diff --git a/requirements-dev.lock b/requirements-dev.lock
index 3f30eeb..a01488a 100644
--- a/requirements-dev.lock
+++ b/requirements-dev.lock
@@ -10,7 +10,7 @@
 altgraph==0.17.4
 astroid==3.1.0
 background==0.2.1
-black==24.2.0
+black==24.3.0
 blinker==1.7.0
 certifi==2024.2.2
 charset-normalizer==3.3.2
@@ -20,34 +20,34 @@ coveralls==3.3.1
 dill==0.3.8
 docopt==0.6.2
 exceptiongroup==1.2.0
-flask==3.0.2
-idna==3.6
+flask==3.0.3
+idna==3.7
 iniconfig==2.0.0
 isort==5.13.2
 itsdangerous==2.1.2
 jinja2==3.1.3
-markdown==3.5.2
+markdown==3.6
 markupsafe==2.1.5
 mccabe==0.7.0
-mypy==1.8.0
+mypy==1.9.0
 mypy-extensions==1.0.0
-packaging==23.2
+packaging==24.0
 pathspec==0.12.1
 platformdirs==4.2.0
 pluggy==1.4.0
 pydal==20231114.3
-pyinstaller==6.4.0
-pyinstaller-hooks-contrib==2024.1
+pyinstaller==6.5.0
+pyinstaller-hooks-contrib==2024.3
 pylint==3.1.0
 pyrss2gen==1.1
-pytest==8.0.2
-pytest-cov==4.1.0
+pytest==8.1.1
+pytest-cov==5.0.0
 requests==2.31.0
 tomli==2.0.1
 tomlkit==0.12.4
-types-markdown==3.5.0.20240129
-typing-extensions==4.10.0
+types-markdown==3.6.0.20240316
+typing-extensions==4.11.0
 urllib3==2.2.1
-werkzeug==3.0.1
+werkzeug==3.0.2
 # The following packages are considered to be unsafe in a requirements file:
-setuptools==69.1.1
+setuptools==69.3.0
diff --git a/requirements.lock b/requirements.lock
index edc27ec..fca2376 100644
--- a/requirements.lock
+++ b/requirements.lock
@@ -12,15 +12,15 @@ blinker==1.7.0
 certifi==2024.2.2
 charset-normalizer==3.3.2
 click==8.1.7
-flask==3.0.2
-idna==3.6
+flask==3.0.3
+idna==3.7
 itsdangerous==2.1.2
 jinja2==3.1.3
-markdown==3.5.2
+markdown==3.6
 markupsafe==2.1.5
 pydal==20231114.3
 pyrss2gen==1.1
 requests==2.31.0
-types-markdown==3.5.0.20240129
+types-markdown==3.6.0.20240316
 urllib3==2.2.1
-werkzeug==3.0.1
+werkzeug==3.0.2
diff --git a/src/stacosys/interface/__init__.py b/src/stacosys/interface/__init__.py
index d72483d..fb1fbd1 100644
--- a/src/stacosys/interface/__init__.py
+++ b/src/stacosys/interface/__init__.py
@@ -7,7 +7,6 @@ import background
 from flask import Flask
 
 from stacosys.db import dao
-from stacosys.service import config, mailer
 from stacosys.service.configuration import ConfigParameter
 
 app = Flask(__name__)
@@ -20,7 +19,7 @@ logger = logging.getLogger(__name__)
 
 @background.task
 def submit_new_comment(comment):
-    site_url = config.get(ConfigParameter.SITE_URL)
+    site_url = app.config["CONFIG"].get(ConfigParameter.SITE_URL)
     comment_list = (
         f"Web admin interface: {site_url}/web/admin",
         "",
@@ -35,9 +34,9 @@ def submit_new_comment(comment):
     email_body = "\n".join(comment_list)
 
     # send email to notify admin
-    site_name = config.get(ConfigParameter.SITE_NAME)
+    site_name = app.config["CONFIG"].get(ConfigParameter.SITE_NAME)
     subject = f"STACOSYS {site_name}"
-    if mailer.send(subject, email_body):
+    if app.config["MAILER"].send(subject, email_body):
         logger.debug("new comment processed")
         # save notification datetime
         dao.notify_comment(comment)
diff --git a/src/stacosys/interface/form.py b/src/stacosys/interface/form.py
index 8513438..11d2ca3 100644
--- a/src/stacosys/interface/form.py
+++ b/src/stacosys/interface/form.py
@@ -6,7 +6,6 @@ from flask import abort, redirect, request
 
 from stacosys.db import dao
 from stacosys.interface import app, submit_new_comment
-from stacosys.service import config
 from stacosys.service.configuration import ConfigParameter
 
 logger = logging.getLogger(__name__)
@@ -47,7 +46,7 @@ def new_form_comment():
     # send notification e-mail asynchronously
     submit_new_comment(comment)
 
-    return redirect(config.get(ConfigParameter.SITE_REDIRECT), code=302)
+    return redirect(app.config["CONFIG"].get(ConfigParameter.SITE_REDIRECT), code=302)
 
 
 def check_form_data(posted_comment):
diff --git a/src/stacosys/interface/web/admin.py b/src/stacosys/interface/web/admin.py
index 8d81e3c..64aa3da 100644
--- a/src/stacosys/interface/web/admin.py
+++ b/src/stacosys/interface/web/admin.py
@@ -8,7 +8,6 @@ from flask import flash, redirect, render_template, request, session
 
 from stacosys.db import dao
 from stacosys.interface import app
-from stacosys.service import config, rss
 from stacosys.service.configuration import ConfigParameter
 
 logger = logging.getLogger(__name__)
@@ -25,8 +24,8 @@ def index():
 def is_login_ok(username, password):
     hashed = hashlib.sha256(password.encode()).hexdigest().upper()
     return (
-        config.get(ConfigParameter.WEB_USERNAME) == username
-        and config.get(ConfigParameter.WEB_PASSWORD) == hashed
+        app.config["CONFIG"].get(ConfigParameter.WEB_USERNAME) == username
+        and app.config["CONFIG"].get(ConfigParameter.WEB_PASSWORD) == hashed
     )
 
 
@@ -42,7 +41,9 @@ def login():
         flash("Identifiant ou mot de passe incorrect")
         return redirect("/web/login")
     # GET
-    return render_template("login_" + config.get(ConfigParameter.LANG) + ".html")
+    return render_template(
+        "login_" + app.config["CONFIG"].get(ConfigParameter.LANG) + ".html"
+    )
 
 
 @app.route("/web/logout", methods=["GET"])
@@ -55,7 +56,7 @@ def logout():
 def admin_homepage():
     if not (
         "user" in session
-        and session["user"] == config.get(ConfigParameter.WEB_USERNAME)
+        and session["user"] == app.config["CONFIG"].get(ConfigParameter.WEB_USERNAME)
     ):
         # TODO localization
         flash("Vous avez été déconnecté.")
@@ -63,9 +64,9 @@ def admin_homepage():
 
     comments = dao.find_not_published_comments()
     return render_template(
-        "admin_" + config.get(ConfigParameter.LANG) + ".html",
+        "admin_" + app.config["CONFIG"].get(ConfigParameter.LANG) + ".html",
         comments=comments,
-        baseurl=config.get(ConfigParameter.SITE_URL),
+        baseurl=app.config["CONFIG"].get(ConfigParameter.SITE_URL),
     )
 
 
@@ -77,7 +78,7 @@ def admin_action():
         flash("Commentaire introuvable")
     elif request.form.get("action") == "APPROVE":
         dao.publish_comment(comment)
-        rss.generate()
+        app.config["RSS"].generate()
         # TODO localization
         flash("Commentaire publié")
     else:
diff --git a/src/stacosys/run.py b/src/stacosys/run.py
index eb90a09..5634764 100644
--- a/src/stacosys/run.py
+++ b/src/stacosys/run.py
@@ -9,46 +9,51 @@ import sys
 from stacosys.db import database
 from stacosys.interface import api, app, form
 from stacosys.interface.web import admin
-from stacosys.service import config, mailer, rss
-from stacosys.service.configuration import ConfigParameter
+from stacosys.service.configuration import Config, ConfigParameter
+from stacosys.service.mail import Mailer
+from stacosys.service.rssfeed import Rss
 
 
 # configure logging
-def configure_logging(level):
-    root_logger = logging.getLogger()
-    root_logger.setLevel(level)
-    handler = logging.StreamHandler()
-    handler.setLevel(level)
-    formatter = logging.Formatter("[%(asctime)s] %(name)s %(levelname)s %(message)s")
-    handler.setFormatter(formatter)
-    root_logger.addHandler(handler)
-
-
-def stacosys_server(config_pathname):
-    # configure logging
+def configure_logging() -> logging.Logger:
+    logging.basicConfig(
+        level=logging.INFO, format="[%(asctime)s] %(name)s %(levelname)s %(message)s"
+    )
     logger = logging.getLogger(__name__)
-    configure_logging(logging.INFO)
     logging.getLogger("werkzeug").level = logging.WARNING
+    return logger
+
 
-    # check config file exists
+def load_and_validate_config(config_pathname: str, logger: logging.Logger) -> Config:
     if not os.path.isfile(config_pathname):
         logger.error("Configuration file '%s' not found.", config_pathname)
-        sys.exit(1)
+        raise FileNotFoundError(f"Configuration file '{config_pathname}' not found.")
 
-    # load and check config
+    config = Config()
     config.load(config_pathname)
-    is_config_ok, erreur_config = config.check()
-    if not is_config_ok:
-        logger.error("Configuration incorrecte '%s'", erreur_config)
-        sys.exit(1)
-    logger.info(config)
+    if not config.check():
+        raise ValueError(f"Invalid configuration '{config_pathname}'")
+    logger.info("Configuration loaded successfully.")
+    return config
 
-    # initialize database
-    database.configure(config.get(ConfigParameter.DB))
 
-    logger.info("Start Stacosys application")
+def configure_and_validate_mailer(config, logger):
+    mailer = Mailer()
+    mailer.configure_smtp(
+        config.get(ConfigParameter.SMTP_HOST),
+        config.get_int(ConfigParameter.SMTP_PORT),
+        config.get(ConfigParameter.SMTP_LOGIN),
+        config.get(ConfigParameter.SMTP_PASSWORD),
+    )
+    mailer.configure_destination(config.get(ConfigParameter.SITE_ADMIN_EMAIL))
+    if not mailer.check():
+        logger.error("Email configuration not working")
+        sys.exit(1)
+    return mailer
 
-    # generate RSS
+
+def configure_rss(config):
+    rss = Rss()
     rss.configure(
         config.get(ConfigParameter.RSS_FILE),
         config.get(ConfigParameter.SITE_NAME),
@@ -56,20 +61,22 @@ def stacosys_server(config_pathname):
         config.get(ConfigParameter.SITE_URL),
     )
     rss.generate()
+    return rss
 
-    # configure mailer
-    mailer.configure_smtp(
-        config.get(ConfigParameter.SMTP_HOST),
-        config.get_int(ConfigParameter.SMTP_PORT),
-        config.get(ConfigParameter.SMTP_LOGIN),
-        config.get(ConfigParameter.SMTP_PASSWORD),
-    )
-    mailer.configure_destination(config.get(ConfigParameter.SITE_ADMIN_EMAIL))
-    mailer.check()
 
-    logger.info("start interfaces %s %s %s", api, form, admin)
+def main(config_pathname):
+    logger = configure_logging()
+    config = load_and_validate_config(config_pathname, logger)
+    database.configure(config.get(ConfigParameter.DB))
 
-    # start Flask
+    logger.info("Start Stacosys application")
+    rss = configure_rss(config)
+    mailer = configure_and_validate_mailer(config, logger)
+
+    logger.info("start interfaces %s %s %s", api, form, admin)
+    app.config["CONFIG"] = config
+    app.config["MAILER"] = mailer
+    app.config["RSS"] = rss
     app.run(
         host=config.get(ConfigParameter.HTTP_HOST),
         port=config.get_int(ConfigParameter.HTTP_PORT),
@@ -82,4 +89,8 @@ if __name__ == "__main__":
     parser = argparse.ArgumentParser()
     parser.add_argument("config", help="config path name")
     args = parser.parse_args()
-    stacosys_server(args.config)
+    try:
+        main(args.config)
+    except Exception as e:
+        logging.error(f"Failed to start application: {e}")
+        sys.exit(1)
diff --git a/src/stacosys/service/__init__.py b/src/stacosys/service/__init__.py
deleted file mode 100644
index 6fcc80a..0000000
--- a/src/stacosys/service/__init__.py
+++ /dev/null
@@ -1,10 +0,0 @@
-#!/usr/bin/env python
-# -*- coding: utf-8 -*-
-
-from .configuration import Config
-from .mail import Mailer
-from .rssfeed import Rss
-
-config = Config()
-mailer = Mailer()
-rss = Rss()
diff --git a/src/stacosys/service/mail.py b/src/stacosys/service/mail.py
index d7fe5ca..4e52228 100644
--- a/src/stacosys/service/mail.py
+++ b/src/stacosys/service/mail.py
@@ -2,44 +2,41 @@
 # -*- coding: utf-8 -*-
 
 import logging
-import smtplib
-import ssl
 from email.mime.text import MIMEText
+from smtplib import SMTP_SSL, SMTPAuthenticationError
 
 logger = logging.getLogger(__name__)
 
 
 class Mailer:
     def __init__(self) -> None:
-        self._smtp_host: str = ""
-        self._smtp_port: int = 0
-        self._smtp_login: str = ""
-        self._smtp_password: str = ""
-        self._site_admin_email: str = ""
+        self._smtp_host = ""
+        self._smtp_port = 0
+        self._smtp_login = ""
+        self._smtp_password = ""
+        self._site_admin_email = ""
 
     def configure_smtp(
-        self,
-        smtp_host,
-        smtp_port,
-        smtp_login,
-        smtp_password,
+        self, smtp_host: str, smtp_port: int, smtp_login: str, smtp_password: str
     ) -> None:
         self._smtp_host = smtp_host
         self._smtp_port = smtp_port
         self._smtp_login = smtp_login
         self._smtp_password = smtp_password
 
-    def configure_destination(self, site_admin_email) -> None:
+    def configure_destination(self, site_admin_email: str) -> None:
         self._site_admin_email = site_admin_email
 
-    def check(self):
-        server = smtplib.SMTP_SSL(
-            self._smtp_host, self._smtp_port, context=ssl.create_default_context()
-        )
-        server.login(self._smtp_login, self._smtp_password)
-        server.close()
-
-    def send(self, subject, message) -> bool:
+    def check(self) -> bool:
+        try:
+            with SMTP_SSL(self._smtp_host, self._smtp_port) as server:
+                server.login(self._smtp_login, self._smtp_password)
+            return True
+        except SMTPAuthenticationError:
+            logger.exception("Invalid credentials")
+            return False
+
+    def send(self, subject: str, message: str) -> bool:
         sender = self._smtp_login
         receivers = [self._site_admin_email]
 
@@ -48,15 +45,14 @@ class Mailer:
         msg["To"] = self._site_admin_email
         msg["From"] = sender
 
-        # pylint: disable=bare-except
         try:
-            server = smtplib.SMTP_SSL(
-                self._smtp_host, self._smtp_port, context=ssl.create_default_context()
-            )
-            server.login(self._smtp_login, self._smtp_password)
-            server.send_message(msg, sender, receivers)
-            server.close()
-            success = True
-        except:
-            success = False
-        return success
+            with SMTP_SSL(self._smtp_host, self._smtp_port) as server:
+                server.login(self._smtp_login, self._smtp_password)
+                server.send_message(msg, sender, receivers)
+            return True
+        except SMTPAuthenticationError:
+            logger.exception("Invalid credentials")
+            return False
+        except Exception as e:
+            logger.exception(f"Error sending email: {e}")
+            return False
diff --git a/tests/test_config.py b/tests/test_config.py
index 057f052..78a2da4 100644
--- a/tests/test_config.py
+++ b/tests/test_config.py
@@ -3,13 +3,14 @@
 
 import pytest
 
-from stacosys.service import config
-from stacosys.service.configuration import ConfigParameter
+from stacosys.service.configuration import Config, ConfigParameter
 
 EXPECTED_DB = "sqlite://db.sqlite"
 EXPECTED_HTTP_PORT = 8080
 EXPECTED_LANG = "fr"
 
+config = Config()
+
 
 @pytest.fixture
 def init_config():
diff --git a/tests/test_form.py b/tests/test_form.py
index d27b89e..f87a172 100644
--- a/tests/test_form.py
+++ b/tests/test_form.py
@@ -7,6 +7,9 @@ import pytest
 
 from stacosys.db import database
 from stacosys.interface import app, form
+from stacosys.service.configuration import Config
+from stacosys.service.mail import Mailer
+from stacosys.service.rssfeed import Rss
 
 
 @pytest.fixture
@@ -14,6 +17,9 @@ def client():
     logger = logging.getLogger(__name__)
     database.configure("sqlite:memory://db.sqlite")
     logger.info(f"start interface {form}")
+    app.config["CONFIG"] = Config()
+    app.config["MAILER"] = Mailer()
+    app.config["RSS"] = Rss()
     return app.test_client()
 
 
diff --git a/tests/test_mail.py b/tests/test_mail.py
index 992845f..69aa307 100644
--- a/tests/test_mail.py
+++ b/tests/test_mail.py
@@ -3,10 +3,11 @@
 
 import pytest
 
-from stacosys.service import mailer
+from stacosys.service.mail import Mailer
 
 
 def test_configure_and_check():
+    mailer = Mailer()
     mailer.configure_smtp("localhost", 2525, "admin", "admin")
     mailer.configure_destination("admin@mydomain.com")
     with pytest.raises(ConnectionRefusedError):
diff --git a/tests/test_rssfeed.py b/tests/test_rssfeed.py
index e2a15b9..5b102fe 100644
--- a/tests/test_rssfeed.py
+++ b/tests/test_rssfeed.py
@@ -1,8 +1,9 @@
 #!/usr/bin/env python
 # -*- coding: UTF-8 -*-
 
-from stacosys.service import rss
+from stacosys.service.rssfeed import Rss
 
 
 def test_configure():
+    rss = Rss()
     rss.configure("comments.xml", "blog", "http", "blog.mydomain.com")