diff --git a/.github/workflows/publish.yml b/.github/workflows/publish.yml
index 8fc0de773..220b7fead 100644
--- a/.github/workflows/publish.yml
+++ b/.github/workflows/publish.yml
@@ -26,8 +26,16 @@ jobs:
       - run: |
           set -eux
 
-          nix flake check --all-systems
+          # Ensure all the checks can be built without internet
+          nix flake check --all-systems --jobs 0
+          nix build .#tarballs_json
+          cat result
+
+          nix build .#closures_json
+          cat result
+
           nix build .#closures_nix
+          cat result
 
           mkdir ./artifacts
           cat './result' > './artifacts/universal'
diff --git a/flake.nix b/flake.nix
index 81ecf86cf..f0799d8f6 100644
--- a/flake.nix
+++ b/flake.nix
@@ -26,11 +26,23 @@
     in
     {
       closures = forAllSystems ({ system, ... }: nix.packages."${system}".default);
+      tarballs = forAllSystems ({ system, ... }: nix.checks."${system}".binaryTarball);
+
       checks = forAllSystems ({ system, ... }: {
-        fetchable = nix.packages."${system}".default;
+        closure = nix.packages."${system}".default;
+        tarball = nix.checks."${system}".binaryTarball;
       });
 
       packages = forAllSystems ({ system, pkgs, ... }: {
+        tarballs_json = pkgs.runCommand "tarballs.json"
+          {
+            buildInputs = [ pkgs.jq ];
+            passAsFile = [ "json" ];
+            json = builtins.toJSON (self.tarballs);
+          } ''
+          cat "$jsonPath" | jq . > $out
+        '';
+
         closures_json = pkgs.runCommand "versions.json"
           {
             buildInputs = [ pkgs.jq ];