diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 925b731..4d5d56e 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -2,7 +2,8 @@ image: nixpkgs/nix-flakes
 
 workflow:
   rules:
-    - if: $CI_COMMIT_BRANCH
+    - if: $CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH
+    - if: $CI_MERGE_REQUEST_ID
 
 variables:
   STACK_ROOT: "${CI_PROJECT_DIR}/.stack-root"
@@ -13,6 +14,10 @@ cache:
     - .stack-root
     - _cache
 
+stages:
+  - review
+  - deploy
+
 pages:
   stage: deploy
   script: &build-script
@@ -21,13 +26,30 @@ pages:
     paths:
       - public
   rules:
-    - if: $CI_COMMIT_BRANCH == "main"
+    - if: $CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH
 
-test:
-  stage: test
+review:start:
+  stage: review
   script: *build-script
   artifacts:
     paths:
       - public
   rules:
-    - if: $CI_COMMIT_BRANCH != "main"
+    - if: $CI_MERGE_REQUEST_ID
+  environment:
+    name: preview/${CI_PROJECT_NAME}/${CI_COMMIT_REF_NAME}
+    url: https://${CI_PROJECT_NAMESPACE}.pages.uniworx.de/-/${CI_PROJECT_NAME}/-/jobs/${CI_JOB_ID}/artifacts/public/index.html
+    auto_stop_in: 2 weeks
+    on_stop: review:stop
+
+review:stop:
+  stage: review
+  rules:
+    - if: $CI_MERGE_REQUEST_ID
+      when: manual
+  allow_failure: true
+  environment:
+    name: preview/${CI_PROJECT_NAME}/${CI_COMMIT_REF_NAME}
+    action: stop
+  script:
+    - echo 'Terminating review app'
diff --git a/frontend/node_modules.gup b/frontend/node_modules.gup
index 5ce3bf5..6c123f3 100644
--- a/frontend/node_modules.gup
+++ b/frontend/node_modules.gup
@@ -1,5 +1,5 @@
 #!/usr/bin/env sh
 
 gup -u package.json yarn.lock
-yarn install
+yarn install --frozen-lockfile --check-files --non-interactive
 touch node_modules