Using Azure App Service Application Settings for Connection Strings

When I first started deploying my Flask app, I spent a lot of time making sure I wasn’t exposing sensitive credentials—especially Azure Blob Storage and Application Insights connection strings.

In Post #11, I explained how to use .env files and python-dotenv to keep secrets out of your repo. That method works great for local dev—but here’s something I learned recently:

Azure App Service provides its own secure way to manage app secrets.

✅ Azure Handles Environment Variables Natively

You can go to:

Azure Portal → App Service → Configuration → Application settings

And from there, you can define key-value pairs that act just like environment variables in your Flask app—without needing a .env file at all.

🔐 Why This Is Better for Deployment

• You avoid committing .env to your repo (even accidentally)
• You don’t need load_dotenv() on production servers
• You manage secrets securely through the Azure portal
• Secrets are injected server-side and never exposed in frontend or logs

📦 How I Set It Up

1. Go to your App Service on Azure
2. Click Configuration → Application settings
3. Add your key-value pairs:
   • AZURE_STORAGE_CONNECTION_STRING
   • CONTAINER_NAME
   • APPLICATIONINSIGHTS_CONNECTION_STRING
   • SECRET_KEY
4. Click Save, and Azure will restart the app with the new settings
5. In your Flask app, access them using os.getenv() as usual:

import os

connection_string = os.getenv("AZURE_STORAGE_CONNECTION_STRING")
container = os.getenv("CONTAINER_NAME")
application_insights = os.getenv("APPLICATIONINSIGHTS_CONNECTION_STRING")
secret_key = os.getenv("SECRET_KEY")
      

📌 Quick Tip

If your Flask app needs a secret key, you can also define SECRET_KEY this way and avoid hardcoding it.

🧪 When Should You Use .env vs Azure App Settings?

💬 Final Thoughts

This might feel like a small discovery—but it’s made my app structure cleaner and my deployment process safer. I now let Azure handle all my runtime secrets, and only use .env for local work.

If you’re building Flask apps and deploying on Azure, I highly recommend you take a few minutes to explore Application settings inside App Service—it’s a best practice that makes a real difference.

Have questions about Flask + Azure secrets or need a config template? Let’s connect.