diff --git a/.gitea/workflows/deploy-dev.yaml b/.gitea/workflows/deploy-dev.yaml
index b3747f4..b66787e 100644
--- a/.gitea/workflows/deploy-dev.yaml
+++ b/.gitea/workflows/deploy-dev.yaml
@@ -24,3 +24,8 @@ jobs:
 
       - name: Copy .env.example to .env
         run: cp functions/.env.example functions/.env
+
+      - name: Replace MAILGUN_API_KEY in .env
+        run: |
+          sed -i "s/#{MAILGUN_API_KEY}#/${MAILGUN_API_KEY}/" functions/.env
+          sed -i "s/#{MAILGUN_SERVER}#/${MAILGUN_SERVER}/" functions/.env