diff --git a/config/nix.nix b/config/nix.nix
index 78a4877f..bdf60db5 100644
--- a/config/nix.nix
+++ b/config/nix.nix
@@ -34,6 +34,7 @@ in {
       builders-use-substitutes = true;
       substituters = [
         "https://attic.chir.rs/chir-rs/"
+        "https://hydra.int.chir.rs"
       ];
       trusted-public-keys = [
         "nixcache:8KKuGz95Pk4UJ5W/Ni+pN+v+LDTkMMFV4yrGmAYgkDg="