diff --git a/flake.nix b/flake.nix
index 90d8ab6..5c04274 100644
--- a/flake.nix
+++ b/flake.nix
@@ -20,6 +20,14 @@
           packages = [
             python
             pkgs.python311Packages.virtualenv  # gives `virtualenv` tool
+            pkgs.zlib
+            pkgs.stdenv.cc.cc.lib
+          ];
+
+          # Required for numpy and other C extension packages
+          LD_LIBRARY_PATH = pkgs.lib.makeLibraryPath [
+            pkgs.zlib
+            pkgs.stdenv.cc.cc.lib
           ];
 
           shellHook = ''
diff --git a/requirements.txt b/requirements.txt
index edab150..a28fbb7 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -11,4 +11,5 @@ uvicorn[standard]
 httpx
 streamlit
 plotly
+numpy
 pandas