diff --git a/.gitignore b/.gitignore
index c7c52a9..f7b4cec 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,5 @@
-credentials.json
\ No newline at end of file
+credentials.json
+.venv/
+*.pyc
+__pycache__/
+.env
\ No newline at end of file
diff --git a/app.py b/app.py
index 3f47f55..f5b6961 100644
--- a/app.py
+++ b/app.py
@@ -2,11 +2,31 @@ import os
 import yaml
 import gspread
 import secrets
+import logging
+import sys
 from flask import Flask, render_template, request, redirect, url_for, abort, session
 from datetime import datetime
 
+# Configure logging for Docker/Portainer
+logging.basicConfig(
+    level=logging.INFO,
+    format='%(asctime)s - %(name)s - %(levelname)s - %(message)s',
+    handlers=[logging.StreamHandler(sys.stdout)]
+)
+logger = logging.getLogger(__name__)
+
 app = Flask(__name__)
-app.secret_key = os.environ.get('SECRET_KEY', secrets.token_hex(32))
+
+# Fail-fast secret requirement (allow bypass for pytest testing)
+secret_key = os.environ.get('SECRET_KEY')
+if not secret_key:
+    if os.environ.get('TESTING_NO_APPEND') or 'pytest' in sys.modules:
+        secret_key = 'test_secret_bypassed'
+    else:
+        logger.critical("No SECRET_KEY set! Exiting. Set it in .env or Portainer Stack secrets.")
+        sys.exit(1)
+        
+app.secret_key = secret_key
 
 def generate_csrf_token():
     if '_csrf_token' not in session:
@@ -40,7 +60,7 @@ def get_google_sheet(sheet_id, tab_name=None):
             # Default to first tab
             return sh.sheet1
     except Exception as e:
-        print(f"Error connecting to Google Sheet (ID: {sheet_id}, Tab: {tab_name}): {e}")
+        logger.error(f"Error connecting to Google Sheet (ID: {sheet_id}, Tab: {tab_name}): {e}")
         return None
 
 # NEW: Fetch and filter participants for public display
@@ -82,7 +102,7 @@ def get_public_participants(sheet_id, tab_name=None):
             
         return public_list
     except Exception as e:
-        print(f"Error fetching participants: {e}")
+        logger.error(f"Error fetching participants: {e}")
         return []
 
 @app.route('/')
@@ -146,9 +166,15 @@ def event_form(event_slug):
         sheet = get_google_sheet(sheet_id, tab_name)
         if sheet:
             if not os.environ.get('TESTING_NO_APPEND'):
-                sheet.append_row(form_data)
+                try:
+                    sheet.append_row(form_data)
+                    logger.info(f"Successfully appended registration for {form_data[7]} to {tab_name}")
+                except Exception as e:
+                    logger.error(f"Failed to append row to {tab_name}: {e}")
+                    return f"Error appending data. Try again later."
             return redirect(url_for('success', event_slug=event_slug))
         else:
+            logger.error(f"Could not connect to tab '{tab_name}' during POST.")
             return f"Error: Could not connect to Google Sheet Tab '{tab_name}'. Check server logs."
 
     # GET Request: Fetch participants to show at bottom of form
diff --git a/docker-compose.yaml b/docker-compose.yaml
index 9cc027f..c9c47e2 100644
--- a/docker-compose.yaml
+++ b/docker-compose.yaml
@@ -4,6 +4,8 @@ services:
     build: .
     container_name: sailing_forms
     restart: unless-stopped
+    env_file:
+      - .env
     ports:
       - "5000:5000"  
     volumes:
diff --git a/tests/test_e2e.py b/tests/test_e2e.py
index 747a3b8..e6b483c 100644
--- a/tests/test_e2e.py
+++ b/tests/test_e2e.py
@@ -1,29 +1,37 @@
 import os
 import re
 import pytest
-from playwright.sync_api import Page, expect
+from playwright.sync_api import sync_playwright, expect
 
-def test_homepage_has_title(page: Page):
-    page.goto("http://localhost:5000/")
-    expect(page).to_have_title(re.compile("Zeilwedstrijden"))
+def test_homepage_has_title():
+    with sync_playwright() as p:
+        browser = p.chromium.launch()
+        page = browser.new_page()
+        page.goto("http://localhost:5000/")
+        expect(page).to_have_title(re.compile("Zeilwedstrijden"))
+        browser.close()
 
-def test_submission_flow(page: Page):
-    page.goto("http://localhost:5000/zomeravond")
-    
-    # Fill required fields
-    page.select_option("select[name='klasse']", label="Kajuitklasse")
-    page.fill("input[name='zeilnummer']", "42")
-    page.fill("input[name='bootnaam']", "Vliegende Hollander")
-    page.fill("input[name='naam']", "Hendrik Test")
-    page.fill("input[name='telefoonmobiel']", "0612345678")
-    page.fill("input[name='email']", "hendrik@example.com")
-    
-    # Accept terms
-    page.check("input#terms")
-    
-    # Submit
-    page.click("button[type='submit']")
-    
-    # Expect success redirect
-    expect(page).to_have_url(re.compile(r".*/zomeravond/success"))
-    expect(page.locator("h1")).to_have_text("Bedankt!")
+def test_submission_flow():
+    with sync_playwright() as p:
+        browser = p.chromium.launch()
+        page = browser.new_page()
+        page.goto("http://localhost:5000/zomeravond")
+        
+        # Fill required fields
+        page.select_option("select[name='klasse']", label="Kajuitklasse")
+        page.fill("input[name='zeilnummer']", "42")
+        page.fill("input[name='bootnaam']", "Vliegende Hollander")
+        page.fill("input[name='naam']", "Hendrik Test")
+        page.fill("input[name='telefoonmobiel']", "0612345678")
+        page.fill("input[name='email']", "hendrik@example.com")
+        
+        # Accept terms
+        page.check("input#terms")
+        
+        # Submit
+        page.click("button[type='submit']")
+        
+        # Expect success redirect
+        expect(page).to_have_url(re.compile(r".*/zomeravond/success"))
+        expect(page.locator("h1")).to_have_text("Bedankt!")
+        browser.close()