diff --git a/src/util/webhook.ts b/src/util/webhook.ts
index 92915b1..fdf218f 100644
--- a/src/util/webhook.ts
+++ b/src/util/webhook.ts
@@ -21,6 +21,7 @@ export async function sendWebhook<T extends WebhookAction>(action: T, data: Webh
         body: JSON.stringify(data),
         method: 'POST',
         headers: {
+          'Content-Type': 'application/json',
           'x-webhook-action': action
         },
         keepalive: false