diff --git a/circle.yml b/circle.yml
index 3c4355b..bd52288 100644
--- a/circle.yml
+++ b/circle.yml
@@ -17,7 +17,14 @@ jobs:
           name: Update rustc
           command: |
             rustup target add wasm32-unknown-unknown
+            rustup component add rustfmt-preview
             rustup update
+      - run:
+           name: Check formatting
+           command: |
+             rustfmt --version
+             cargo fmt
+             git diff --exit-code
       - run:
           name: Install dependencies
           command: |