diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 37281924..7d98e3ff 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -11,12 +11,4 @@ jobs:
         fetch-depth: 0
     - uses: cachix/install-nix-action@v12
     #- run: nix flake check
-    - run: nix-build -A checks.x86_64-linux.build
-  #validate-openapi:
-  #  runs-on: ubuntu-18.04
-  #  steps:
-  #  - uses: actions/checkout@v2
-  #    with:
-  #      fetch-depth: 0
-  #  - uses: cachix/install-nix-action@v12
-  #  - run: nix-shell -p openapi-generator-cli --run "openapi-generator-cli validate -i ./hydra-api.yaml"
+    - run: nix-build -A checks.x86_64-linux.build -A checks.x86_64-linux.validate-openapi
diff --git a/flake.nix b/flake.nix
index 0726140c..de4f29c5 100644
--- a/flake.nix
+++ b/flake.nix
@@ -482,11 +482,19 @@
             '';
           };
 
+        tests.validate-openapi = pkgs.runCommand "validate-openapi"
+          { buildInputs = [ pkgs.openapi-generator-cli ]; }
+          ''
+            openapi-generator-cli validate -i ${./hydra-api.yaml}
+            touch $out
+          '';
+
         container = nixosConfigurations.container.config.system.build.toplevel;
       };
 
       checks.x86_64-linux.build = hydraJobs.build.x86_64-linux;
       checks.x86_64-linux.install = hydraJobs.tests.install.x86_64-linux;
+      checks.x86_64-linux.validate-openapi = hydraJobs.tests.validate-openapi;
 
       packages.x86_64-linux.hydra = pkgs.hydra;
       defaultPackage.x86_64-linux = pkgs.hydra;