diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4ae4987a..6d3cfa5d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -95,6 +95,7 @@ add_subdirectory(xo-pydistribution)
 add_subdirectory(xo-simulator)
 add_subdirectory(xo-pysimulator)
 add_subdirectory(xo-process)
+add_subdirectory(xo-pyprocess)
 #
 add_subdirectory(xo-expression)
 add_subdirectory(xo-pyexpression)
@@ -103,6 +104,5 @@ add_subdirectory(xo-reader)
 add_subdirectory(xo-jit)
 add_subdirectory(xo-pyjit)
 #
-#add_subdirectory(xo-pyprocess)
 #add_subdirectory(xo-kalmanfilter)
 #add_subdirectory(xo-pykalmanfilter)
diff --git a/default.nix b/default.nix
index 106bf973..412f3c74 100644
--- a/default.nix
+++ b/default.nix
@@ -68,6 +68,7 @@ let
           xo-simulator      = self.callPackage pkgs/xo-simulator.nix      {};
           xo-pysimulator    = self.callPackage pkgs/xo-pysimulator.nix    {};
           xo-process        = self.callPackage pkgs/xo-process.nix        {};
+          xo-pyprocess      = self.callPackage pkgs/xo-pyprocess.nix      {};
 #
           xo-expression     = self.callPackage pkgs/xo-expression.nix     {};
           xo-pyexpression   = self.callPackage pkgs/xo-pyexpression.nix   {};
@@ -80,7 +81,6 @@ let
           xo-pyjit          = self.callPackage pkgs/xo-pyjit.nix          {};
 
 #          xo-pysimulator    = self.callPackage pkgs/xo-pysimulator.nix    {};
-#          xo-pyprocess      = self.callPackage pkgs/xo-pyprocess.nix      {};
 #          xo-kalmanfilter   = self.callPackage pkgs/xo-kalmanfilter.nix   {};
 #          xo-pykalmanfilter = self.callPackage pkgs/xo-pykalmanfilter.nix {};
 #
diff --git a/pkgs/xo-pyprocess.nix b/pkgs/xo-pyprocess.nix
new file mode 100644
index 00000000..5401b408
--- /dev/null
+++ b/pkgs/xo-pyprocess.nix
@@ -0,0 +1,33 @@
+{
+  # nixpkgs dependencies
+  stdenv, cmake, catch2,
+
+  python3Packages,
+
+  # xo dependencies
+  xo-cmake,
+  #xo-refcnt,
+  xo-process,
+
+  xo-pyreactor,
+  xo-pywebutil,
+} :
+
+stdenv.mkDerivation (finalattrs:
+  {
+    name = "xo-pyprocess";
+
+    src = ../xo-pyprocess;
+
+    cmakeFlags = ["-DCMAKE_MODULE_PATH=${xo-cmake}/share/cmake"];
+    #doCheck = true;
+    nativeBuildInputs = [ cmake catch2 xo-cmake ];
+    propagatedBuildInputs = [
+#      xo-printjson
+      xo-pyreactor
+      xo-pywebutil
+      xo-process
+#      python3Packages.python
+      python3Packages.pybind11
+    ];
+  })
diff --git a/pkgs/xo-userenv.nix b/pkgs/xo-userenv.nix
index 3b18646d..20425306 100644
--- a/pkgs/xo-userenv.nix
+++ b/pkgs/xo-userenv.nix
@@ -53,7 +53,7 @@
   xo-simulator,
   xo-pysimulator,
   xo-process,
-  #xo-pyprocess,
+  xo-pyprocess,
   #xo-kalmanfilter,
   #  xo-pykalmanfilter,
 #
@@ -101,6 +101,7 @@ buildEnv {
             xo-simulator
             xo-pysimulator
             xo-process
+            xo-pyprocess
 #
             xo-expression
             xo-pyexpression
@@ -108,7 +109,6 @@ buildEnv {
             xo-reader
             xo-jit
             xo-pyjit
-#            xo-pyprocess
 #            xo-kalmanfilter
 #            xo-pykalmanfilter
           ];