diff --git a/.dockerignore b/.dockerignore
index da9eab3..ae9a188 100644
--- a/.dockerignore
+++ b/.dockerignore
@@ -1,4 +1,5 @@
 .git/
+.env
 source/
 tiles/
 cache/
diff --git a/.env.example b/.env.example
new file mode 100644
index 0000000..3cf4eaf
--- /dev/null
+++ b/.env.example
@@ -0,0 +1,10 @@
+# Optional HTTPS XYZ template used for the base layer and tiles without Arma coverage.
+# Leave blank to return tiles/empty.png for uncovered coordinates.
+CALLBACK_PROVIDER=
+
+# Local HTTP port and build parallelism.
+HTTP_PORT=9000
+GDAL2TILES_PROCESSES=1
+
+# Optional absolute path used by Coolify for the persistent source directory.
+# ARMA_TILES_SOURCE_DIR=/data/arma-tiles/source
diff --git a/.gitignore b/.gitignore
index bbd3fe1..daab452 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,6 +1,7 @@
 # Generated raster layer and transactional build state
 tiles/
 cache/
+.env
 .tiles-staging-*/
 .tiles-work-*/
 .tiles-previous/