diff --git a/pkgs/applications/audio/soundux/default.nix b/pkgs/applications/audio/soundux/default.nix
new file mode 100644
index 000000000000..f6616e58353e
--- /dev/null
+++ b/pkgs/applications/audio/soundux/default.nix
@@ -0,0 +1,142 @@
+{ lib
+, stdenv
+, fetchFromGitHub
+, cmake
+, pkg-config
+, makeBinaryWrapper
+, pipewire
+, libpulseaudio
+, libappindicator
+, libstartup_notification
+, openssl
+, libwnck
+, pcre
+, util-linux
+, libselinux
+, libsepol
+, libthai
+, libdatrie
+, xorg
+, libxkbcommon
+, libepoxy
+, dbus
+, at-spi2-core
+, nlohmann_json
+, fancypp
+, httplib
+, semver-cpp
+, webkitgtk
+, yt-dlp
+, ffmpeg
+, lsb-release
+}:
+
+stdenv.mkDerivation rec {
+  pname = "soundux";
+  version = "0.2.7";
+
+  src = fetchFromGitHub {
+    owner = "Soundux";
+    repo = "Soundux";
+    rev = version;
+    sha256 = "sha256-aSCsg6nJt6F+6O7UeXnvYva0vllTfsxK/cjaeOhObZY=";
+    fetchSubmodules = true;
+  };
+
+  nativeBuildInputs = [
+    cmake
+    pkg-config
+    makeBinaryWrapper
+  ];
+
+  buildInputs = [
+    pipewire
+    libpulseaudio
+    libappindicator
+    openssl
+    libwnck
+    pcre
+    util-linux
+    libselinux
+    libsepol
+    libthai
+    libdatrie
+    xorg.libXdmcp
+    xorg.libXtst
+    xorg.libXres
+    libxkbcommon
+    libepoxy
+    dbus
+    at-spi2-core
+    nlohmann_json
+    fancypp
+    httplib
+    semver-cpp
+    libstartup_notification
+    webkitgtk
+    yt-dlp
+    ffmpeg
+  ];
+
+  postPatch = ''
+    # cannot be overwritten with variables
+    substituteInPlace CMakeLists.txt \
+      --replace "set(CMAKE_INSTALL_PREFIX \"/opt/soundux\" CACHE PATH \"Install path prefix, prepended onto install directories.\" FORCE)" "" \
+      --replace "/usr/share" "$out/usr/share"
+    substituteInPlace src/ui/impl/webview/webview.cpp \
+      --replace "/usr/share/pixmaps/soundux.png" "$out/share/pixmaps/soundux.png"
+  '';
+
+  # We need to append /opt to our CMAKE_INSTALL_PREFIX
+  dontAddPrefix = true;
+
+  preConfigure = ''
+    # This needs to be set in preConfigure to access the $prefix variable
+    export cmakeFlags="-DCMAKE_INSTALL_PREFIX=$prefix/opt $cmakeFlags"
+
+    # Replace some fetched submodules with symlinks nix packages.
+    rm -rf \
+      lib/json \
+      lib/fancypp \
+      lib/lib-httplib \
+      lib/semver
+
+    ln -s ${nlohmann_json} lib/json
+    ln -s ${fancypp} lib/fancypp
+    ln -s ${httplib} lib/lib-httplib
+    ln -s ${semver-cpp} lib/semver
+  '';
+
+  # Somehow some of the install destination paths in the build system still
+  # gets transformed to point to /var/empty/share, even though they are at least
+  # relative to the nix output directory with our earlier patching.
+  postInstall = ''
+    mv "$out/var/empty/share" "$out"
+    rm -rf "$out/var"
+    mkdir "$out/bin"
+    ln -s "$out/opt/soundux" "$out/bin"
+    substituteInPlace "$out/share/applications/soundux.desktop" \
+      --replace "/opt/soundux/soundux" "soundux"
+  '';
+
+  postFixup = let
+    rpaths = lib.makeLibraryPath [libwnck pipewire libpulseaudio];
+  in ''
+    # Wnck, PipeWire, and PulseAudio are dlopen-ed by Soundux, so they do
+    # not end up on the RPATH during the build process.
+    patchelf --add-rpath "${rpaths}" "$out/opt/soundux-${version}"
+
+    # Work around upstream bug https://github.com/Soundux/Soundux/issues/435
+    wrapProgram "$out/bin/soundux" \
+      --set WEBKIT_DISABLE_COMPOSITING_MODE 1 \
+      --prefix PATH : ${lib.makeBinPath [ yt-dlp ffmpeg lsb-release ]} \
+  '';
+
+  meta = with lib; {
+    description = "A cross-platform soundboard.";
+    homepage = "https://soundux.rocks/";
+    license = licenses.gpl3Plus;
+    platforms = platforms.linux;
+    maintainers = with maintainers; [ aidalgol ];
+  };
+}
diff --git a/pkgs/development/libraries/fancypp/default.nix b/pkgs/development/libraries/fancypp/default.nix
new file mode 100644
index 000000000000..f93ab77c63de
--- /dev/null
+++ b/pkgs/development/libraries/fancypp/default.nix
@@ -0,0 +1,31 @@
+{ lib
+, stdenvNoCC
+, fetchFromGitHub
+}:
+
+stdenvNoCC.mkDerivation rec {
+  pname = "fancypp";
+  version = "unstable-2021-04-08";
+
+  src = fetchFromGitHub {
+    owner = "Curve";
+    repo = "fancypp";
+    rev = "ede7f712a08f7c66ff4a5590ad94a477c48850a5";
+    sha256 = "sha256-E2JsQnvrqrZFYo+xBJr7xDCoPnRQftqUjjBpZzFvIic=";
+  };
+
+  # Header-only library.
+  dontBuild = true;
+
+  installPhase = ''
+    mkdir "$out"
+    cp -r include "$out"
+  '';
+
+  meta = with lib; {
+    description = "Tiny C++ Library for terminal colors and more!";
+    homepage = "https://github.com/Curve/fancypp";
+    maintainers = with maintainers; [ aidalgol ];
+    license = licenses.mit;
+  };
+}
diff --git a/pkgs/development/libraries/httplib/default.nix b/pkgs/development/libraries/httplib/default.nix
new file mode 100644
index 000000000000..19618613ee17
--- /dev/null
+++ b/pkgs/development/libraries/httplib/default.nix
@@ -0,0 +1,31 @@
+{ lib
+, stdenvNoCC
+, fetchFromGitHub
+}:
+
+stdenvNoCC.mkDerivation rec {
+  pname = "httplib";
+  version = "0.11.1";
+
+  src = fetchFromGitHub {
+    owner = "yhirose";
+    repo = "cpp-httplib";
+    rev = "v${version}";
+    sha256 = "sha256-rsElqtoRz/sOXpAsfSJbMlwIKdaGJkSZfKHzB/wMhY8=";
+  };
+
+  # Header-only library.
+  dontBuild = true;
+
+  installPhase = ''
+    mkdir -p "$out/include"
+    cp -r httplib.h "$out/include"
+  '';
+
+  meta = with lib; {
+    description = "A C++ header-only HTTP/HTTPS server and client library";
+    homepage = "https://github.com/yhirose/cpp-httplib";
+    maintainers = with maintainers; [ aidalgol ];
+    license = licenses.mit;
+  };
+}
diff --git a/pkgs/development/libraries/semver-cpp/default.nix b/pkgs/development/libraries/semver-cpp/default.nix
new file mode 100644
index 000000000000..966f170eaad0
--- /dev/null
+++ b/pkgs/development/libraries/semver-cpp/default.nix
@@ -0,0 +1,31 @@
+{ lib
+, stdenvNoCC
+, fetchFromGitHub
+}:
+
+stdenvNoCC.mkDerivation rec {
+  pname = "semver-cpp";
+  version = "0.3.0";
+
+  src = fetchFromGitHub {
+    owner = "Neargye";
+    repo = "semver";
+    rev = "v${version}";
+    sha256 = "sha256-nRWmY/GJtSkPJIW7i7/eIr/YtfyvYhJVZBRIDXUC7xg=";
+  };
+
+  # Header-only library.
+  dontBuild = true;
+
+  installPhase = ''
+    mkdir "$out"
+    cp -r include "$out"
+  '';
+
+  meta = with lib; {
+    description = "Semantic Versioning for modern C++";
+    homepage = "https://github.com/Neargye/semver";
+    maintainers = with maintainers; [ aidalgol ];
+    license = licenses.mit;
+  };
+}
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 5c5ff93076cc..2f1f4c79fb94 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -18944,6 +18944,8 @@ with pkgs;
   factor-lang-scope = callPackage ../development/compilers/factor-lang/scope.nix { };
   factor-lang = factor-lang-scope.interpreter;
 
+  fancypp = callPackage ../development/libraries/fancypp { };
+
   far2l = callPackage ../applications/misc/far2l {
     stdenv = if stdenv.cc.isClang then llvmPackages.stdenv else stdenv;
     inherit (darwin.apple_sdk.frameworks) IOKit Carbon Cocoa AudioToolbox OpenGL;
@@ -19248,6 +19250,8 @@ with pkgs;
 
   graphinder = callPackage ../tools/security/graphinder { };
 
+  httplib = callPackage ../development/libraries/httplib { };
+
   icon-lang = callPackage ../development/interpreters/icon-lang { };
 
   libgit2 = callPackage ../development/libraries/libgit2 {
@@ -22470,6 +22474,8 @@ with pkgs;
 
   seasocks = callPackage ../development/libraries/seasocks { };
 
+  semver-cpp = callPackage ../development/libraries/semver-cpp { };
+
   serd = callPackage ../development/libraries/serd {};
 
   serf = callPackage ../development/libraries/serf {
@@ -24216,6 +24222,10 @@ with pkgs;
     boost = boost172;
   };
 
+  soundux = callPackage ../applications/audio/soundux {
+    yt-dlp = yt-dlp.override { withAlias = true; };
+  };
+
   tomcat_connectors = callPackage ../servers/http/apache-modules/tomcat-connectors { };
 
   tomcat-native = callPackage ../servers/http/tomcat/tomcat-native.nix { };