diff --git a/default.nix b/default.nix
new file mode 100644
index 0000000..ff5c5d1
--- /dev/null
+++ b/default.nix
@@ -0,0 +1,17 @@
+let
+  pkgs = import <nixpkgs> { };
+  stdenv = pkgs.stdenv;
+in {
+  shell = pkgs.mkShell {
+    name = "fun-for-fun";
+    args = [ "build" ];
+    src = [ ./lib ./dune-project ];
+    system = builtins.currentSystem;
+    buildInputs = with pkgs; [ opam cmake ];
+    # fixme: I failed to install package by package manager outside nix, maybe it's bad practice. 
+    # shellHooks = ''
+    #   opam install . --deps-only --with-test --yes
+    #   opam install merlin --yes
+    # '';
+  };
+}
diff --git a/shell.nix b/shell.nix
new file mode 100644
index 0000000..1bdf221
--- /dev/null
+++ b/shell.nix
@@ -0,0 +1,2 @@
+
+(import ./default.nix).shell