diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
new file mode 100644
index 0000000000..7c3ad003fc
--- /dev/null
+++ b/.gitlab-ci.yml
@@ -0,0 +1,9 @@
+nixCache:
+  image: "nixos/nix:latest"
+  script:
+    - "test -d cache || mkdir cache"
+    - "nix-build -f ./ci-root.nix --option extra-substituters \"s3://lukegb-nix-cache?endpoint=storage.googleapis.com file://$PWD/cache\""
+    - "nix copy --to 'file://cache' -f ./ci-root.nix"
+    - "nix copy --to 's3://lukegb-nix-cache?endpoint=storage.googleapis.com' -f ./ci-root.nix"
+  cache:
+    key: one-key-to-rule-them-all
diff --git a/ci-root.nix b/ci-root.nix
new file mode 100644
index 0000000000..89a002fdab
--- /dev/null
+++ b/ci-root.nix
@@ -0,0 +1,3 @@
+with (import ./default.nix {}); [
+  ops.nixos
+]