diff --git a/visual_regression_tracker/visualRegressionTracker.py b/visual_regression_tracker/visualRegressionTracker.py
index 0679506..f847033 100644
--- a/visual_regression_tracker/visualRegressionTracker.py
+++ b/visual_regression_tracker/visualRegressionTracker.py
@@ -3,6 +3,8 @@
 
 import requests
 
+from urllib.parse import urljoin
+
 from .types import \
     Build, TestRun, TestRunResponse, TestRunStatus, \
     _to_dict, _from_dict, TestRunResult
@@ -37,7 +39,7 @@ def start(self):
             'project': self.config.project,
         }
         result = _http_request(
-            f'{self.config.apiUrl}/builds',
+            urljoin(self.config.apiUrl,'/builds'),
             'post',
             data,
             self.headers