diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 27e481199bdc6a2e755989bc612b9b6a203adc5a..a942c57e8cfb2516dfc263c070f71ab876dd96a0 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -58,7 +58,7 @@ fmt:
     - export PATH="$HOME/.cargo/bin:$PATH"
     - cargo install --force rustfmt-nightly
   script:
-    - cargo fmt -- --write-mode=diff
+    - cargo fmt -- --check
   allow_failure: true
 
 publish:crate: