diff --git a/machines/web02/cas-eleves/default.nix b/machines/web02/cas-eleves/default.nix
index ad8bdcc..61f42fb 100644
--- a/machines/web02/cas-eleves/default.nix
+++ b/machines/web02/cas-eleves/default.nix
@@ -11,7 +11,21 @@ let
 
   port = 9889;
 
-  python3 = pkgs.python312;
+  python3 = pkgs.python312.override {
+    packageOverrides = _: _: {
+      inherit
+        (import sources.nix-pkgs {
+          inherit pkgs;
+          python3 = pkgs.python312;
+        })
+        django-browser-reload
+        django-bulma-forms
+        django-cas-server
+        loadcredential
+        ;
+    };
+  };
+
   pythonEnv = python3.withPackages (ps: [
     ps.django
     ps.ldap3
@@ -19,10 +33,10 @@ let
     ps.psycopg
 
     # Local packages
-    (ps.callPackage ./packages/django-browser-reload { })
-    (ps.callPackage ./packages/django-bulma-forms { })
-    (ps.callPackage ./packages/django-cas-server { })
-    (ps.callPackage ./packages/loadcredential { })
+    ps.django-browser-reload
+    ps.django-bulma-forms
+    ps.django-cas-server
+    ps.loadcredential
   ]);
 
   staticDrv = pkgs.stdenv.mkDerivation {
diff --git a/machines/web02/cas-eleves/packages/django-browser-reload/default.nix b/machines/web02/cas-eleves/packages/django-browser-reload/default.nix
deleted file mode 100644
index 96d243f..0000000
--- a/machines/web02/cas-eleves/packages/django-browser-reload/default.nix
+++ /dev/null
@@ -1,42 +0,0 @@
-{
-  lib,
-  buildPythonPackage,
-  fetchFromGitHub,
-  setuptools,
-  wheel,
-  asgiref,
-  django,
-}:
-
-buildPythonPackage rec {
-  pname = "django-browser-reload";
-  version = "1.12.1";
-  pyproject = true;
-
-  src = fetchFromGitHub {
-    owner = "adamchainz";
-    repo = "django-browser-reload";
-    rev = version;
-    hash = "sha256-IDIkAl6YYI3isDvpzCtAu4fLSr2gbjEvVW+K1WBDPbo=";
-  };
-
-  nativeBuildInputs = [
-    setuptools
-    wheel
-  ];
-
-  propagatedBuildInputs = [
-    asgiref
-    django
-  ];
-
-  pythonImportsCheck = [ "django_browser_reload" ];
-
-  meta = with lib; {
-    description = "Automatically reload your browser in development";
-    homepage = "https://github.com/adamchainz/django-browser-reload";
-    changelog = "https://github.com/adamchainz/django-browser-reload/blob/${src.rev}/CHANGELOG.rst";
-    license = licenses.mit;
-    maintainers = [ ]; # with maintainers; [ thubrecht ];
-  };
-}
diff --git a/machines/web02/cas-eleves/packages/django-bulma-forms/default.nix b/machines/web02/cas-eleves/packages/django-bulma-forms/default.nix
deleted file mode 100644
index 58403f3..0000000
--- a/machines/web02/cas-eleves/packages/django-bulma-forms/default.nix
+++ /dev/null
@@ -1,36 +0,0 @@
-{
-  lib,
-  buildPythonPackage,
-  fetchgit,
-  setuptools,
-  setuptools-scm,
-  wheel,
-  django,
-}:
-
-buildPythonPackage rec {
-  pname = "django-bulma-forms";
-  version = "0.1.4";
-  pyproject = true;
-
-  src = fetchgit {
-    url = "https://git.hubrecht.ovh/hubrecht/django-bulma-forms";
-    rev = "v${version}";
-    hash = "sha256-4KTMXx3YxDxB4/YH14pJnNYtpOGXeDmD+gcbrUHwD/w=";
-  };
-
-  nativeBuildInputs = [
-    setuptools
-    setuptools-scm
-    wheel
-  ];
-
-  propagatedBuildInputs = [ django ];
-
-  meta = with lib; {
-    description = "";
-    homepage = "https://git.hubrecht.ovh/hubrecht/django-bulma-forms";
-    license = licenses.eupl12;
-    maintainers = [ ]; # with maintainers; [ thubrecht ];
-  };
-}
diff --git a/machines/web02/cas-eleves/packages/django-cas-server/01-pytest.patch b/machines/web02/cas-eleves/packages/django-cas-server/01-pytest.patch
deleted file mode 100644
index caf18ad..0000000
--- a/machines/web02/cas-eleves/packages/django-cas-server/01-pytest.patch
+++ /dev/null
@@ -1,88 +0,0 @@
-diff --git a/cas_server/tests/test_federate.py b/cas_server/tests/test_federate.py
-index 2b389d3..dcdfafd 100644
---- a/cas_server/tests/test_federate.py
-+++ b/cas_server/tests/test_federate.py
-@@ -16,6 +16,7 @@ from cas_server.default_settings import settings
- import django
- from django.test import TestCase, Client
- from django.test.utils import override_settings
-+import pytest
- 
- from six.moves import reload_module
- 
-@@ -64,6 +65,7 @@ class FederateAuthLoginLogoutTestCase(
-             ) in response.content.decode("utf-8"))
-         self.assertEqual(response.context['post_url'], '/federate')
- 
-+    @pytest.mark.skip(reason="Address already in use")
-     def test_login_post_provider(self, remember=False):
-         """test a successful login wrokflow"""
-         tickets = []
-@@ -159,6 +161,7 @@ class FederateAuthLoginLogoutTestCase(
-             self.assertTrue(response["Location"].startswith("%s?ticket=" % self.service))
-         return tickets
- 
-+    @pytest.mark.skip(reason="Address already in use")
-     def test_login_twice(self):
-         """Test that user id db is used for the second login (cf coverage)"""
-         self.test_login_post_provider()
-@@ -253,6 +256,7 @@ class FederateAuthLoginLogoutTestCase(
-         self.assertEqual(response.status_code, 200)
-         self.assertIn(b"Invalid response from your identity provider CAS", response.content)
- 
-+    @pytest.mark.skip(reason="Address already in use")
-     def test_auth_federate_slo(self):
-         """test that SLO receive from backend CAS log out the users"""
-         # get tickets and connected clients
-@@ -301,6 +305,7 @@ class FederateAuthLoginLogoutTestCase(
-                     client, response, username=provider.build_username(settings.CAS_TEST_USER)
-                 )
- 
-+    @pytest.mark.skip(reason="Address already in use")
-     def test_federate_logout(self):
-         """
-             test the logout function: the user should be log out
-@@ -340,6 +345,7 @@ class FederateAuthLoginLogoutTestCase(
-                 response = client.get("/login")
-                 self.assert_login_failed(client, response)
- 
-+    @pytest.mark.skip(reason="Address already in use")
-     def test_remember_provider(self):
-         """
-             If the user check remember, next login should not offer the chose of the backend CAS
-@@ -355,6 +361,7 @@ class FederateAuthLoginLogoutTestCase(
-                 provider.suffix
-             ))
- 
-+    @pytest.mark.skip(reason="Address already in use")
-     def test_forget_provider(self):
-         """Test the logout option to forget remembered provider"""
-         tickets = self.test_login_post_provider(remember=True)
-@@ -365,6 +372,7 @@ class FederateAuthLoginLogoutTestCase(
-             client.get("/logout?forget_provider=1")
-             self.assertEqual(client.cookies["remember_provider"]["max-age"], 0)
- 
-+    @pytest.mark.skip(reason="Address already in use")
-     def test_renew(self):
-         """
-             Test authentication renewal with federation mode
-diff --git a/cas_server/tests/test_utils.py b/cas_server/tests/test_utils.py
-index d690724..73ee761 100644
---- a/cas_server/tests/test_utils.py
-+++ b/cas_server/tests/test_utils.py
-@@ -17,6 +17,7 @@ from django.db import connection
- import six
- import warnings
- import datetime
-+import pytest
- 
- from cas_server import utils
- 
-@@ -61,6 +62,7 @@ class CheckPasswordCase(TestCase):
-             )
-         )
- 
-+    @pytest.mark.skip(reason="crypt is broken somehow")
-     def test_crypt(self):
-         """test the crypt auth method"""
-         salts = ["$6$UVVAQvrMyXMF3FF3", "aa"]
diff --git a/machines/web02/cas-eleves/packages/django-cas-server/default.nix b/machines/web02/cas-eleves/packages/django-cas-server/default.nix
deleted file mode 100644
index 3b9bbd4..0000000
--- a/machines/web02/cas-eleves/packages/django-cas-server/default.nix
+++ /dev/null
@@ -1,64 +0,0 @@
-{
-  lib,
-  buildPythonPackage,
-  pytestCheckHook,
-  fetchFromGitHub,
-  setuptools,
-  wheel,
-  django,
-  lxml,
-  requests,
-  requests-futures,
-  six,
-  pytest-django,
-  pytest-env,
-  pytest-runner,
-  mock,
-}:
-
-buildPythonPackage rec {
-  pname = "django-cas-server";
-  version = "unstable-2024-04-13";
-  format = "pyproject";
-
-  src = fetchFromGitHub {
-    owner = "nitmir";
-    repo = "django-cas-server";
-    rev = "a04477d34eedba4fcc91f00a22689defd3f22a7f";
-    hash = "sha256-K6SKnYBiA1TrSdDSodYJoz1Bk20PsNo2g0dvs4XdmY0=";
-  };
-
-  patches = [ ./01-pytest.patch ];
-
-  nativeBuildInputs = [
-    setuptools
-    wheel
-  ];
-
-  propagatedBuildInputs = [
-    django
-    lxml
-    requests
-    requests-futures
-    setuptools
-    six
-  ];
-
-  nativeCheckInputs = [
-    mock
-    pytestCheckHook
-    pytest-django
-    pytest-env
-    pytest-runner
-  ];
-
-  pythonImportsCheck = [ "cas_server" ];
-
-  meta = with lib; {
-    description = "A Django Central Authentication Service server implementing the CAS Protocol 3.0 Specification";
-    homepage = "https://github.com/nitmir/django-cas-server";
-    changelog = "https://github.com/nitmir/django-cas-server/blob/${src.rev}/CHANGELOG.rst";
-    license = licenses.gpl3Only;
-    maintainers = [ ];
-  };
-}
diff --git a/machines/web02/cas-eleves/packages/loadcredential/default.nix b/machines/web02/cas-eleves/packages/loadcredential/default.nix
deleted file mode 100644
index 114fb52..0000000
--- a/machines/web02/cas-eleves/packages/loadcredential/default.nix
+++ /dev/null
@@ -1,34 +0,0 @@
-{
-  lib,
-  buildPythonPackage,
-  fetchFromGitHub,
-  setuptools,
-  wheel,
-}:
-
-buildPythonPackage rec {
-  pname = "loadcredential";
-  version = "1.1";
-  pyproject = true;
-
-  src = fetchFromGitHub {
-    owner = "Tom-Hubrecht";
-    repo = "loadcredential";
-    rev = "v${version}";
-    hash = "sha256-GXpMqGLDmDnTGa9cBYe0CP3Evm5sQ3AK9u6k3mLAW34=";
-  };
-
-  build-system = [
-    setuptools
-    wheel
-  ];
-
-  pythonImportsCheck = [ "loadcredential" ];
-
-  meta = {
-    description = "A simple python package to read credentials passed through systemd's LoadCredential, with a fallback on env variables ";
-    homepage = "https://github.com/Tom-Hubrecht/loadcredential";
-    license = lib.licenses.mit;
-    maintainers = [ ]; # with lib.maintainers; [ thubrecht ];
-  };
-}
diff --git a/npins/sources.json b/npins/sources.json
index f385dad..a139716 100644
--- a/npins/sources.json
+++ b/npins/sources.json
@@ -175,6 +175,17 @@
       "url": null,
       "hash": "1c6cc44pwlg3ky6cnwhkml8ci77fw3sgjhwvqg0f6igxxf2fqv9v"
     },
+    "nix-pkgs": {
+      "type": "Git",
+      "repository": {
+        "type": "Git",
+        "url": "https://git.hubrecht.ovh/hubrecht/nix-pkgs"
+      },
+      "branch": "main",
+      "revision": "1a0f0ad29565db768db52d92973f92993c7c16ed",
+      "url": null,
+      "hash": "14yiyh6zg3kybnqh1dfmwcm7hydc1xvapsamf4hzbnfssfgzvvwk"
+    },
     "nixos-23.11": {
       "type": "Channel",
       "name": "nixos-23.11",