diff --git a/etl/config.py b/etl/config.py
index 4cd53b2060b..ff33c0213af 100644
--- a/etl/config.py
+++ b/etl/config.py
@@ -589,3 +589,14 @@ def read_sqls(self, sql: List[str], *args, **kwargs) -> List[pd.DataFrame]:
         DB_HOST=DB_HOST,
     )
 )
+
+
+# Validate config
+def no_trailing_slash(url: str | None) -> None:
+    if url is not None and url.endswith("/"):
+        raise ValueError(f"Env {url} should not have a trailing slash.")
+
+
+env_vars = [ADMIN_HOST, TAILSCALE_ADMIN_HOST, DATA_API_URL, BAKED_VARIABLES_PATH, R2_SNAPSHOTS_PUBLIC_READ]
+for env_var in env_vars:
+    no_trailing_slash(env_var)