diff --git a/src/wce_crm/__init__.py b/src/wce_crm/__init__.py
index f44e039..c6fce6b 100644
--- a/src/wce_crm/__init__.py
+++ b/src/wce_crm/__init__.py
@@ -1,6 +1,10 @@
 import os
 import sys
 
+import dotenv
+
 if sys.stdout is None or sys.stderr is None:
     sys.stdout = open(os.devnull, "w")
     sys.stderr = open(os.devnull, "w")
+
+dotenv.load_dotenv()
diff --git a/src/wce_crm/constants.py b/src/wce_crm/constants.py
index e8b1b6d..8df5466 100644
--- a/src/wce_crm/constants.py
+++ b/src/wce_crm/constants.py
@@ -4,19 +4,11 @@ import os
 from pathlib import Path
 from typing import Final
 
-import dotenv
 from dopt_basics import io as io_
 
-dotenv.load_dotenv()
-
 # PROJECT_ROOT = Path(__file__).resolve().parents[2]
 LIB_PATH: Final[Path] = Path(__file__).resolve().parent
 
-# DEV_DB_PATH = PROJECT_ROOT / "data/db"
-# DEV_DB_KONTAKTLISTE = DEV_DB_PATH / "wce_kontaktliste.db"
-# assert DEV_DB_KONTAKTLISTE.exists()
-# DEV_DB_CRM = DEV_DB_PATH / "wce_crm.db"
-# assert DEV_DB_CRM.exists()
 
 BASE_PATH = io_.search_folder_path(
     LIB_PATH, stop_folder_name=os.getenv("DOPT_STOP_FOLDER_NAME", "python")
@@ -25,10 +17,10 @@ assert BASE_PATH
 
 
 class Config:
-    DB_PATH_CRM = BASE_PATH / os.getenv("DOPT_DB_CRM", "data/db/wce_crm.db")
-    DB_PATH_MAIN = BASE_PATH / os.getenv("DOPT_DB_MAIN", "data/db/wce_grunderfassung.db")
-
-
-# def setup():
-#     os.environ["DOPT_DB_KONTAKTLISTE"] = str(DEV_DB_KONTAKTLISTE)
-#     os.environ["DOPT_DB_CRM"] = str(DEV_DB_CRM)
+    DEVELOPMENT_STATE: bool = bool(os.getenv("DOPT_DEVELOPMENT", "0"))
+    DB_PATH_CRM: Path = BASE_PATH / os.getenv("DOPT_DB_CRM", "data/db/wce_crm.db")
+    DB_PATH_MAIN: Path = BASE_PATH / os.getenv(
+        "DOPT_DB_MAIN", "data/db/wce_grunderfassung.db"
+    )
+    PATH_LOGGING: Path = BASE_PATH / os.getenv("DOPT_PATH_LOGGING", "data/d-opt.log")
+    LOG_FILENAME: str = "dopt.log"
diff --git a/src/wce_crm/logging.py b/src/wce_crm/logging.py
new file mode 100644
index 0000000..5f6e855
--- /dev/null
+++ b/src/wce_crm/logging.py
@@ -0,0 +1,33 @@
+import logging
+
+from dopt_basics.logging import BASE_LOGGER, setup_logging
+
+from wce_crm.constants import Config
+
+enable_stderr: bool = False
+enable_file: bool = True
+
+if Config.DEVELOPMENT_STATE:
+    enable_stderr = True
+    enable_file = False
+
+if not Config.PATH_LOGGING.exists():
+    Config.PATH_LOGGING.mkdir()
+
+setup_logging(
+    enable_stderr=enable_stderr,
+    enable_file=enable_file,
+    logging_dir=Config.PATH_LOGGING,
+    log_filename=Config.LOG_FILENAME,
+)
+logger_base = BASE_LOGGER.getChild("wce_crm")
+
+# ** GUI
+logger_gui = logger_base.getChild("gui")
+logger_gui.setLevel(logging.DEBUG)
+logger_search_widget = logger_gui.getChild("search_widget")
+logger_search_widget.setLevel(logging.DEBUG)
+logger_get_data = logger_gui.getChild("get_data")
+logger_get_data.setLevel(logging.DEBUG)
+logger_auto_form = logger_gui.getChild("get_data_auto_form")
+logger_auto_form.setLevel(logging.DEBUG)