diff --git a/packages/default.nix b/packages/default.nix
index 7d74a3f..df635ee 100644
--- a/packages/default.nix
+++ b/packages/default.nix
@@ -1,5 +1,34 @@
-{pkgs, ...}:
-with pkgs; {
-  gh-get = callPackage ./gh-get {};
-  groovy-language-server = callPackage ./groovy-language-server {};
-}
+{pkgs, ...}: let
+  baresip = import ./studio-link-baresip;
+in
+  with pkgs; rec {
+    gh-get = callPackage ./gh-get {};
+    groovy-language-server = callPackage ./groovy-language-server {};
+    opus = callPackage ./opus {};
+    overlay-onair-lv2 = callPackage ./overlay-onair-lv2 {
+      inherit opus;
+      baresip = studio-link-baresip-effectonair-plugin;
+      libre = studio-link-libre;
+    };
+    overlay-vst = callPackage ./overlay-vst {
+      inherit vst-sdk opus;
+      baresip = studio-link-baresip-effect-plugin;
+      libre = studio-link-libre;
+    };
+    studio-link-baresip-effect-plugin =
+      callPackage baresip.effect-plugin
+      {
+        inherit opus;
+        libre = studio-link-libre;
+        librem = studio-link-librem;
+      };
+    studio-link-baresip-effectonair-plugin = callPackage baresip.effectonair-plugin {
+      inherit opus;
+      libre = studio-link-libre;
+      librem = studio-link-librem;
+    };
+    studio-link-libre = callPackage ./studio-link-libre {};
+    studio-link-librem = callPackage ./studio-link-librem {libre = studio-link-libre;};
+    ultraschall-soundboard = callPackage ./ultraschall-soundboard {};
+    vst-sdk = callPackage ./vst-sdk {};
+  }
diff --git a/packages/opus/default.nix b/packages/opus/default.nix
new file mode 100644
index 0000000..084bbcf
--- /dev/null
+++ b/packages/opus/default.nix
@@ -0,0 +1,27 @@
+{
+  lib,
+  stdenv,
+  fetchzip,
+}:
+stdenv.mkDerivation (finalAttrs: {
+  pname = "opus";
+  version = "1.3.1";
+
+  # https://github.com/Studio-Link/3rdparty/blob/v21.04.0/dist/build.sh#L147
+  src = fetchzip {
+    url = "https://archive.mozilla.org/pub/opus/opus-${finalAttrs.version}.tar.gz";
+    sha256 = "sha256-VyHmKoRXCJ0shVfUn6cX13b0fAXIQk0Z5NLZIfy8Gh4=";
+  };
+
+  configureFlags = [
+    # https://github.com/Studio-Link/3rdparty/blob/v21.04.0/dist/build.sh#L163
+    "--with-pic"
+    # required to output libopus.a used in overlay-onair-lv2
+    "--enable-static"
+  ];
+
+  makeFlags =
+    ["PREFIX=$(out)"]
+    ++ lib.optional (stdenv.cc.cc != null) "SYSROOT_ALT=${stdenv.cc.cc}"
+    ++ lib.optional (stdenv.cc.libc != null) "SYSROOT=${lib.getDev stdenv.cc.libc}";
+})
diff --git a/packages/overlay-onair-lv2/default.nix b/packages/overlay-onair-lv2/default.nix
new file mode 100644
index 0000000..4686e1d
--- /dev/null
+++ b/packages/overlay-onair-lv2/default.nix
@@ -0,0 +1,49 @@
+{
+  baresip,
+  libre,
+  libxcrypt,
+  lv2,
+  opus,
+  openssl,
+  zlib,
+  stdenv,
+  fetchFromGitHub,
+}:
+stdenv.mkDerivation {
+  pname = "studio-link-onair-plugin";
+  version = "latest";
+  src = fetchFromGitHub {
+    owner = "Studio-Link";
+    repo = "overlay-onair-lv2";
+    rev = "d58f3035208672f3a6f3e21bb6d0232c06cbab2d";
+    sha256 = "sha256-bU1WdAqj7ZRTfwZPoajEtIeqUF0cM6IF4ektaCL6vew=";
+  };
+
+  postPatch = ''
+    substituteInPlace build.sh \
+      --replace "../my_include/libbaresip_onair.a" "${baresip}/lib/libbaresip.a" \
+      --replace "../re/libre.a" "${libre}/lib/libre.a" \
+      --replace "../rem/librem.a" "" \
+      --replace "../3rdparty/lib/libopus.a" "${opus}/lib/libopus.a"
+  '';
+
+  buildInputs = [
+    baresip
+    libre
+    libxcrypt
+    lv2
+    openssl
+    zlib
+  ];
+
+  buildPhase = ''
+    patchShebangs --build build.sh
+    ./build.sh
+  '';
+
+  installPhase = ''
+    mkdir -p $out/lib
+    cp studio-link-onair.so $out/lib/
+    cp *.ttl $out/lib/
+  '';
+}
diff --git a/packages/overlay-vst/default.nix b/packages/overlay-vst/default.nix
new file mode 100644
index 0000000..b4e28cd
--- /dev/null
+++ b/packages/overlay-vst/default.nix
@@ -0,0 +1,41 @@
+{
+  baresip,
+  libre,
+  stdenv,
+  fetchFromGitHub,
+  vst-sdk,
+  openssl,
+  opus,
+}:
+stdenv.mkDerivation {
+  pname = "studio-link-plugin";
+  version = "latest";
+  src = fetchFromGitHub {
+    owner = "Studio-Link";
+    repo = "overlay-vst";
+    rev = "8efd287cb86ee601fda8054456da038f1128808a";
+    sha256 = "sha256-xP99uqdr4LmCQEydiVX3SHVYizHo+2pmjOLNVz62kGg=";
+  };
+
+  postPatch = ''
+    rm Makefile
+    mv Makefile.linux Makefile
+    substituteInPlace Makefile \
+      --replace "vstsdk2.4" "${vst-sdk}/include" \
+      --replace "../baresip/libbaresip.a" "${baresip}/lib/libbaresip.a" \
+      --replace "../re/libre.a" "${libre}/lib/libre.a" \
+      --replace "../rem/librem.a" ""
+  '';
+
+  buildInputs = [
+    baresip
+    libre
+    openssl
+    opus
+  ];
+
+  installPhase = ''
+    mkdir -p $out/lib
+    cp studio-link.so $out/lib/
+  '';
+}
diff --git a/packages/studio-link-baresip/default.nix b/packages/studio-link-baresip/default.nix
new file mode 100644
index 0000000..98e084a
--- /dev/null
+++ b/packages/studio-link-baresip/default.nix
@@ -0,0 +1,156 @@
+rec {
+  flavor = {modules}: {
+    lib,
+    stdenv,
+    fetchzip,
+    fetchFromGitHub,
+    zlib,
+    openssl,
+    libre,
+    librem,
+    pkg-config,
+    gst_all_1,
+    cairo,
+    mpg123,
+    alsa-lib,
+    SDL2,
+    libv4l,
+    celt,
+    libsndfile,
+    srtp,
+    ffmpeg,
+    gsm,
+    speex,
+    portaudio,
+    spandsp3,
+    libuuid,
+    libvpx,
+    opus,
+    flac,
+  }: let
+    studio-link-app = fetchFromGitHub {
+      owner = "Studio-Link";
+      repo = "app";
+      rev = "v21.07.0-stable";
+      sha256 = "sha256-BjMZQDweQMM2TZuYoAGWE9eC/Vy8UnwDkkieY9TKpyg=";
+    };
+    # See https://github.com/Studio-Link/app/blob/v21.07.0-stable/dist/lib/functions.sh#L37-L43
+    studio-link-webui = fetchzip {
+      url = "https://download.studio.link/devel/v21.xx.x/v21.12.0-beta-3bb3eaf/webui.zip";
+      sha256 = "sha256-7SkMQ8WM7vgFuiKS8+BFat4M/a9VNrWQKLMynKE4sEU=";
+    };
+  in
+    stdenv.mkDerivation (finalAttrs: {
+      pname = "baresip-studio-link";
+      version = "1.0.0";
+      src = fetchzip {
+        url = "https://github.com/baresip/baresip/archive/v${finalAttrs.version}.tar.gz";
+        sha256 = "sha256-HCnLidhuLP1QzFJ93jTk/+N86S+qZKnvtFHUAyUXPRM=";
+      };
+
+      # Link custom modules, see https://github.com/Studio-Link/app/blob/v21.07.0-stable/dist/lib/functions.sh#L123-L131
+      postUnpack = ''
+        rm -rf $sourceRoot/modules/g722
+        ln -s ${studio-link-app}/src/modules/g722 $sourceRoot/modules/g722
+        ln -s ${studio-link-app}/src/modules/slogging $sourceRoot/modules/slogging
+        ln -s ${studio-link-app}/src/modules/effect $sourceRoot/modules/effect
+        ln -s ${studio-link-app}/src/modules/effectonair $sourceRoot/modules/effectonair
+        ln -s ${studio-link-app}/src/modules/apponair $sourceRoot/modules/apponair
+        ln -s ${studio-link-app}/src/modules/slaudio $sourceRoot/modules/slaudio
+
+        mkdir -p $sourceRoot/modules/webapp/assets
+        cp -r ${studio-link-app}/src/modules/webapp/* $sourceRoot/modules/webapp/
+        cp ${studio-link-webui}/headers/* $sourceRoot/modules/webapp/assets/
+      '';
+
+      # Patches are defined here: https://github.com/Studio-Link/app/blob/v21.07.0-stable/dist/lib/functions.sh#L110-L115
+      patches = [
+        "${studio-link-app}/dist/patches/config.patch"
+        "${studio-link-app}/dist/patches/fix_check_telev_and_pthread.patch"
+        "${studio-link-app}/dist/patches/dtls_aes256.patch"
+        "${studio-link-app}/dist/patches/rtcp_mux_softphone.patch"
+        "${studio-link-app}/dist/patches/fallback_dns.patch"
+        "${studio-link-app}/dist/patches/baresip_audio_rtp_discard.patch"
+      ];
+
+      nativeBuildInputs = [pkg-config];
+
+      buildInputs =
+        [
+          zlib
+          openssl
+          libre
+          librem
+          cairo
+          mpg123
+          alsa-lib
+          SDL2
+          libv4l
+          celt
+          libsndfile
+          srtp
+          ffmpeg
+          gsm
+          speex
+          portaudio
+          spandsp3
+          libuuid
+          libvpx
+          opus
+          flac
+        ]
+        ++ (with gst_all_1; [gstreamer gst-libav gst-plugins-base gst-plugins-bad gst-plugins-good]);
+
+      # https://github.com/Studio-Link/app/blob/v21.07.0-stable/dist/build.sh#L123C18-L123C97
+      preBuild = ''
+        makeFlagsArray+=(MODULES="opus stdio ice g711 turn stun uuid auloop g722 slogging dtls_srtp ${modules}")
+      '';
+
+      makeFlags =
+        [
+          "LIBRE_MK=${libre}/share/re/re.mk"
+          "LIBRE_INC=${libre}/include/re"
+          "LIBRE_SO=${libre}/lib"
+          "LIBREM_PATH=${librem}"
+          "PREFIX=$(out)"
+          "USE_VIDEO=1"
+          "CCACHE_DISABLE=1"
+
+          # https://github.com/Studio-Link/app/blob/v21.07.0-stable/dist/build.sh#L122
+          "STATIC=1"
+          # https://github.com/Studio-Link/app/blob/v21.07.0-stable/dist/build.sh#L125
+          "libbaresip.a"
+        ]
+        ++ lib.optional (stdenv.cc.cc != null) "SYSROOT_ALT=${stdenv.cc.cc}"
+        ++ lib.optional (stdenv.cc.libc != null) "SYSROOT=${stdenv.cc.libc}";
+
+      # -DSLPLUGIN coming from https://github.com/Studio-Link/app/blob/v21.07.0-stable/dist/build.sh#L124C40-L124C50
+      # Include of webapp coming from https://github.com/Studio-Link/app/blob/v21.07.0-stable/dist/lib/functions.sh#L136
+      NIX_CFLAGS_COMPILE = ''
+        -I${librem}/include/rem
+        -I${gsm}/include/gsm
+        -I${studio-link-app}/src/modules/webapp
+        -DHAVE_INTTYPES_H
+        -D__GLIBC__
+        -D__need_timeval
+        -D__need_timespec
+        -D__need_time_t
+        -DSLPLUGIN
+      '';
+
+      postInstall = ''
+        mkdir -p $out/include
+        cp include/* $out/include/
+
+        mkdir -p $out/lib
+        cp libbaresip.a $out/lib
+      '';
+    });
+
+  effect-plugin = flavor {
+    modules = "webapp effect";
+  };
+  effectonair-plugin = flavor {
+    modules = "apponair effectonair";
+  };
+}
diff --git a/packages/studio-link-libre/default.nix b/packages/studio-link-libre/default.nix
new file mode 100644
index 0000000..e88f058
--- /dev/null
+++ b/packages/studio-link-libre/default.nix
@@ -0,0 +1,40 @@
+{
+  lib,
+  stdenv,
+  fetchzip,
+  fetchpatch,
+  openssl,
+  zlib,
+}:
+stdenv.mkDerivation (finalAttrs: {
+  pname = "studio-link-libre";
+  version = "1.1.0";
+  src = fetchzip {
+    url = "https://github.com/baresip/re/archive/v${finalAttrs.version}.tar.gz";
+    sha256 = "sha256-LZ45aS9uVN8j2jkmVkDv406iDYqtpuXni8H1bCCrmVw=";
+  };
+
+  # see https://github.com/Studio-Link/app/blob/v21.07.0-stable/dist/lib/functions.sh#L80-L83
+  patches = [
+    (fetchpatch {
+      url = "https://raw.githubusercontent.com/Studio-Link/app/v21.07.0-stable/dist/patches/bluetooth_conflict.patch";
+      sha256 = "sha256-QuMst4avD18UeZJi5v0XI0Um8JMMR6f2/tNXD8IXrCA=";
+    })
+    (fetchpatch {
+      url = "https://raw.githubusercontent.com/Studio-Link/app/v21.07.0-stable/dist/patches/re_fix_authorization.patch";
+      sha256 = "sha256-rZxsaRFnH0JSxiRIjHPmNx5q8rqRMKeXT8Grnua9hrU=";
+    })
+    (fetchpatch {
+      url = "https://raw.githubusercontent.com/Studio-Link/app/v21.07.0-stable/dist/patches/re_pull_66.diff";
+      sha256 = "sha256-ksgmb00F4jfIG/qFEtiEK4nuENGUcAP9D22zPipMWmE=";
+    })
+  ];
+
+  patchFlags = ["--ignore-whitespace" "-p1"];
+
+  buildInputs = [zlib openssl];
+  makeFlags =
+    ["USE_ZLIB=1" "USE_OPENSSL=1" "PREFIX=$(out)"]
+    ++ lib.optional (stdenv.cc.cc != null) "SYSROOT_ALT=${stdenv.cc.cc}"
+    ++ lib.optional (stdenv.cc.libc != null) "SYSROOT=${lib.getDev stdenv.cc.libc}";
+})
diff --git a/packages/studio-link-librem/default.nix b/packages/studio-link-librem/default.nix
new file mode 100644
index 0000000..63062fa
--- /dev/null
+++ b/packages/studio-link-librem/default.nix
@@ -0,0 +1,25 @@
+{
+  lib,
+  stdenv,
+  fetchurl,
+  zlib,
+  openssl,
+  libre,
+}:
+stdenv.mkDerivation (finalAttrs: {
+  version = "0.6.0";
+  pname = "studio-link-librem";
+  src = fetchurl {
+    url = "https://github.com/creytiv/rem/archive/v${finalAttrs.version}.tar.gz";
+    sha256 = "0b17wma5w9acizk02isk5k83vv47vf1cf9zkmsc1ail677d20xj1";
+  };
+  buildInputs = [zlib openssl libre];
+  makeFlags =
+    [
+      "LIBRE_MK=${libre}/share/re/re.mk"
+      "LIBRE_INC=${libre}/include/re"
+      "PREFIX=$(out)"
+    ]
+    ++ lib.optional (stdenv.cc.cc != null) "SYSROOT_ALT=${lib.getDev stdenv.cc.cc}"
+    ++ lib.optional (stdenv.cc.libc != null) "SYSROOT=${lib.getDev stdenv.cc.libc}";
+})
diff --git a/packages/ultraschall-soundboard/default.nix b/packages/ultraschall-soundboard/default.nix
new file mode 100644
index 0000000..4c1f3c4
--- /dev/null
+++ b/packages/ultraschall-soundboard/default.nix
@@ -0,0 +1,58 @@
+{
+  lib,
+  stdenv,
+  fetchFromGitHub,
+  cmake,
+  pkg-config,
+  alsa-lib,
+  freetype,
+  juce,
+  libX11,
+  libXcursor,
+  libXext,
+  libXinerama,
+  libXrandr,
+}:
+stdenv.mkDerivation (finalAttrs: {
+  pname = "ultraschall-soundboard";
+  version = "8a7a538831d8dbf7689b47611d218560762ae869";
+
+  src = fetchFromGitHub {
+    owner = "Ultraschall";
+    repo = "ultraschall-soundboard";
+    rev = "${finalAttrs.version}";
+    sha256 = "sha256-ddvfUI08h8cKJ2Hoac0unEsQryjPhZGnWpIm/pg0jUk=";
+  };
+
+  nativeBuildInputs = [
+    cmake
+    pkg-config
+  ];
+
+  buildInputs = [
+    alsa-lib
+    freetype
+    juce
+    libX11
+    libXcursor
+    libXext
+    libXinerama
+    libXrandr
+  ];
+  # configureFlags = [
+  #   "-Bbuild"
+  #   "-GNinja"
+  #   "-Wno-dev"
+  #   "-DCMAKE_BUILD_TYPE=Release"
+  # ];
+
+  # cmakeFlags = [
+  #   "--build"
+  #   "build"
+  #   "--target"
+  #   "UltraschallSoundboard_VST3"
+  #   "--config"
+  #   "Release"
+  #   "-j"
+  # ];
+})
diff --git a/packages/vst-sdk/default.nix b/packages/vst-sdk/default.nix
new file mode 100644
index 0000000..882b7a2
--- /dev/null
+++ b/packages/vst-sdk/default.nix
@@ -0,0 +1,31 @@
+{
+  stdenvNoCC,
+  fetchzip,
+  fetchpatch,
+}:
+stdenvNoCC.mkDerivation {
+  pname = "vst-sdk";
+  version = "2.4";
+  src = fetchzip {
+    url = "https://download.studio.link/tools/vstsdk367_03_03_2017_build_352.zip";
+    sha256 = "sha256-9HUbAlQc815SEck98xinXexJhpUi+/CXUkAUqCOJhM0=";
+  };
+
+  postUnpack = ''
+    mv $sourceRoot/VST2_SDK $sourceRoot/vstsdk2.4
+  '';
+
+  patches = [
+    (fetchpatch {
+      url = "https://raw.githubusercontent.com/Studio-Link/overlay-vst/master/vst2_linux.patch";
+      sha256 = "sha256-l9QGYDUiQUaFmGTAfNvMZsZLZ70/aSU6wz8ACsRJPQM=";
+    })
+  ];
+
+  patchFlags = ["-p0"];
+
+  installPhase = ''
+    mkdir -p $out/include
+    cp -r vstsdk2.4/* $out/include/
+  '';
+}