diff --git a/src/client/shared/requests/xmlhttprequest.ts b/src/client/shared/requests/xmlhttprequest.ts
index 1390794..cc59564 100644
--- a/src/client/shared/requests/xmlhttprequest.ts
+++ b/src/client/shared/requests/xmlhttprequest.ts
@@ -26,6 +26,12 @@ export default function (client: ScramjetClient, self: Self) {
 			const args = ctx.this[ARGS];
 			if (!args || args[2]) return;
 
+			if (!self.$scramjet.config.flags.syncxhr) {
+				console.warn("sync xhr disabled in flags");
+
+				return;
+			}
+
 			// it's a sync request
 			// sync xhr to service worker is not supported
 			// there's a nice way of polyfilling this though, we can spin on an atomic using sharedarraybuffer. this will maintain the sync behavior
diff --git a/src/controller/index.ts b/src/controller/index.ts
index 58bad7f..6dfafd9 100644
--- a/src/controller/index.ts
+++ b/src/controller/index.ts
@@ -31,6 +31,7 @@ export class ScramjetController {
 				serviceworkers: false,
 				naiiveRewriter: false,
 				captureErrors: true,
+				syncxhr: false,
 				cleanerrors: false,
 				sourcemaps: false,
 			},
diff --git a/src/types.d.ts b/src/types.d.ts
index 3e0283a..f460692 100644
--- a/src/types.d.ts
+++ b/src/types.d.ts
@@ -25,6 +25,7 @@ type ScramjetFlags = {
 	captureErrors: boolean;
 	cleanerrors: boolean;
 	sourcemaps: boolean;
+	syncxhr: boolean;
 };
 
 interface ScramjetConfig {