diff --git a/website/astro.config.mjs b/website/astro.config.mjs
index d0fb568..f1fc430 100644
--- a/website/astro.config.mjs
+++ b/website/astro.config.mjs
@@ -1,4 +1,4 @@
-import { defineConfig } from "astro/config";
+import { defineConfig, envField } from "astro/config";
 import mdx from "@astrojs/mdx";
 import node from "@astrojs/node";
 
@@ -9,6 +9,11 @@ export default defineConfig({
   adapter: node({
     mode: "standalone",
   }),
+  env: {
+    schema: {
+      SENDMAIL_BIN: envField.string({ context: "server", access: "secret" }),
+    },
+  },
   site: "https://joeac.net",
   integrations: [mdx(), sitemap()],
 });