diff --git a/flake.nix b/flake.nix
index 825d4f5b6..fdb766cf4 100644
--- a/flake.nix
+++ b/flake.nix
@@ -386,15 +386,7 @@
                 { rpc-server = deltachat-rpc-server-win32; arch = "win32"; binaryName = "deltachat-rpc-server.exe"; };
 
             # Run `nix build .#docs` to get C docs generated in `./result/`.
-            docs =
-              pkgs.stdenv.mkDerivation {
-                pname = "docs";
-                version = manifest.version;
-                src = pkgs.lib.cleanSource ./.;
-                nativeBuildInputs = [ pkgs.doxygen ];
-                buildPhase = ''scripts/run-doxygen.sh'';
-                installPhase = ''mkdir -p $out; cp -av deltachat-ffi/html deltachat-ffi/xml $out'';
-              };
+            docs = pkgs.callPackage ./nix/c-docs.nix { version = manifest.version; };
 
             libdeltachat =
               let
diff --git a/nix/c-docs.nix b/nix/c-docs.nix
new file mode 100644
index 000000000..0b74f03d6
--- /dev/null
+++ b/nix/c-docs.nix
@@ -0,0 +1,9 @@
+{ pkgs, version }:
+pkgs.stdenv.mkDerivation {
+  pname = "docs";
+  inherit version;
+  src = pkgs.lib.cleanSource ../.;
+  nativeBuildInputs = [ pkgs.doxygen ];
+  buildPhase = ''scripts/run-doxygen.sh'';
+  installPhase = ''mkdir -p $out; cp -av deltachat-ffi/html deltachat-ffi/xml $out'';
+}