diff --git a/src/api/client.ts b/src/api/client.ts
index 73713e2..2a1dc0f 100644
--- a/src/api/client.ts
+++ b/src/api/client.ts
@@ -28,7 +28,8 @@ interface RequestOptions {
 }
 
 function buildUrl(path: string, params?: ListParams): string {
-  const url = new URL(path, BASE_URL)
+  const base = BASE_URL || (typeof location !== 'undefined' ? location.origin : 'http://localhost')
+  const url = new URL(path, base)
   if (params) {
     for (const [key, value] of Object.entries(params)) {
       if (value !== undefined && value !== null && value !== '') {