--- a/src/pyload/core/__init__.py
+++ b/src/pyload/core/__init__.py
@@ -130,6 +130,14 @@ class Core:
         else:
             self._debug = max(0, int(debug))
 
+        # Process core config environment variables (NixOS declarative config)
+        for env, value in os.environ.items():
+            if not env.startswith("PYLOAD__"):
+                continue
+            parts = env.removeprefix("PYLOAD__").lower().split("__", 1)
+            if len(parts) == 2 and parts[0] in self.config.config:
+                self.config.set(parts[0], parts[1], value)
+
         # If no argument set, read storage dir from config file,
         # otherwise save setting to config dir
         if storagedir is None:
@@ -226,6 +234,20 @@ class Core:
         self.acm = self.account_manager = AccountManager(self)
         self.thm = self.thread_manager = ThreadManager(self)
         self.cpm = self.captcha_manager = CaptchaManager(self)
+
+        # Process plugin config environment variables BEFORE AddonManager (NixOS declarative config)
+        # This must happen before AddonManager reads the enabled flag to decide which addons to start
+        # Build case-insensitive lookup map for plugin names
+        plugin_name_map = {name.lower(): name for name in self.config.plugin.keys()}
+
+        for env, value in os.environ.items():
+            if not env.startswith("PYLOAD__"):
+                continue
+            parts = env.removeprefix("PYLOAD__").lower().split("__", 1)
+            if len(parts) == 2 and parts[0] in plugin_name_map:
+                actual_plugin_name = plugin_name_map[parts[0]]
+                self.config.set_plugin(actual_plugin_name, parts[1], value)
+
         self.adm = self.addon_manager = AddonManager(self)
 
     def _setup_permissions(self):