diff --git a/.gitignore b/.gitignore
index 430a8c8720..5fe70512df 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,6 +1,7 @@
 .idea
 .env
 .envrc
+.direnv
 __pycache__
 binaries/*
 !binaries/README.md
diff --git a/default.nix b/default.nix
new file mode 100644
index 0000000000..f8629f43ba
--- /dev/null
+++ b/default.nix
@@ -0,0 +1,12 @@
+# flake-compat shim for usage without flakes
+(import
+  (
+    let lock = builtins.fromJSON (builtins.readFile ./flake.lock); in
+    fetchTarball {
+      url = lock.nodes.flake-compat.locked.url or "https://github.com/edolstra/flake-compat/archive/${lock.nodes.flake-compat.locked.rev}.tar.gz";
+      sha256 = lock.nodes.flake-compat.locked.narHash;
+    }
+  )
+  { src = ./.; }
+).defaultNix
+
diff --git a/flake.lock b/flake.lock
new file mode 100644
index 0000000000..e20463ede2
--- /dev/null
+++ b/flake.lock
@@ -0,0 +1,76 @@
+{
+  "nodes": {
+    "flake-compat": {
+      "locked": {
+        "lastModified": 1696426674,
+        "narHash": "sha256-kvjfFW7WAETZlt09AgDn1MrtKzP7t90Vf7vypd3OL1U=",
+        "rev": "0f9255e01c2351cc7d116c072cb317785dd33b33",
+        "revCount": 57,
+        "type": "tarball",
+        "url": "https://api.flakehub.com/f/pinned/edolstra/flake-compat/1.0.1/018afb31-abd1-7bff-a5e4-cff7e18efb7a/source.tar.gz"
+      },
+      "original": {
+        "type": "tarball",
+        "url": "https://flakehub.com/f/edolstra/flake-compat/1.tar.gz"
+      }
+    },
+    "flake-utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1726560853,
+        "narHash": "sha256-X6rJYSESBVr3hBoH0WbKE5KvhPU5bloyZ2L4K60/fPQ=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "c1dfcf08411b08f6b8615f7d8971a2bfa81d5e8a",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1729239738,
+        "narHash": "sha256-JMCUax/2NQYflc9tQ2kmMNpxI3BZPvtvceoFExpwTng=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "a8f84a9dffb7805a2668004e1a3e427bdbc48413",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "master",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-compat": "flake-compat",
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs"
+      }
+    },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}
diff --git a/flake.nix b/flake.nix
new file mode 100644
index 0000000000..5a131b9dbe
--- /dev/null
+++ b/flake.nix
@@ -0,0 +1,65 @@
+{
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs/master";
+
+    # cross-platform convenience
+    flake-utils.url = "github:numtide/flake-utils";
+
+    # backwards compatibility with nix-build and nix-shell
+    flake-compat.url = "https://flakehub.com/f/edolstra/flake-compat/1.tar.gz";
+  };
+
+  outputs = { self, nixpkgs, flake-utils, flake-compat }:
+    # resolve for all platforms in turn
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        # packages for this system platform
+        pkgs = nixpkgs.legacyPackages.${system};
+
+        # control versions
+
+        # get these python packages from nix
+        python_packages = python-packages: [
+          python-packages.pip
+        ];
+
+        # use this pyton version, and include the abvoe packages
+        python = pkgs.python312.withPackages python_packages;
+      in {
+        devShell = pkgs.stdenv.mkDerivation {
+          name = "devshell";
+
+          buildInputs = with pkgs; [
+            # version to use + default packages are declared above
+            python
+
+
+            # linters
+            shellcheck
+
+            # for scripts
+            bash
+            fswatch
+            rsync
+          ] ++ lib.optionals (pkgs.stdenv.isDarwin) [
+            # for python watchdog package
+            darwin.apple_sdk.frameworks.CoreServices
+          ];
+
+
+          shellHook = ''
+            export PYTHON_VERSION="$(python -c 'import platform; import re; print(re.sub(r"\.\d+$", "", platform.python_version()))')"
+
+            # replicate virtualenv behaviour
+            export PIP_PREFIX="$PWD/vendor/python/$PYTHON_VERSION/packages"
+            export PYTHONPATH="$PIP_PREFIX/lib/python$PYTHON_VERSION/site-packages:$PYTHONPATH"
+            unset SOURCE_DATE_EPOCH
+            export PATH="$PIP_PREFIX/bin:$PATH"
+
+            # hack: can't find libstdc++.so.8 otherwise
+            export LD_LIBRARY_PATH="${pkgs.stdenv.cc.cc.lib}/lib"
+          '';
+        };
+      }
+    );
+}
diff --git a/shell.nix b/shell.nix
index 6bda0280d2..950c1c8180 100644
--- a/shell.nix
+++ b/shell.nix
@@ -1,45 +1,11 @@
-{
-  # use the environment channel
-  pkgs ? import <nixpkgs> {},
-
-  # use a pinned package state
-  pinned ? import(fetchTarball("https://github.com/NixOS/nixpkgs/archive/c75037bbf909.tar.gz")) {},
-}:
-let
-  # get these python packages from nix
-  python_packages = python-packages: [
-    python-packages.pip
-  ];
-
-  # use this pyton version, and include the abvoe packages
-  python = pinned.python39.withPackages python_packages;
-in pinned.stdenv.mkDerivation {
-  # unique project name for this environment derivation
-  name = "system-tests.devshell";
-
-  buildInputs = [
-    # version to use + default packages are declared above
-    python
-
-    # linters
-    pinned.shellcheck
-
-    # for scripts
-    pinned.bash
-    pinned.fswatch
-    pinned.rsync
-  ];
-
-  shellHook = ''
-    export PYTHON_VERSION="$(python -c 'import platform; import re; print(re.sub(r"\.\d+$", "", platform.python_version()))')"
-
-    # replicate virtualenv behaviour
-    export PIP_PREFIX="$PWD/vendor/python/$PYTHON_VERSION/packages"
-    export PYTHONPATH="$PIP_PREFIX/lib/python$PYTHON_VERSION/site-packages:$PYTHONPATH"
-    unset SOURCE_DATE_EPOCH
-    export PATH="$PIP_PREFIX/bin:$PATH"
-
-    # hack: can't find libstdc++.so.8 otherwise
-    export LD_LIBRARY_PATH="${pinned.stdenv.cc.cc.lib}/lib"
-  '';
-}
+# flake-compat shim for usage without flakes
+(import
+  (
+    let lock = builtins.fromJSON (builtins.readFile ./flake.lock); in
+    fetchTarball {
+      url = lock.nodes.flake-compat.locked.url or "https://github.com/edolstra/flake-compat/archive/${lock.nodes.flake-compat.locked.rev}.tar.gz";
+      sha256 = lock.nodes.flake-compat.locked.narHash;
+    }
+  )
+  { src = ./.; }
+).shellNix
diff --git a/utils/scripts/compute_impacted_scenario.py b/utils/scripts/compute_impacted_scenario.py
index 4dcbe22814..216799f567 100644
--- a/utils/scripts/compute_impacted_scenario.py
+++ b/utils/scripts/compute_impacted_scenario.py
@@ -179,7 +179,9 @@ def main():
                     r"format\.sh": None,
                     r"pyproject\.toml": None,
                     r"scenario_groups\.yml": None,
-                    r"shell\.nix": None,
+                    ## Nix
+                    r".*\.nix": None,
+                    r"flake\.lock": None,
                     ## few files with lot of effect
                     r"requirements\.txt": ScenarioGroup.ALL.value,
                     r"run\.sh": ScenarioGroup.ALL.value,