diff --git a/flake.nix b/flake.nix
index 9775e04..1f52d38 100644
--- a/flake.nix
+++ b/flake.nix
@@ -21,6 +21,9 @@
       devShells = forAllSystems (pkgs: {
         default = pkgs.mkShell {
           packages = with pkgs; [
+            python3
+            python3Packages.cocotb
+            python3Packages.cocotb-bus
             yosys
             nextpnr
             # simulators