diff --git a/plugins/proxy-sigv4-backend/src/service/router.test.ts b/plugins/proxy-sigv4-backend/src/service/router.test.ts
index 05d06ca..8ee1292 100644
--- a/plugins/proxy-sigv4-backend/src/service/router.test.ts
+++ b/plugins/proxy-sigv4-backend/src/service/router.test.ts
@@ -224,7 +224,7 @@ describe('buildMiddleware', () => {
         expiration: new Date('2024-05-05T20:30:00Z'),
       });
 
-    // s
+    // starts the middleware and timer
     await buildMiddleware({
       logger,
       routePath: '/foo',
diff --git a/plugins/proxy-sigv4-backend/src/service/router.ts b/plugins/proxy-sigv4-backend/src/service/router.ts
index 83f2229..1acae73 100644
--- a/plugins/proxy-sigv4-backend/src/service/router.ts
+++ b/plugins/proxy-sigv4-backend/src/service/router.ts
@@ -189,10 +189,9 @@ export async function buildMiddleware(
         headers: requestHeaders,
       };
 
-      if (req.method !== 'GET' && req.method !== 'HEAD') {
-        request.body = req.is('application/json')
-          ? JSON.stringify(req.body)
-          : req.body;
+      // TODO: support other content types with bodies
+      if (req.is('application/json') && req.method !== 'GET') {
+        request.body = JSON.stringify(req.body);
       }
 
       aws4.sign(request, credentials);