diff --git a/google-api-client/src/main/java/com/google/api/client/googleapis/services/AbstractGoogleClient.java b/google-api-client/src/main/java/com/google/api/client/googleapis/services/AbstractGoogleClient.java
index beb2c9260..5b4fea0ec 100644
--- a/google-api-client/src/main/java/com/google/api/client/googleapis/services/AbstractGoogleClient.java
+++ b/google-api-client/src/main/java/com/google/api/client/googleapis/services/AbstractGoogleClient.java
@@ -25,6 +25,7 @@
 import com.google.common.annotations.VisibleForTesting;
 import java.io.IOException;
 import java.util.logging.Logger;
+import java.util.regex.Pattern;
 
 /**
  * Abstract thread-safe Google client.
@@ -405,6 +406,13 @@ public abstract static class Builder {
     /** User configured Universe Domain. Defaults to `googleapis.com`. */
     String universeDomain;
 
+    /**
+     * Regex pattern to check if the URL passed in matches the default endpoint confgured from a
+     * discovery doc. Follows the format of `https://{serviceName}(.mtls).googleapis.com/`
+     */
+    Pattern defaultEndpointRegex =
+        Pattern.compile("https://[a-zA-Z]*(\\.mtls)?\\.googleapis.com/?");
+
     /**
      * Whether the user has configured an endpoint via {@link #setRootUrl(String)}. This is added in
      * because the rootUrl is set in the Builder's constructor. ,
@@ -443,8 +451,7 @@ protected Builder(
       this.servicePath = normalizeServicePath(servicePath);
       this.httpRequestInitializer = httpRequestInitializer;
       this.serviceName = parseServiceName(rootUrl);
-      this.isUserConfiguredEndpoint =
-          !this.rootUrl.endsWith(Credentials.GOOGLE_DEFAULT_UNIVERSE + "/");
+      this.isUserConfiguredEndpoint = !defaultEndpointRegex.matcher(this.rootUrl).matches();
     }
 
     /**
diff --git a/google-api-client/src/test/java/com/google/api/client/googleapis/services/AbstractGoogleClientTest.java b/google-api-client/src/test/java/com/google/api/client/googleapis/services/AbstractGoogleClientTest.java
index 8676ad98d..6145f7e69 100644
--- a/google-api-client/src/test/java/com/google/api/client/googleapis/services/AbstractGoogleClientTest.java
+++ b/google-api-client/src/test/java/com/google/api/client/googleapis/services/AbstractGoogleClientTest.java
@@ -289,6 +289,15 @@ public void testInitialize() throws Exception {
     assertTrue(remoteRequestInitializer.isCalled);
   }
 
+  @Test
+  public void testParseServiceName_nonMtlsRootUrl() {
+    AbstractGoogleClient.Builder clientBuilder =
+        new MockGoogleClient.Builder(
+                TRANSPORT, "https://random.googleapis.com/", "", JSON_OBJECT_PARSER, null)
+            .setApplicationName("Test Application");
+    assertEquals(clientBuilder.getServiceName(), "random");
+  }
+
   @Test
   public void testParseServiceName_mtlsRootUrl() {
     AbstractGoogleClient.Builder clientBuilder =
@@ -299,21 +308,52 @@ public void testParseServiceName_mtlsRootUrl() {
   }
 
   @Test
-  public void testParseServiceName_nonMtlsRootUrl() {
+  public void testParseServiceName_nonGDURootUrl() {
+    AbstractGoogleClient.Builder clientBuilder =
+        new MockGoogleClient.Builder(
+                TRANSPORT, "https://test.random.com/", "", JSON_OBJECT_PARSER, null)
+            .setApplicationName("Test Application");
+    assertNull(clientBuilder.getServiceName());
+  }
+
+  @Test
+  public void testIsUserSetEndpoint_nonMtlsRootUrl() {
     AbstractGoogleClient.Builder clientBuilder =
         new MockGoogleClient.Builder(
                 TRANSPORT, "https://random.googleapis.com/", "", JSON_OBJECT_PARSER, null)
             .setApplicationName("Test Application");
-    assertEquals(clientBuilder.getServiceName(), "random");
+    assertFalse(clientBuilder.isUserConfiguredEndpoint);
   }
 
   @Test
-  public void testParseServiceName_nonGDURootUrl() {
+  public void testIsUserSetEndpoint_mtlsRootUrl() {
+    AbstractGoogleClient.Builder clientBuilder =
+        new MockGoogleClient.Builder(
+                TRANSPORT, "https://test.mtls.googleapis.com/", "", JSON_OBJECT_PARSER, null)
+            .setApplicationName("Test Application");
+    assertFalse(clientBuilder.isUserConfiguredEndpoint);
+  }
+
+  @Test
+  public void testIsUserSetEndpoint_nonGDURootUrl() {
     AbstractGoogleClient.Builder clientBuilder =
         new MockGoogleClient.Builder(
                 TRANSPORT, "https://test.random.com/", "", JSON_OBJECT_PARSER, null)
             .setApplicationName("Test Application");
-    assertNull(clientBuilder.getServiceName());
+    assertTrue(clientBuilder.isUserConfiguredEndpoint);
+  }
+
+  @Test
+  public void testIsUserSetEndpoint_regionalEndpoint() {
+    AbstractGoogleClient.Builder clientBuilder =
+        new MockGoogleClient.Builder(
+                TRANSPORT,
+                "https://us-east-4.coolservice.googleapis.com/",
+                "",
+                JSON_OBJECT_PARSER,
+                null)
+            .setApplicationName("Test Application");
+    assertTrue(clientBuilder.isUserConfiguredEndpoint);
   }
 
   @Test