diff --git a/lass/5pkgs/weechat-matrix/default.nix b/lass/5pkgs/weechat-matrix/default.nix
new file mode 100644
index 000000000..40848caaa
--- /dev/null
+++ b/lass/5pkgs/weechat-matrix/default.nix
@@ -0,0 +1,80 @@
+{ python3Packages
+, lib
+, fetchFromGitHub
+}:
+
+with python3Packages;
+
+let
+  scriptPython = python.withPackages (ps: with ps; [
+    aiohttp
+    requests
+    python_magic
+  ]);
+
+  version = "lassulus-fork";
+in python3Packages.buildPythonPackage {
+  pname = "weechat-matrix";
+  inherit version;
+
+  src = fetchFromGitHub {
+    owner = "poljar";
+    repo = "weechat-matrix";
+    rev = version;
+    hash = "sha256-o4kgneszVLENG167nWnk2FxM+PsMzi+PSyMUMIktZcc=";
+  };
+  # src = ./weechat-matrix;
+
+  propagatedBuildInputs = [
+    pyopenssl
+    webcolors
+    future
+    atomicwrites
+    attrs
+    Logbook
+    pygments
+    matrix-nio
+    aiohttp
+    requests
+  ];
+
+  passthru.scripts = [ "matrix.py" ];
+
+  dontBuild = true;
+  doCheck = false;
+
+  format = "other";
+
+  installPhase = ''
+    mkdir -p $out/share $out/bin
+    cp main.py $out/share/matrix.py
+
+    cp contrib/matrix_upload.py $out/bin/matrix_upload
+    cp contrib/matrix_decrypt.py $out/bin/matrix_decrypt
+    cp contrib/matrix_sso_helper.py $out/bin/matrix_sso_helper
+    substituteInPlace $out/bin/matrix_upload \
+      --replace '/usr/bin/env -S python3' '${scriptPython}/bin/python'
+    substituteInPlace $out/bin/matrix_sso_helper \
+      --replace '/usr/bin/env -S python3' '${scriptPython}/bin/python'
+    substituteInPlace $out/bin/matrix_decrypt \
+      --replace '/usr/bin/env python3' '${scriptPython}/bin/python'
+
+    mkdir -p $out/${python.sitePackages}
+    cp -r matrix $out/${python.sitePackages}/matrix
+  '';
+
+  dontPatchShebangs = true;
+  postFixup = ''
+    addToSearchPath program_PYTHONPATH $out/${python.sitePackages}
+    patchPythonScript $out/share/matrix.py
+    substituteInPlace $out/${python.sitePackages}/matrix/server.py --replace \"matrix_sso_helper\" \"$out/bin/matrix_sso_helper\"
+  '';
+
+  meta = with lib; {
+    description = "A Python plugin for Weechat that lets Weechat communicate over the Matrix protocol";
+    homepage = "https://github.com/poljar/weechat-matrix";
+    license = licenses.isc;
+    platforms = platforms.unix;
+    maintainers = with maintainers; [ tilpner emily ];
+  };
+}