diff --git a/js/packages/binderhub-client/lib/index.js b/js/packages/binderhub-client/lib/index.js
index 2cd2a7d21..19d239304 100644
--- a/js/packages/binderhub-client/lib/index.js
+++ b/js/packages/binderhub-client/lib/index.js
@@ -25,14 +25,11 @@ export class BinderRepository {
    * Call the BinderHub API
    */
   fetch() {
-    let apiUrl =  new URL(this.baseUrl + "build/" + this.providerSpec);
-    let params = new URLSearchParams();
+    let apiUrl = this.baseUrl + "build/" + this.providerSpec;
     if (this.buildToken) {
-        params.append('build_token', this.buildToken);
+        apiUrl = apiUrl + `?build_token=${this.buildToken}`;
     }
 
-    apiUrl.search = params.toString();
-
     this.eventSource = new EventSource(apiUrl);
     this.eventSource.onerror = (err) => {
       console.error("Failed to construct event stream", err);