OPENSTUDIO_WAYLAND=1 is set. Plugin windows are then always separate windows, kept above Lemon Studio while it is the active application; their window menu, Presets list and Misc lists do not open, and files cannot be dropped in from a file manager (the windowing library does not support it there).
• Scaling: under XWayland Lemon Studio follows the X11 scale (Xft.dpi). If it looks soft on a fractionally scaled Wayland desktop, let X11 applications scale themselves (KDE: Display Configuration > Legacy applications (X11) > Apply scaling themselves).
• Keys pressed while a plugin's editor has the keyboard focus do not play the typing keyboard yet, and a sample dragged from Lemon Studio's browser onto a plugin window does not reach the plugin yet.
• Lemon Sampler cannot copy or paste audio through the clipboard yet.
• Settings, themes and presets live in $XDG_CONFIG_HOME/Lemon Studio (usually ~/.config/Lemon Studio). OPENSTUDIO_USER_DIR overrides the folder.
• Plugins are found in ~/.clap, /usr/lib/clap, /usr/local/lib/clap and CLAP_PATH, in ~/.vst3, /usr/lib/vst3 and /usr/local/lib/vst3, and in VST_PATH (else ~/.vst, /usr/lib/vst, /usr/local/lib/vst and the lxvst folders that exist) for VST2, plus any folder added in Settings > Plugins.

macOS

macOS 11 or newer. macOS is supported at the same level as Linux, with the same features, and continuous integration builds and tests every change on macOS alongside Windows and Linux.

Prerequisites: the Xcode Command Line Tools, which bring the compiler and libclang: xcode-select --install. Xcode itself is not needed (only to regenerate the app icon, see tools/logo/macos-icon.sh).

Build and run

cargo run -p os-app --release

Install Lemon Studio as an app, Lemon Studio.app in ~/Applications, with its icon: it opens from Launchpad, Spotlight or the Dock (on macOS 26 and later its icon follows the light, dark, tinted and clear icon styles), and the Finder opens .flp projects with it. Without --install the app is only written to target/bundled/.

cargo run -p bundle-app -- --install

Plugins: cargo run -p os-app --release installs Lemon Studio's plugins as bundles, signed ad hoc so that Apple silicon loads them, in ~/Library/Audio/Plug-Ins/VST3 and .../CLAP. To build and install them without starting Lemon Studio, run cargo run -p bundle-plugins -- --install.

Notes

Plugin windows dock inside the main window as on Windows, or detach (from their window menu) into windows of their own that stay above Lemon Studio while it is the active application. A few things differ from Windows and Linux:

• Menu bar: the window's menus (FILE … HELP) are also in the macOS menu bar, with the same entries.
• Keys: Command stands in for Ctrl in every shortcut (Command+S saves), and Control+click is a right click. Quit (Command+Q, the menu bar, the Dock) asks about unsaved changes like closing the window does.
• Plugin windows: a minimized detached window is hidden rather than sent to the Dock; its channel's button brings it back. A sample dragged from Lemon Studio's browser onto a plugin window reaches Lemon Sampler only (other plugins take dropped files only from the Finder).
• Microphone: the first time a mixer track monitors or records an input (the Mac's microphone, an audio interface's inputs), macOS asks whether Lemon Studio may use the microphone; System Settings > Privacy & Security > Microphone changes the answer. Started from a terminal, macOS asks on the terminal's behalf instead.
• FL Studio's factory content (samples that projects name through %FLStudioFactoryData%) is found in the newest /Applications/FL Studio *.app; OPENSTUDIO_FACTORY overrides it.
• Settings, themes and presets live in ~/Library/Application Support/Lemon Studio. OPENSTUDIO_USER_DIR overrides the folder.
• Plugins are found in ~/Library/Audio/Plug-Ins/{CLAP,VST3,VST}, /Library/Audio/Plug-Ins/{CLAP,VST3,VST} and CLAP_PATH, plus any folder added in Settings > Plugins. Audio Units are not supported. On Apple silicon, plugins built for Intel Macs only (common among older VST2 plugins) cannot be loaded; VST2 ones are listed as not supported, without being tried.

Using Lemon Studio

Open a project directly by passing its path:

cargo run -p os-app --release -- path/to/project.flp

Use FILE > Export audio (Ctrl+R) to render the song, or the current pattern in PAT mode, to WAV, FLAC, MP3 or OGG files. The same render runs without a window, hosting the same plugins the app would and without opening an audio device:

cargo run -p os-app --release -- --render path/to/project.flp out.wav [--rate 48000] [--seconds 30] [--from TICK] [--builtin-only]

--builtin-only hosts only Lemon Studio's own plugins, for a render that is the same on every machine. Settings > Theme picks the skin (Lemon, or Citrus, the look formerly called Classic) and the theme; the choice is remembered.

Lemon Trio and Lemon Parametric EQ were called Lemon 3x Osc and Lemon Parametric EQ 2 before, and earlier all three plugins were called Open Sampler, Open 3x Osc and Open Parametric EQ 2. They keep their plugin IDs, so sessions saved with the old names still open with the new plugins. Installing the plugins (by the run from source or bundle-plugins --install) removes bundles installed under the old names; delete any others you copied yourself, or DAWs will list each plugin twice.

Tests

cargo test --workspace

Tests that need an audio device are marked #[ignore] and run with cargo test -p os-app -- --ignored. Project-file corpus tests run when OPENSTUDIO_FLP_CORPUS points to a text file listing .flp paths; project files are never committed to this repository. The watermark test (cargo test -p watermark) checks that every source file opens with its header: a copyright line for each of its copyright holders, its SPDX licence identifier and the project's name.

Every test binary is compiled and linked on its own, so a crate keeps its integration tests in one: tests/integration/main.rs names each file there as a module (run one with cargo test -p os-engine --test integration fx_null); a new file goes there, not beside it. The crates have no doc tests (doctest = false: code in doc comments is text or ignore), and a crate without tests has test = false; take that out when adding its first test.

Scripting and assistants

--control <socket> lets scripts, tests and AI assistants read and change the open project over a local socket (JSON-RPC 2.0), and --serve <socket> [project.flp] does the same without a window. Each change is an undo step named after the client; clients can be limited to reading or to proposing changes the user accepts. The protocol and its commands are in docs/control-plane.md.

cargo run -p os-app --release -- --control /tmp/lemon.sock path/to/project.flp

Command-line tools

Architecture

Lemon Studio is a Cargo workspace of focused crates:

Roadmap

The roadmap is kept on the Lemon Studio Discord server, where every item is marked as complete, in progress or not started. The broad next steps are the engine rework (sampler voice, automation), opening projects from older FL Studio versions, more built-in instruments and effects, and the rest of the plugin window features on Linux.

Development approach

Lemon Studio is developed independently. File-format and behaviour details needed for interoperability are first written down as specifications, and the product code is implemented from those specifications and public documentation. All artwork, icons and interface graphics in this repository are original or come from the openly licensed projects listed below.

Contributing

Lemon Studio is not accepting outside contributions yet. Once it does, pull requests will be welcome from developers who are comfortable with Rust and the pull-request workflow.

All contributions must be clean-room work. Decompiled code, and code or pseudocode derived from decompiled output, will not be accepted in any form: the codebase must contain none of it.

Contributors keep the copyright of their work and license it under the GPL, version 3 or later, like the rest of Lemon Studio. In each file you write or substantially change, add a line with your name or username to the copyright lines at the top of the header, Copyright (C) <year> <name>, and keep the lines already there.

Community

Join the Lemon Studio Discord server to follow development and talk about the project. Please keep in mind that support is not offered at this stage.

Third-party components

Their copyright notices and licence texts are collected in THIRD-PARTY-NOTICES.txt, which goes with every copy of Lemon Studio next to LICENSE. Its last section, the Rust crates with their licence texts, is generated by cargo run -p notices (with cargo-about: cargo install cargo-about --locked --features cli); cargo test fails while a crate that goes into a build is missing from it, so run it after changing a dependency.

ASIO is a registered trademark of Steinberg Media Technologies GmbH.

License

Copyright (C) 2026 ItsAlphaNeon and the Lemon Studio contributors. Each source file names its copyright holders in its header.

Lemon Studio is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License, version 3 or (at your option) any later version. It is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

The third-party components listed above keep their authors' copyright and licences, whose notices are in THIRD-PARTY-NOTICES.txt. The two source files that hold others' work (crates/os-vst2/src/abi.rs, crates/os-ui/src/tabler.rs) name it in their header.

A request, not a licence term. As the author, I'd ask that Lemon Studio's code not be used in ArtCraft. This is only a request: it is not part of Lemon Studio's licence, adds no condition to the GPL, and takes away none of the rights the GPL gives you.

Trademarks

FL Studio is a trademark of Image-Line Software. Lemon Studio is an independent project and is not affiliated with, sponsored by or endorsed by Image-Line Software. FL Studio and its .flp file format are referred to solely to describe interoperability.

VST is a registered trademark of Steinberg Media Technologies GmbH. All other trademarks are the property of their respective owners.

_{Copyright © 2026 ItsAlphaNeon and the Lemon Studio contributors. Free software under the GNU GPL, version 3 or later.}