diff --git a/pkgs/development/python-modules/adblock/default.nix b/pkgs/development/python-modules/adblock/default.nix
index 075c73e566cb..325032dac931 100644
--- a/pkgs/development/python-modules/adblock/default.nix
+++ b/pkgs/development/python-modules/adblock/default.nix
@@ -60,7 +60,7 @@ buildPythonPackage rec {
     libiconv
   ];
 
-  PSL_PATH = "${publicsuffix-list}/share/publicsuffix/public_suffix_list.dat";
+  env.PSL_PATH = "${publicsuffix-list}/share/publicsuffix/public_suffix_list.dat";
 
   nativeCheckInputs = [
     pytestCheckHook
diff --git a/pkgs/development/python-modules/atproto/default.nix b/pkgs/development/python-modules/atproto/default.nix
index 8d6ffc08b509..055acdf93f84 100644
--- a/pkgs/development/python-modules/atproto/default.nix
+++ b/pkgs/development/python-modules/atproto/default.nix
@@ -36,7 +36,7 @@ buildPythonPackage rec {
     hash = "sha256-0NogKxYO+lCtNhK2ZWwRLQTV7rHU5Oz+lnE4awsoPsM=";
   };
 
-  POETRY_DYNAMIC_VERSIONING_BYPASS = version;
+  env.POETRY_DYNAMIC_VERSIONING_BYPASS = version;
 
   build-system = [
     poetry-core
diff --git a/pkgs/development/python-modules/banks/default.nix b/pkgs/development/python-modules/banks/default.nix
index 9798a2f50f93..2bb4a2189891 100644
--- a/pkgs/development/python-modules/banks/default.nix
+++ b/pkgs/development/python-modules/banks/default.nix
@@ -29,7 +29,7 @@ buildPythonPackage (finalAttrs: {
     hash = "sha256-wa3refEIYQIPmtl8NGtoyg2PTY3zQt6R4EgXUbcUgrk=";
   };
 
-  SSL_CERT_FILE = "${cacert}/etc/ssl/certs/ca-bundle.crt";
+  env.SSL_CERT_FILE = "${cacert}/etc/ssl/certs/ca-bundle.crt";
 
   build-system = [ hatchling ];
 
diff --git a/pkgs/development/python-modules/bimmer-connected/default.nix b/pkgs/development/python-modules/bimmer-connected/default.nix
index 7ffc85411b0a..bb1e96e45099 100644
--- a/pkgs/development/python-modules/bimmer-connected/default.nix
+++ b/pkgs/development/python-modules/bimmer-connected/default.nix
@@ -33,7 +33,7 @@ buildPythonPackage rec {
     setuptools
   ];
 
-  PBR_VERSION = version;
+  env.PBR_VERSION = version;
 
   dependencies = [
     httpx
diff --git a/pkgs/development/python-modules/carbon/default.nix b/pkgs/development/python-modules/carbon/default.nix
index 7ea88b54262f..86efd5ce79ff 100644
--- a/pkgs/development/python-modules/carbon/default.nix
+++ b/pkgs/development/python-modules/carbon/default.nix
@@ -29,7 +29,7 @@ buildPythonPackage rec {
 
   # Carbon-s default installation is /opt/graphite. This env variable ensures
   # carbon is installed as a regular Python module.
-  GRAPHITE_NO_PREFIX = "True";
+  env.GRAPHITE_NO_PREFIX = "True";
 
   postPatch = ''
     substituteInPlace setup.py \
diff --git a/pkgs/development/python-modules/cassandra-driver/default.nix b/pkgs/development/python-modules/cassandra-driver/default.nix
index bd577244aadf..d4a86bc566a7 100644
--- a/pkgs/development/python-modules/cassandra-driver/default.nix
+++ b/pkgs/development/python-modules/cassandra-driver/default.nix
@@ -66,7 +66,7 @@ buildPythonPackage rec {
   ++ lib.concatAttrValues optional-dependencies;
 
   # This is used to determine the version of cython that can be used
-  CASS_DRIVER_ALLOWED_CYTHON_VERSION = cython.version;
+  env.CASS_DRIVER_ALLOWED_CYTHON_VERSION = cython.version;
 
   preBuild = ''
     export CASS_DRIVER_BUILD_CONCURRENCY=$NIX_BUILD_CORES
diff --git a/pkgs/development/python-modules/cppe/default.nix b/pkgs/development/python-modules/cppe/default.nix
index 63c05e7998a7..5bbaffa08e05 100644
--- a/pkgs/development/python-modules/cppe/default.nix
+++ b/pkgs/development/python-modules/cppe/default.nix
@@ -42,7 +42,9 @@ buildPythonPackage {
 
   buildInputs = [ pybind11 ] ++ lib.optional stdenv.cc.isClang llvmPackages.openmp;
 
-  NIX_CFLAGS_LINK = lib.optional stdenv.cc.isClang "-lomp";
+  env = lib.optionalAttrs stdenv.cc.isClang {
+    NIX_CFLAGS_LINK = "-lomp";
+  };
 
   hardeningDisable = lib.optional stdenv.cc.isClang "strictoverflow";
 
diff --git a/pkgs/development/python-modules/django-annoying/default.nix b/pkgs/development/python-modules/django-annoying/default.nix
index 5ececfb35041..efc39512ad25 100644
--- a/pkgs/development/python-modules/django-annoying/default.nix
+++ b/pkgs/development/python-modules/django-annoying/default.nix
@@ -28,7 +28,7 @@ buildPythonPackage (finalAttrs: {
     six
   ];
 
-  DJANGO_SETTINGS_MODULE = "tests.settings";
+  env.DJANGO_SETTINGS_MODULE = "tests.settings";
 
   nativeCheckInputs = [
     pytest-django
diff --git a/pkgs/development/python-modules/django-cacheops/default.nix b/pkgs/development/python-modules/django-cacheops/default.nix
index c6a046b2cd32..f0c7d41d02a5 100644
--- a/pkgs/development/python-modules/django-cacheops/default.nix
+++ b/pkgs/development/python-modules/django-cacheops/default.nix
@@ -54,7 +54,7 @@ buildPythonPackage rec {
     redisTestHook
   ];
 
-  DJANGO_SETTINGS_MODULE = "tests.settings";
+  env.DJANGO_SETTINGS_MODULE = "tests.settings";
 
   meta = {
     description = "Slick ORM cache with automatic granular event-driven invalidation for Django";
diff --git a/pkgs/development/python-modules/django-celery-email/default.nix b/pkgs/development/python-modules/django-celery-email/default.nix
index 258db03a52a1..368dce09ba1e 100644
--- a/pkgs/development/python-modules/django-celery-email/default.nix
+++ b/pkgs/development/python-modules/django-celery-email/default.nix
@@ -28,7 +28,7 @@ buildPythonPackage rec {
     celery
   ];
 
-  DJANGO_SETTINGS_MODULE = "tests.settings";
+  env.DJANGO_SETTINGS_MODULE = "tests.settings";
 
   nativeCheckInputs = [
     pytest-django
diff --git a/pkgs/development/python-modules/django-ckeditor/default.nix b/pkgs/development/python-modules/django-ckeditor/default.nix
index 1c05c28ba54d..d33dae8bcff6 100644
--- a/pkgs/development/python-modules/django-ckeditor/default.nix
+++ b/pkgs/development/python-modules/django-ckeditor/default.nix
@@ -31,7 +31,7 @@ buildPythonPackage rec {
     pillow
   ];
 
-  DJANGO_SETTINGS_MODULE = "ckeditor_demo.settings";
+  env.DJANGO_SETTINGS_MODULE = "ckeditor_demo.settings";
 
   checkInputs = [
     django-extensions
diff --git a/pkgs/development/python-modules/django-hierarkey/default.nix b/pkgs/development/python-modules/django-hierarkey/default.nix
index f7bcb1f94938..f366fb3fa58c 100644
--- a/pkgs/development/python-modules/django-hierarkey/default.nix
+++ b/pkgs/development/python-modules/django-hierarkey/default.nix
@@ -39,7 +39,7 @@ buildPythonPackage rec {
     pytestCheckHook
   ];
 
-  DJANGO_SETTINGS_MODULE = "tests.settings";
+  env.DJANGO_SETTINGS_MODULE = "tests.settings";
 
   enabledTestPaths = [ "tests" ];
 
diff --git a/pkgs/development/python-modules/django-sekizai/default.nix b/pkgs/development/python-modules/django-sekizai/default.nix
index 36c9ce04a0ec..f32a2a9f9cc7 100644
--- a/pkgs/development/python-modules/django-sekizai/default.nix
+++ b/pkgs/development/python-modules/django-sekizai/default.nix
@@ -26,7 +26,7 @@ buildPythonPackage rec {
 
   pythonImportsCheck = [ "sekizai" ];
 
-  DJANGO_SETTINGS_MODULE = "tests.settings";
+  env.DJANGO_SETTINGS_MODULE = "tests.settings";
 
   meta = {
     description = "Define placeholders where your blocks get rendered and append to those blocks";
diff --git a/pkgs/development/python-modules/django-tinymce/default.nix b/pkgs/development/python-modules/django-tinymce/default.nix
index 82d7e0b06374..9e66148afb6b 100644
--- a/pkgs/development/python-modules/django-tinymce/default.nix
+++ b/pkgs/development/python-modules/django-tinymce/default.nix
@@ -23,7 +23,7 @@ buildPythonPackage rec {
 
   dependencies = [ django ];
 
-  DJANGO_SETTINGS_MODULE = "tests.settings";
+  env.DJANGO_SETTINGS_MODULE = "tests.settings";
 
   checkInputs = [
     pytest-django
diff --git a/pkgs/development/python-modules/ducc0/default.nix b/pkgs/development/python-modules/ducc0/default.nix
index 7262ba256ab8..61e02af2b93d 100644
--- a/pkgs/development/python-modules/ducc0/default.nix
+++ b/pkgs/development/python-modules/ducc0/default.nix
@@ -30,8 +30,10 @@ buildPythonPackage rec {
     substituteInPlace pyproject.toml --replace-fail '"pybind11>=2.13.6", ' ""
   '';
 
-  DUCC0_USE_NANOBIND = "";
-  DUCC0_OPTIMIZATION = "portable";
+  env = {
+    DUCC0_USE_NANOBIND = "";
+    DUCC0_OPTIMIZATION = "portable";
+  };
 
   build-system = [
     cmake
diff --git a/pkgs/development/python-modules/emailthreads/default.nix b/pkgs/development/python-modules/emailthreads/default.nix
index 21eced43f96c..fdb06f2436cc 100644
--- a/pkgs/development/python-modules/emailthreads/default.nix
+++ b/pkgs/development/python-modules/emailthreads/default.nix
@@ -22,7 +22,7 @@ buildPythonPackage rec {
 
   nativeCheckInputs = [ unittestCheckHook ];
 
-  PKGVER = version;
+  env.PKGVER = version;
 
   meta = {
     homepage = "https://github.com/emersion/python-emailthreads";
diff --git a/pkgs/development/python-modules/flashinfer/default.nix b/pkgs/development/python-modules/flashinfer/default.nix
index 5882d0ee8164..2e1119edc390 100644
--- a/pkgs/development/python-modules/flashinfer/default.nix
+++ b/pkgs/development/python-modules/flashinfer/default.nix
@@ -87,7 +87,7 @@ buildPythonPackage rec {
     export MAX_JOBS="$NIX_BUILD_CORES"
   '';
 
-  FLASHINFER_CUDA_ARCH_LIST = lib.concatStringsSep ";" torch.cudaCapabilities;
+  env.FLASHINFER_CUDA_ARCH_LIST = lib.concatStringsSep ";" torch.cudaCapabilities;
 
   pythonRemoveDeps = [
     "nvidia-cudnn-frontend"
diff --git a/pkgs/development/python-modules/flatbuffers/default.nix b/pkgs/development/python-modules/flatbuffers/default.nix
index db0405cc34d1..3c36197b7f3d 100644
--- a/pkgs/development/python-modules/flatbuffers/default.nix
+++ b/pkgs/development/python-modules/flatbuffers/default.nix
@@ -13,7 +13,7 @@ buildPythonPackage rec {
 
   # flatbuffers needs VERSION environment variable for setting the correct
   # version, otherwise it uses the current date.
-  VERSION = version;
+  env.VERSION = version;
 
   pythonImportsCheck = [ "flatbuffers" ];
 
diff --git a/pkgs/development/python-modules/grpcio/default.nix b/pkgs/development/python-modules/grpcio/default.nix
index 722d3990eafe..a7c59f6a2c4f 100644
--- a/pkgs/development/python-modules/grpcio/default.nix
+++ b/pkgs/development/python-modules/grpcio/default.nix
@@ -64,10 +64,12 @@ buildPythonPackage rec {
     unset AR
   '';
 
-  GRPC_BUILD_WITH_BORING_SSL_ASM = "";
-  GRPC_PYTHON_BUILD_SYSTEM_OPENSSL = 1;
-  GRPC_PYTHON_BUILD_SYSTEM_ZLIB = 1;
-  GRPC_PYTHON_BUILD_SYSTEM_CARES = 1;
+  env = {
+    GRPC_BUILD_WITH_BORING_SSL_ASM = "";
+    GRPC_PYTHON_BUILD_SYSTEM_OPENSSL = 1;
+    GRPC_PYTHON_BUILD_SYSTEM_ZLIB = 1;
+    GRPC_PYTHON_BUILD_SYSTEM_CARES = 1;
+  };
 
   # does not contain any tests
   doCheck = false;
diff --git a/pkgs/development/python-modules/ifcopenshell/default.nix b/pkgs/development/python-modules/ifcopenshell/default.nix
index 37988bb8452e..09a67f05d542 100644
--- a/pkgs/development/python-modules/ifcopenshell/default.nix
+++ b/pkgs/development/python-modules/ifcopenshell/default.nix
@@ -130,7 +130,7 @@ buildPythonPackage rec {
 
   pythonImportsCheck = [ "ifcopenshell" ];
 
-  PYTHONUSERBASE = ".";
+  env.PYTHONUSERBASE = ".";
 
   # We still build with python to generate ifcopenshell_wrapper.py and ifcopenshell_wrapper.so
   cmakeFlags = [
diff --git a/pkgs/development/python-modules/jax/default.nix b/pkgs/development/python-modules/jax/default.nix
index 97876cc1148f..d310e737c433 100644
--- a/pkgs/development/python-modules/jax/default.nix
+++ b/pkgs/development/python-modules/jax/default.nix
@@ -64,7 +64,7 @@ buildPythonPackage rec {
 
   # The version is automatically set to ".dev" if this variable is not set.
   # https://github.com/google/jax/commit/e01f2617b85c5bdffc5ffb60b3d8d8ca9519a1f3
-  JAX_RELEASE = "1";
+  env.JAX_RELEASE = "1";
 
   dependencies = [
     jaxlib
diff --git a/pkgs/development/python-modules/kaldi-active-grammar/default.nix b/pkgs/development/python-modules/kaldi-active-grammar/default.nix
index 192e48ab78f1..38c00df1b2db 100644
--- a/pkgs/development/python-modules/kaldi-active-grammar/default.nix
+++ b/pkgs/development/python-modules/kaldi-active-grammar/default.nix
@@ -34,8 +34,10 @@ buildPythonPackage rec {
     sha256 = "sha256-VyVshIEVp/ep4Ih7Kj66GF02JEZ4nwgJOtgR2DarzdY=";
   };
 
-  KALDI_BRANCH = "foo";
-  KALDIAG_SETUP_RAW = "1";
+  env = {
+    KALDI_BRANCH = "foo";
+    KALDIAG_SETUP_RAW = "1";
+  };
 
   patches = [
     # Makes sure scikit-build doesn't try to build the dependencies for us
diff --git a/pkgs/development/python-modules/mxnet/default.nix b/pkgs/development/python-modules/mxnet/default.nix
index b42ba43501fe..5dcd11a257dd 100644
--- a/pkgs/development/python-modules/mxnet/default.nix
+++ b/pkgs/development/python-modules/mxnet/default.nix
@@ -30,7 +30,7 @@ buildPythonPackage {
     "numpy"
   ];
 
-  LD_LIBRARY_PATH = lib.makeLibraryPath [ pkgs.mxnet ];
+  env.LD_LIBRARY_PATH = toString (lib.makeLibraryPath [ pkgs.mxnet ]);
 
   postPatch = ''
     # Required to support numpy >=1.24 where np.bool is removed in favor of just bool
diff --git a/pkgs/development/python-modules/nbconflux/default.nix b/pkgs/development/python-modules/nbconflux/default.nix
index 660e9f80fee5..9a6eae1e713d 100644
--- a/pkgs/development/python-modules/nbconflux/default.nix
+++ b/pkgs/development/python-modules/nbconflux/default.nix
@@ -47,7 +47,7 @@ buildPythonPackage rec {
     rm versioneer.py
   '';
 
-  JUPYTER_PATH = "${nbconvert}/share/jupyter";
+  env.JUPYTER_PATH = "${nbconvert}/share/jupyter";
   disabledTests = [
     "test_post_to_confluence"
     "test_optional_components"
diff --git a/pkgs/development/python-modules/nbsphinx/default.nix b/pkgs/development/python-modules/nbsphinx/default.nix
index 22501d467876..cb8470681163 100644
--- a/pkgs/development/python-modules/nbsphinx/default.nix
+++ b/pkgs/development/python-modules/nbsphinx/default.nix
@@ -42,7 +42,7 @@ buildPythonPackage rec {
   # The package has not tests
   doCheck = false;
 
-  JUPYTER_PATH = "${nbconvert}/share/jupyter";
+  env.JUPYTER_PATH = "${nbconvert}/share/jupyter";
 
   pythonImportsCheck = [ "nbsphinx" ];
 
diff --git a/pkgs/development/python-modules/oslo-log/default.nix b/pkgs/development/python-modules/oslo-log/default.nix
index c72df54a7976..c221fb175b4c 100644
--- a/pkgs/development/python-modules/oslo-log/default.nix
+++ b/pkgs/development/python-modules/oslo-log/default.nix
@@ -37,7 +37,7 @@ buildPythonPackage rec {
 
   # Manually set version because prb wants to get it from the git upstream repository (and we are
   # installing from tarball instead)
-  PBR_VERSION = version;
+  env.PBR_VERSION = version;
 
   build-system = [ setuptools ];
 
diff --git a/pkgs/development/python-modules/psycopg/default.nix b/pkgs/development/python-modules/psycopg/default.nix
index e3e13ac78944..caa8eb862cc2 100644
--- a/pkgs/development/python-modules/psycopg/default.nix
+++ b/pkgs/development/python-modules/psycopg/default.nix
@@ -134,12 +134,6 @@ buildPythonPackage rec {
 
   sphinxRoot = "../docs";
 
-  # Introduce this file necessary for the docs build via environment var
-  LIBPQ_DOCS_FILE = fetchurl {
-    url = "https://raw.githubusercontent.com/postgres/postgres/496a1dc44bf1261053da9b3f7e430769754298b4/doc/src/sgml/libpq.sgml";
-    hash = "sha256-JwtCngkoi9pb0pqIdNgukY8GbG5pUDZvrGAHZqjFOw4";
-  };
-
   inherit patches;
 
   # only move to sourceRoot after patching, makes patching easier
@@ -185,6 +179,11 @@ buildPythonPackage rec {
   ++ optional-dependencies.pool;
 
   env = {
+    # Introduce this file necessary for the docs build via environment var
+    LIBPQ_DOCS_FILE = fetchurl {
+      url = "https://raw.githubusercontent.com/postgres/postgres/496a1dc44bf1261053da9b3f7e430769754298b4/doc/src/sgml/libpq.sgml";
+      hash = "sha256-JwtCngkoi9pb0pqIdNgukY8GbG5pUDZvrGAHZqjFOw4";
+    };
     postgresqlEnableTCP = 1;
     PGUSER = "psycopg";
     PGDATABASE = "psycopg";
diff --git a/pkgs/development/python-modules/pycrypto/default.nix b/pkgs/development/python-modules/pycrypto/default.nix
index 72000acad17e..c79abd49ec1d 100644
--- a/pkgs/development/python-modules/pycrypto/default.nix
+++ b/pkgs/development/python-modules/pycrypto/default.nix
@@ -9,7 +9,7 @@ buildPythonPackage rec {
   format = "setuptools";
 
   # Cannot build wheel otherwise (zip 1980 issue)
-  SOURCE_DATE_EPOCH = 315532800;
+  env.SOURCE_DATE_EPOCH = 315532800;
 
   # We need to have a dist-info folder, so let's create one with setuptools
   unpackPhase = ''
diff --git a/pkgs/development/python-modules/pyerfa/default.nix b/pkgs/development/python-modules/pyerfa/default.nix
index 0f3da6940a6d..5ed9dab2a770 100644
--- a/pkgs/development/python-modules/pyerfa/default.nix
+++ b/pkgs/development/python-modules/pyerfa/default.nix
@@ -38,7 +38,7 @@ buildPythonPackage rec {
   '';
 
   # See https://github.com/liberfa/pyerfa/issues/112#issuecomment-1721197483
-  NIX_CFLAGS_COMPILE = "-O2";
+  env.NIX_CFLAGS_COMPILE = "-O2";
   nativeCheckInputs = [
     pytestCheckHook
     pytest-doctestplus
diff --git a/pkgs/development/python-modules/pygit2/default.nix b/pkgs/development/python-modules/pygit2/default.nix
index 76673d096c22..0d793e367bf8 100644
--- a/pkgs/development/python-modules/pygit2/default.nix
+++ b/pkgs/development/python-modules/pygit2/default.nix
@@ -50,7 +50,7 @@ buildPythonPackage rec {
 
   # Tests require certificates
   # https://github.com/NixOS/nixpkgs/pull/72544#issuecomment-582674047
-  SSL_CERT_FILE = "${cacert}/etc/ssl/certs/ca-bundle.crt";
+  env.SSL_CERT_FILE = "${cacert}/etc/ssl/certs/ca-bundle.crt";
 
   pythonImportsCheck = [ "pygit2" ];
 
diff --git a/pkgs/development/python-modules/pyhepmc/default.nix b/pkgs/development/python-modules/pyhepmc/default.nix
index 28339c457468..4e34a3bc239c 100644
--- a/pkgs/development/python-modules/pyhepmc/default.nix
+++ b/pkgs/development/python-modules/pyhepmc/default.nix
@@ -38,7 +38,7 @@ buildPythonPackage rec {
 
   dontUseCmakeConfigure = true;
 
-  CMAKE_ARGS = [ "-DEXTERNAL_PYBIND11=ON" ];
+  env.CMAKE_ARGS = toString [ "-DEXTERNAL_PYBIND11=ON" ];
 
   nativeCheckInputs = [
     graphviz
diff --git a/pkgs/development/python-modules/pylint-odoo/default.nix b/pkgs/development/python-modules/pylint-odoo/default.nix
index a43cb6fa4825..f8aaec5864ac 100644
--- a/pkgs/development/python-modules/pylint-odoo/default.nix
+++ b/pkgs/development/python-modules/pylint-odoo/default.nix
@@ -31,7 +31,7 @@ buildPythonPackage rec {
 
   pythonImportsCheck = [ "pylint_odoo" ];
 
-  BUILD_README = true; # Enables more tests
+  env.BUILD_README = true; # Enables more tests
 
   nativeCheckInputs = [ pytestCheckHook ];
 
diff --git a/pkgs/development/python-modules/pynest2d/default.nix b/pkgs/development/python-modules/pynest2d/default.nix
index 4e499fd47080..632101695f72 100644
--- a/pkgs/development/python-modules/pynest2d/default.nix
+++ b/pkgs/development/python-modules/pynest2d/default.nix
@@ -35,7 +35,7 @@ buildPythonPackage rec {
 
   strictDeps = true;
 
-  CLIPPER_PATH = "${clipper.out}";
+  env.CLIPPER_PATH = clipper.out;
 
   postPatch = ''
     sed -i 's#''${Python3_SITEARCH}#${placeholder "out"}/${python.sitePackages}#' cmake/SIPMacros.cmake
diff --git a/pkgs/development/python-modules/pysptk/default.nix b/pkgs/development/python-modules/pysptk/default.nix
index a84a3f090544..383c7fdccccb 100644
--- a/pkgs/development/python-modules/pysptk/default.nix
+++ b/pkgs/development/python-modules/pysptk/default.nix
@@ -20,7 +20,7 @@ buildPythonPackage rec {
     hash = "sha256-eLHJM4v3laQc3D/wP81GmcQBwyP1RjC7caGXEAeNCz8=";
   };
 
-  PYSPTK_BUILD_VERSION = 0;
+  env.PYSPTK_BUILD_VERSION = 0;
 
   nativeBuildInputs = [ cython ];
 
diff --git a/pkgs/development/python-modules/python-uinput/default.nix b/pkgs/development/python-modules/python-uinput/default.nix
index 25af52c42652..d2598e60f84b 100644
--- a/pkgs/development/python-modules/python-uinput/default.nix
+++ b/pkgs/development/python-modules/python-uinput/default.nix
@@ -17,7 +17,7 @@ buildPythonPackage rec {
 
   buildInputs = [ udev ];
 
-  NIX_CFLAGS_LINK = "-ludev";
+  env.NIX_CFLAGS_LINK = "-ludev";
 
   doCheck = false; # no tests
 
diff --git a/pkgs/development/python-modules/pytoolconfig/default.nix b/pkgs/development/python-modules/pytoolconfig/default.nix
index 0f5ef30d7c15..687c05a30b15 100644
--- a/pkgs/development/python-modules/pytoolconfig/default.nix
+++ b/pkgs/development/python-modules/pytoolconfig/default.nix
@@ -32,7 +32,7 @@ buildPythonPackage rec {
     "doc"
   ];
 
-  PDM_PEP517_SCM_VERSION = version;
+  env.PDM_PEP517_SCM_VERSION = version;
 
   nativeBuildInputs = [
     pdm-backend
diff --git a/pkgs/development/python-modules/qstylizer/default.nix b/pkgs/development/python-modules/qstylizer/default.nix
index 027e7c90c6eb..26e4012b189c 100644
--- a/pkgs/development/python-modules/qstylizer/default.nix
+++ b/pkgs/development/python-modules/qstylizer/default.nix
@@ -28,7 +28,7 @@ buildPythonPackage rec {
     hash = "sha256-Is/kYkSX9fOX+pLv5g1ns2OxeLpSkaCfO2jPIbiuIxA=";
   };
 
-  PBR_VERSION = version;
+  env.PBR_VERSION = version;
 
   build-system = [
     pbr
diff --git a/pkgs/development/python-modules/scikit-hep-testdata/default.nix b/pkgs/development/python-modules/scikit-hep-testdata/default.nix
index cfab7955bb02..f85f92abc28b 100644
--- a/pkgs/development/python-modules/scikit-hep-testdata/default.nix
+++ b/pkgs/development/python-modules/scikit-hep-testdata/default.nix
@@ -30,7 +30,7 @@ buildPythonPackage rec {
     requests
   ];
 
-  SKHEP_DATA = 1; # install the actual root files
+  env.SKHEP_DATA = 1; # install the actual root files
 
   doCheck = false; # tests require networking
 
diff --git a/pkgs/development/python-modules/scipy/default.nix b/pkgs/development/python-modules/scipy/default.nix
index 3bbd316e8178..1673a33becc2 100644
--- a/pkgs/development/python-modules/scipy/default.nix
+++ b/pkgs/development/python-modules/scipy/default.nix
@@ -243,7 +243,7 @@ buildPythonPackage (finalAttrs: {
     };
   };
 
-  SCIPY_USE_G77_ABI_WRAPPER = 1;
+  env.SCIPY_USE_G77_ABI_WRAPPER = 1;
 
   meta = {
     changelog = "https://github.com/scipy/scipy/releases/tag/v${finalAttrs.version}";
diff --git a/pkgs/development/python-modules/seccomp/default.nix b/pkgs/development/python-modules/seccomp/default.nix
index 951e4b31722a..07c6989957ca 100644
--- a/pkgs/development/python-modules/seccomp/default.nix
+++ b/pkgs/development/python-modules/seccomp/default.nix
@@ -11,7 +11,7 @@ buildPythonPackage rec {
   format = "setuptools";
   src = libseccomp.pythonsrc;
 
-  VERSION_RELEASE = version; # used by build system
+  env.VERSION_RELEASE = version; # used by build system
 
   nativeBuildInputs = [ cython ];
   buildInputs = [ libseccomp ];
diff --git a/pkgs/development/python-modules/shiboken2/default.nix b/pkgs/development/python-modules/shiboken2/default.nix
index 998e04cc03fc..9adee3dd4187 100644
--- a/pkgs/development/python-modules/shiboken2/default.nix
+++ b/pkgs/development/python-modules/shiboken2/default.nix
@@ -29,7 +29,7 @@ stdenv.mkDerivation {
     head CMakeLists.txt
   '';
 
-  CLANG_INSTALL_DIR = llvmPackages.libclang.out;
+  env.CLANG_INSTALL_DIR = llvmPackages.libclang.out;
 
   nativeBuildInputs = [
     cmake
diff --git a/pkgs/development/python-modules/svgdigitizer/default.nix b/pkgs/development/python-modules/svgdigitizer/default.nix
index 99e363c86928..1e44d9a5f7d7 100644
--- a/pkgs/development/python-modules/svgdigitizer/default.nix
+++ b/pkgs/development/python-modules/svgdigitizer/default.nix
@@ -59,7 +59,7 @@ buildPythonPackage rec {
     svgwrite
   ];
   # https://github.com/echemdb/svgdigitizer/issues/252
-  MPLBACKEND = "Agg";
+  env.MPLBACKEND = "Agg";
 
   nativeCheckInputs = [
     pytestCheckHook
diff --git a/pkgs/development/python-modules/tiledb/default.nix b/pkgs/development/python-modules/tiledb/default.nix
index 1ea6bd3d78ec..1b870af5d2c0 100644
--- a/pkgs/development/python-modules/tiledb/default.nix
+++ b/pkgs/development/python-modules/tiledb/default.nix
@@ -59,7 +59,7 @@ buildPythonPackage rec {
     pyarrow
   ];
 
-  TILEDB_PATH = tiledb;
+  env.TILEDB_PATH = tiledb;
 
   disabled = !isPy3k; # Not bothering with python2 anymore
 
diff --git a/pkgs/development/python-modules/tinycss/default.nix b/pkgs/development/python-modules/tinycss/default.nix
index d1023487c715..5419f93a0010 100644
--- a/pkgs/development/python-modules/tinycss/default.nix
+++ b/pkgs/development/python-modules/tinycss/default.nix
@@ -36,7 +36,7 @@ buildPythonPackage rec {
   '';
 
   # Disable Cython tests
-  TINYCSS_SKIP_SPEEDUPS_TESTS = true;
+  env.TINYCSS_SKIP_SPEEDUPS_TESTS = true;
 
   pythonImportsCheck = [ "tinycss" ];
 
diff --git a/pkgs/development/python-modules/tmb/default.nix b/pkgs/development/python-modules/tmb/default.nix
index ae9bc95d14f8..2481bdb8f71e 100644
--- a/pkgs/development/python-modules/tmb/default.nix
+++ b/pkgs/development/python-modules/tmb/default.nix
@@ -17,7 +17,7 @@ buildPythonPackage rec {
     hash = "sha256-XuRhRmeTXAplb14UwISyzaqEIrFeg8/aCdMxUccMUos=";
   };
 
-  VERSION = version;
+  env.VERSION = version;
 
   propagatedBuildInputs = [ requests ];
 
diff --git a/pkgs/development/python-modules/torchaudio/default.nix b/pkgs/development/python-modules/torchaudio/default.nix
index 581f288a5236..4f5e02968940 100644
--- a/pkgs/development/python-modules/torchaudio/default.nix
+++ b/pkgs/development/python-modules/torchaudio/default.nix
@@ -99,16 +99,19 @@ buildPythonPackage.override { inherit stdenv; } (finalAttrs: {
 
   env = {
     TORCH_CUDA_ARCH_LIST = "${lib.concatStringsSep ";" torch.cudaCapabilities}";
-  };
-
-  # https://github.com/pytorch/audio/blob/v2.1.0/docs/source/build.linux.rst#optional-build-torchaudio-with-a-custom-built-ffmpeg
-  FFMPEG_ROOT = symlinkJoin {
-    name = "ffmpeg";
-    paths = [
-      ffmpeg_6-full.bin
-      ffmpeg_6-full.dev
-      ffmpeg_6-full.lib
-    ];
+    # https://github.com/pytorch/audio/blob/v2.1.0/docs/source/build.linux.rst#optional-build-torchaudio-with-a-custom-built-ffmpeg
+    FFMPEG_ROOT = symlinkJoin {
+      name = "ffmpeg";
+      paths = [
+        ffmpeg_6-full.bin
+        ffmpeg_6-full.dev
+        ffmpeg_6-full.lib
+      ];
+    };
+    BUILD_SOX = 0;
+    BUILD_KALDI = 0;
+    BUILD_RNNT = 0;
+    BUILD_CTC_DECODER = 0;
   };
 
   nativeBuildInputs = [
@@ -136,11 +139,6 @@ buildPythonPackage.override { inherit stdenv; } (finalAttrs: {
 
   dependencies = [ torch ];
 
-  BUILD_SOX = 0;
-  BUILD_KALDI = 0;
-  BUILD_RNNT = 0;
-  BUILD_CTC_DECODER = 0;
-
   preConfigure = lib.optionalString rocmSupport ''
     export ROCM_PATH=${rocmtoolkit_joined}
     export PYTORCH_ROCM_ARCH="${gpuTargetString}"
diff --git a/pkgs/development/python-modules/unrardll/default.nix b/pkgs/development/python-modules/unrardll/default.nix
index 2eea89693ca8..1bacabbd1628 100644
--- a/pkgs/development/python-modules/unrardll/default.nix
+++ b/pkgs/development/python-modules/unrardll/default.nix
@@ -18,7 +18,9 @@ buildPythonPackage rec {
 
   buildInputs = [ unrar ];
 
-  NIX_CFLAGS_LINK = lib.optionalString stdenv.hostPlatform.isDarwin "-headerpad_max_install_names";
+  env = lib.optionalAttrs stdenv.hostPlatform.isDarwin {
+    NIX_CFLAGS_LINK = "-headerpad_max_install_names";
+  };
 
   postInstall = lib.optionalString stdenv.hostPlatform.isDarwin ''
     install_name_tool -change libunrar.so ${unrar}/lib/libunrar.so $out/lib/python*/site-packages/unrardll/unrar.*-darwin.so
diff --git a/pkgs/development/python-modules/weasyprint/default.nix b/pkgs/development/python-modules/weasyprint/default.nix
index bf076964b914..40c26569dc1d 100644
--- a/pkgs/development/python-modules/weasyprint/default.nix
+++ b/pkgs/development/python-modules/weasyprint/default.nix
@@ -103,10 +103,10 @@ buildPythonPackage (finalAttrs: {
     "test_text_stroke"
   ];
 
-  FONTCONFIG_FILE = "${fontconfig.out}/etc/fonts/fonts.conf";
+  env.FONTCONFIG_FILE = "${fontconfig.out}/etc/fonts/fonts.conf";
 
   # Set env variable explicitly for Darwin, but allow overriding when invoking directly
-  makeWrapperArgs = [ "--set-default FONTCONFIG_FILE ${finalAttrs.FONTCONFIG_FILE}" ];
+  makeWrapperArgs = [ "--set-default FONTCONFIG_FILE ${finalAttrs.env.FONTCONFIG_FILE}" ];
 
   pythonImportsCheck = [ "weasyprint" ];
 
diff --git a/pkgs/development/python-modules/xgrammar/default.nix b/pkgs/development/python-modules/xgrammar/default.nix
index fb44ff711e69..adced646dc38 100644
--- a/pkgs/development/python-modules/xgrammar/default.nix
+++ b/pkgs/development/python-modules/xgrammar/default.nix
@@ -70,10 +70,12 @@ buildPythonPackage rec {
     writableTmpDirAsHomeHook
   ];
 
-  NIX_CFLAGS_COMPILE = lib.optionalString stdenv.hostPlatform.isLinux (toString [
-    # xgrammar hardcodes -flto=auto while using static linking, which can cause linker errors without this additional flag.
-    "-ffat-lto-objects"
-  ]);
+  env = lib.optionalAttrs stdenv.hostPlatform.isLinux {
+    NIX_CFLAGS_COMPILE = toString [
+      # xgrammar hardcodes -flto=auto while using static linking, which can cause linker errors without this additional flag.
+      "-ffat-lto-objects"
+    ];
+  };
 
   disabledTests = [
     # You are trying to access a gated repo.
diff --git a/pkgs/development/python-modules/zstd/default.nix b/pkgs/development/python-modules/zstd/default.nix
index a2b7a7ed3006..b2ad8de91863 100644
--- a/pkgs/development/python-modules/zstd/default.nix
+++ b/pkgs/development/python-modules/zstd/default.nix
@@ -33,10 +33,12 @@ buildPythonPackage rec {
     "--library-dirs=${zstd}/lib"
   ];
 
-  # Running tests via setup.py triggers an attempt to recompile with the vendored zstd
-  ZSTD_EXTERNAL = 1;
-  VERSION = zstd.version;
-  PKG_VERSION = version;
+  env = {
+    # Running tests via setup.py triggers an attempt to recompile with the vendored zstd
+    ZSTD_EXTERNAL = 1;
+    VERSION = zstd.version;
+    PKG_VERSION = version;
+  };
 
   nativeCheckInputs = [ pytest ];
   checkPhase = ''