diff --git a/.env.example b/.env.example
new file mode 100644
index 0000000..a8e59fc
--- /dev/null
+++ b/.env.example
@@ -0,0 +1,10 @@
+# Project / DB names used by both emulator bootstrap and your Go app
+SPANNER_PROJECT=test-project
+SPANNER_INSTANCE=testinstance
+SPANNER_DATABASE=testdb
+
+# When your Go app runs on the HOST (Mac/Windows/Linux):
+SPANNER_EMULATOR_HOST=localhost:9010
+
+# When your Go app runs INSIDE docker-compose:
+SPANNER_EMULATOR_HOST_DOCKER=spanner:9010
diff --git a/.env.sample b/.env.sample
deleted file mode 100644
index e69de29..0000000