diff --git a/packages/superset-ui-connection/src/SupersetClientClass.ts b/packages/superset-ui-connection/src/SupersetClientClass.ts
index 461147c3d0..08fa0b8424 100644
--- a/packages/superset-ui-connection/src/SupersetClientClass.ts
+++ b/packages/superset-ui-connection/src/SupersetClientClass.ts
@@ -31,7 +31,7 @@ import {
   RequestConfig,
   ParseMethod,
 } from './types';
-import { DEFAULT_FETCH_RETRY_OPTIONS } from './constants';
+import { DEFAULT_FETCH_RETRY_OPTIONS, DEFAULT_BASE_URL } from './constants';
 
 export default class SupersetClientClass {
   credentials: Credentials;
@@ -46,7 +46,7 @@ export default class SupersetClientClass {
   timeout: ClientTimeout;
 
   constructor({
-    baseUrl = 'http://localhost',
+    baseUrl = DEFAULT_BASE_URL,
     host,
     protocol,
     headers = {},
@@ -60,7 +60,7 @@ export default class SupersetClientClass {
       host || protocol ? `${protocol || 'https:'}//${host || 'localhost'}` : baseUrl,
       // baseUrl for API could also be relative, so we provide current location.href
       // as the base of baseUrl
-      window.location.href || 'http://localhost',
+      window.location.href || DEFAULT_BASE_URL,
     );
     this.baseUrl = url.href.replace(/\/+$/, ''); // always strip trailing slash
     this.host = url.host;
diff --git a/packages/superset-ui-connection/src/callApi/callApi.ts b/packages/superset-ui-connection/src/callApi/callApi.ts
index 2f20249c1a..8e9ddf2d28 100644
--- a/packages/superset-ui-connection/src/callApi/callApi.ts
+++ b/packages/superset-ui-connection/src/callApi/callApi.ts
@@ -1,7 +1,13 @@
 import 'whatwg-fetch';
 import fetchRetry from 'fetch-retry';
 import { CallApi, Payload, JsonValue } from '../types';
-import { CACHE_AVAILABLE, CACHE_KEY, HTTP_STATUS_NOT_MODIFIED, HTTP_STATUS_OK } from '../constants';
+import {
+  CACHE_AVAILABLE,
+  CACHE_KEY,
+  HTTP_STATUS_NOT_MODIFIED,
+  HTTP_STATUS_OK,
+  DEFAULT_BASE_URL,
+} from '../constants';
 
 function tryParsePayload(payload: Payload) {
   try {
@@ -16,7 +22,7 @@ function tryParsePayload(payload: Payload) {
  */
 function getFullUrl(partialUrl: string, params: CallApi['searchParams']) {
   if (params) {
-    const url = new URL(partialUrl, window.location.href);
+    const url = new URL(partialUrl, window.location.href || DEFAULT_BASE_URL);
     const search = params instanceof URLSearchParams ? params : new URLSearchParams(params);
     // will completely override any existing search params
     url.search = search.toString();
diff --git a/packages/superset-ui-connection/src/constants.ts b/packages/superset-ui-connection/src/constants.ts
index e856f48898..c0c9bd01f9 100644
--- a/packages/superset-ui-connection/src/constants.ts
+++ b/packages/superset-ui-connection/src/constants.ts
@@ -1,5 +1,7 @@
 import { FetchRetryOptions } from './types';
 
+export const DEFAULT_BASE_URL = 'http://localhost';
+
 // HTTP status codes
 export const HTTP_STATUS_OK = 200;
 export const HTTP_STATUS_NOT_MODIFIED = 304;