diff --git a/src/atocore/config.py b/src/atocore/config.py
index d4a9530..3b21a15 100644
--- a/src/atocore/config.py
+++ b/src/atocore/config.py
@@ -104,6 +104,21 @@ class Settings(BaseSettings):
 
     @property
     def resolved_project_registry_path(self) -> Path:
+        """Path to the project registry JSON file.
+
+        If ``ATOCORE_PROJECT_REGISTRY_DIR`` env var is set, the registry
+        lives at ``<that dir>/project-registry.json``. Otherwise falls
+        back to the configured ``project_registry_path`` field.
+
+        This lets Docker deployments point at a mounted volume via env
+        var without the ephemeral in-image ``/app/config/`` getting
+        wiped on every rebuild.
+        """
+        import os
+
+        registry_dir = os.environ.get("ATOCORE_PROJECT_REGISTRY_DIR", "").strip()
+        if registry_dir:
+            return Path(registry_dir) / "project-registry.json"
         return self._resolve_path(self.project_registry_path)
 
     @property