diff --git a/nix/.nixpkgs/config.nix b/nix/.nixpkgs/config.nix
index a41e28f..a901acd 100644
--- a/nix/.nixpkgs/config.nix
+++ b/nix/.nixpkgs/config.nix
@@ -20,6 +20,7 @@
               Spock
               stack
               stylish-haskell
+              regex-posix
               wreq
               ]
           );