diff --git a/apps/backend/src/lib/mailer.ts b/apps/backend/src/lib/mailer.ts
index 50434b6..0d57130 100644
--- a/apps/backend/src/lib/mailer.ts
+++ b/apps/backend/src/lib/mailer.ts
@@ -16,7 +16,7 @@ function getTransporter() {
     MailtrapTransport({
       token: TOKEN,
       sandbox: Bun.env.MAIL_SANDBOX === 'true',
-      testInboxId: 1114587
+      testInboxId: Bun.env.MAIL_INBOX_ID ? Number(Bun.env.MAIL_INBOX_ID) : undefined,
     })
   );
   return cachedTransporter;