diff --git a/pkgs/development/python-modules/signedjson/default.nix b/pkgs/development/python-modules/signedjson/default.nix
new file mode 100644
index 00000000000..33a615fefd4
--- /dev/null
+++ b/pkgs/development/python-modules/signedjson/default.nix
@@ -0,0 +1,26 @@
+{ stdenv
+, buildPythonPackage
+, fetchgit
+, canonicaljson
+, unpaddedbase64
+, pynacl
+}:
+
+buildPythonPackage rec {
+  pname = "signedjson";
+  version = "1.0.0";
+
+  src = fetchgit {
+    url = "https://github.com/matrix-org/python-signedjson.git";
+    rev = "refs/tags/v${version}";
+    sha256 = "0b8xxhc3npd4567kqapfp4gs7m0h057xam3an7424az262ind82n";
+  };
+
+  propagatedBuildInputs = [ canonicaljson unpaddedbase64 pynacl ];
+
+  meta = with stdenv.lib; {
+    homepage = https://pypi.org/project/signedjson/;
+    description = "Sign JSON with Ed25519 signatures";
+    license = licenses.asl20;
+  };
+}
diff --git a/pkgs/top-level/python-packages.nix b/pkgs/top-level/python-packages.nix
index b561881cf49..92735dbc927 100644
--- a/pkgs/top-level/python-packages.nix
+++ b/pkgs/top-level/python-packages.nix
@@ -4385,20 +4385,7 @@ in {
 
   service-identity = callPackage ../development/python-modules/service_identity { };
 
-  signedjson = buildPythonPackage rec {
-    name = "signedjson-${version}";
-    version = "1.0.0";
-
-    src = pkgs.fetchgit {
-      url = "https://github.com/matrix-org/python-signedjson.git";
-      rev = "refs/tags/v${version}";
-      sha256 = "0b8xxhc3npd4567kqapfp4gs7m0h057xam3an7424az262ind82n";
-    };
-
-    propagatedBuildInputs = with self; [
-      canonicaljson unpaddedbase64 pynacl
-    ];
-  };
+  signedjson = callPackage ../development/python-modules/signedjson { };
 
   unpaddedbase64 = buildPythonPackage rec {
     name = "unpaddedbase64-${version}";