diff --git a/.gitignore b/.gitignore
index 4e82d27..bb80336 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,40 +1,42 @@
-# Autosave files
-*~
-
-# build
-[Oo]bj/
-[Bb]in/
-packages/
-TestResults/
-
-# globs
-Makefile.in
-*.DS_Store
-*.sln.cache
-*.suo
-*.cache
-*.pidb
-*.userprefs
-*.usertasks
-config.log
-config.make
-config.status
-aclocal.m4
-install-sh
-autom4te.cache/
-*.user
-*.tar.gz
-tarballs/
-test-results/
-Thumbs.db
-
-# Mac bundle stuff
-*.dmg
-*.app
-
-# resharper
-*_Resharper.*
-*.Resharper
-
-# dotCover
-*.dotCover
+# Autosave files
+*~
+
+# build
+[Oo]bj/
+[Bb]in/
+packages/
+TestResults/
+
+# globs
+Makefile.in
+*.DS_Store
+*.sln.cache
+*.suo
+*.cache
+*.pidb
+*.userprefs
+*.usertasks
+config.log
+config.make
+config.status
+aclocal.m4
+install-sh
+autom4te.cache/
+*.user
+*.tar.gz
+tarballs/
+test-results/
+Thumbs.db
+
+# Mac bundle stuff
+*.dmg
+*.app
+
+# resharper
+*_Resharper.*
+*.Resharper
+
+# dotCover
+*.dotCover
+
+result
\ No newline at end of file
diff --git a/0001-patch-csproj-to-find-the-openxml-dll.patch b/0001-patch-csproj-to-find-the-openxml-dll.patch
new file mode 100644
index 0000000..444624a
--- /dev/null
+++ b/0001-patch-csproj-to-find-the-openxml-dll.patch
@@ -0,0 +1,52 @@
+From 8c764df6ad27d08b207029879f63d59838c6b53d Mon Sep 17 00:00:00 2001
+From: Jappie Klooster <jappieklooster@hotmail.com>
+Date: Mon, 25 Jul 2022 13:36:18 +0200
+Subject: [PATCH] patch csproj to find the openxml dll
+
+---
+ XlsxValidator.csproj | 8 ++++----
+ 1 file changed, 4 insertions(+), 4 deletions(-)
+
+diff --git a/XlsxValidator.csproj b/XlsxValidator.csproj
+index 06bba76..272b4b5 100644
+--- a/XlsxValidator.csproj
++++ b/XlsxValidator.csproj
+@@ -53,7 +53,7 @@
+     <When Condition="$(TargetFrameworkIdentifier) == '.NETFramework' And $(TargetFrameworkVersion) == 'v3.5'">
+       <ItemGroup>
+         <Reference Include="DocumentFormat.OpenXml">
+-          <HintPath>..\packages\DocumentFormat.OpenXml\lib\net35\DocumentFormat.OpenXml.dll</HintPath>
++          <HintPath>lib\dotnet\DocumentFormat.OpenXml\net35\DocumentFormat.OpenXml.dll</HintPath>
+           <Private>True</Private>
+           <Paket>True</Paket>
+         </Reference>
+@@ -62,7 +62,7 @@
+     <When Condition="$(TargetFrameworkIdentifier) == '.NETFramework' And ($(TargetFrameworkVersion) == 'v4.0' Or $(TargetFrameworkVersion) == 'v4.5' Or $(TargetFrameworkVersion) == 'v4.5.1' Or $(TargetFrameworkVersion) == 'v4.5.2' Or $(TargetFrameworkVersion) == 'v4.5.3')">
+       <ItemGroup>
+         <Reference Include="DocumentFormat.OpenXml">
+-          <HintPath>..\packages\DocumentFormat.OpenXml\lib\net40\DocumentFormat.OpenXml.dll</HintPath>
++          <HintPath>lib\dotnet\DocumentFormat.OpenXml\net40\DocumentFormat.OpenXml.dll</HintPath>
+           <Private>True</Private>
+           <Paket>True</Paket>
+         </Reference>
+@@ -71,7 +71,7 @@
+     <When Condition="$(TargetFrameworkIdentifier) == '.NETFramework' And ($(TargetFrameworkVersion) == 'v4.6' Or $(TargetFrameworkVersion) == 'v4.6.1' Or $(TargetFrameworkVersion) == 'v4.6.2' Or $(TargetFrameworkVersion) == 'v4.6.3')">
+       <ItemGroup>
+         <Reference Include="DocumentFormat.OpenXml">
+-          <HintPath>..\packages\DocumentFormat.OpenXml\lib\net46\DocumentFormat.OpenXml.dll</HintPath>
++          <HintPath>lib\dotnet\DocumentFormat.OpenXml\net46\DocumentFormat.OpenXml.dll</HintPath>
+           <Private>True</Private>
+           <Paket>True</Paket>
+         </Reference>
+@@ -80,7 +80,7 @@
+     <When Condition="($(TargetFrameworkIdentifier) == '.NETStandard' And ($(TargetFrameworkVersion) == 'v1.3' Or $(TargetFrameworkVersion) == 'v1.4' Or $(TargetFrameworkVersion) == 'v1.5' Or $(TargetFrameworkVersion) == 'v1.6')) Or ($(TargetFrameworkIdentifier) == '.NETCoreApp' And $(TargetFrameworkVersion) == 'v1.0')">
+       <ItemGroup>
+         <Reference Include="DocumentFormat.OpenXml">
+-          <HintPath>..\packages\DocumentFormat.OpenXml\lib\netstandard1.3\DocumentFormat.OpenXml.dll</HintPath>
++          <HintPath>lib\dotnet\DocumentFormat.OpenXml\netstandard1.3\DocumentFormat.OpenXml.dll</HintPath>
+           <Private>True</Private>
+           <Paket>True</Paket>
+         </Reference>
+-- 
+2.33.3
+
diff --git a/default.nix b/default.nix
new file mode 100644
index 0000000..c92c165
--- /dev/null
+++ b/default.nix
@@ -0,0 +1,45 @@
+/*
+some_program/default.nix
+nix-build -E 'with import <nixpkgs> { }; callPackage ./default.nix { }'
+*/
+
+{ lib
+, stdenv
+, fetchFromGitHub
+, fetchNuGet
+, buildDotnetPackage
+, dotnetPackages
+, pkg-config
+, callPackage
+}:
+let
+  openxml = callPackage ./nix/openxml.nix {};
+in
+# https://github.com/NixOS/nixpkgs/blob/master/pkgs/build-support/dotnet/build-dotnet-package/default.nix
+buildDotnetPackage rec {
+  pname = "xlsx-validator";
+  baseName = pname; # workaround for "called without baseName"
+  version = "1.0";
+  src = ./XlsxValidator;
+  projectFile = ["./XlsxValidator.csproj"];
+
+  patches = [ ./0001-patch-csproj-to-find-the-openxml-dll.patch];
+
+
+  # we patch in the openxml ref by hand,
+  # nix doesn't appear to do depencencies yet
+  preBuild = ''
+   set -xe
+   cp -r ${openxml}/lib ./lib
+   ls
+   ls ./lib/dotnet/DocumentFormat.OpenXml
+  '';
+  nativeBuildInputs = [
+    pkg-config
+  ];
+  meta = {
+    homepage = "some_homepage";
+    description = "some_description";
+    license = lib.licenses.mit;
+  };
+}
diff --git a/nix/build.nix b/nix/build.nix
new file mode 100644
index 0000000..e578e72
--- /dev/null
+++ b/nix/build.nix
@@ -0,0 +1,6 @@
+# convenience insta build script
+let
+  pkgs = import ./pin.nix {};
+in
+pkgs.callPackage ../default.nix {}
+# pkgs.callPackage ./openxml.nix {}
diff --git a/nix/openxml.nix b/nix/openxml.nix
new file mode 100644
index 0000000..1f0efcb
--- /dev/null
+++ b/nix/openxml.nix
@@ -0,0 +1,13 @@
+/*
+get's openxml
+*/
+{ fetchNuGet,
+}:
+
+# https://www.nuget.org/packages/DocumentFormat.OpenXml
+fetchNuGet {
+    pname = "DocumentFormat.OpenXml";
+    version = "2.17.1";
+    sha256 = "05fcyh53hz6m45pgq49lvgaz9a150hkgl66xx6i4inaax9kcpr46";
+    outputFiles = [ "lib/*" ];
+    }
diff --git a/nix/pin.nix b/nix/pin.nix
new file mode 100644
index 0000000..7a28f2d
--- /dev/null
+++ b/nix/pin.nix
@@ -0,0 +1,6 @@
+import (builtins.fetchGit {
+    # Descriptive name to make the store path easier to identify
+    name = "nixos-pin-2022.05.07";
+    url = "https://github.com/nixos/nixpkgs/";
+    rev = "18854d7bbc472919eace2303779d1653a78bd63b";
+    })
diff --git a/shell.nix b/shell.nix
new file mode 100644
index 0000000..827b24f
--- /dev/null
+++ b/shell.nix
@@ -0,0 +1,6 @@
+let
+  pkgs = import ./nix/pin.nix {};
+in
+pkgs.mkShell {
+  buildInputs = [pkgs.dotnet-sdk];
+}