diff --git a/packages/format-errors/src/index.ts b/packages/format-errors/src/index.ts
index d620a7d37ad3..e5dfd10a2e2a 100644
--- a/packages/format-errors/src/index.ts
+++ b/packages/format-errors/src/index.ts
@@ -155,8 +155,16 @@ export default {
 				},
 			},
 		});
+
+		// Validate payload outside of Sentry/metrics reporting
+		let payload: Payload;
+		try {
+			payload = PayloadSchema.parse(await request.json());
+		} catch {
+			return new Response("Invalid payload", { status: 400 });
+		}
+
 		try {
-			const payload = PayloadSchema.parse(await request.json());
 			return handlePrettyErrorRequest(payload);
 		} catch (e) {
 			sentry.captureException(e);