diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 8010cec37..ee48db8f7 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -33,6 +33,11 @@ jobs:
       - name: Run ESLint
         run: npm run lint
 
+      # Enforces the Swiss umlaut convention (display text keeps ä/ö/ü; only
+      # code identifiers/slugs may use ASCII). Was manual-only before — now gated.
+      - name: Check umlauts
+        run: npm run lint:umlauts
+
       - name: Type check
         run: npx tsc --noEmit
 
diff --git a/.github/workflows/deploy-selfhost.yml b/.github/workflows/deploy-selfhost.yml
index 5a09a86f6..22ea8420e 100644
--- a/.github/workflows/deploy-selfhost.yml
+++ b/.github/workflows/deploy-selfhost.yml
@@ -70,6 +70,10 @@ jobs:
         if: steps.secrets.outputs.configured == 'true'
         run: npm run lint
 
+      - name: Check umlauts
+        if: steps.secrets.outputs.configured == 'true'
+        run: npm run lint:umlauts
+
       - name: Type check
         if: steps.secrets.outputs.configured == 'true'
         run: npm run typecheck