diff --git a/ipinfo/handler_utils.py b/ipinfo/handler_utils.py
index 72f9b14..d81a126 100644
--- a/ipinfo/handler_utils.py
+++ b/ipinfo/handler_utils.py
@@ -9,7 +9,7 @@
 from .version import SDK_VERSION
 
 # Base URL to make requests against.
-API_URL = "https://ipinfo.io"
+API_URL = os.environ.get("IPINFO_API_URL", "https://ipinfo.io")
 
 # Used to transform incoming responses with country abbreviations into the full
 # expanded country name, e.g. "PK" -> "Pakistan".