How to Use Let's Encrypt on Azure Functions | Custom Domain & SSL Setup

Published 06/09/2026

Description

Azure Functions are incredible for serverless logic, but getting a Let's Encrypt SSL certificate working on a custom domain isn't as straightforward as it is with standard App Services. If you've tried to bind a custom domain, you likely realized that the built-in Microsoft certificates only cover the azurewebsites.net hostname. In this video, I walk you through the complete workaround to enable free, auto-renewing SSL certificates on Azure Functions. We will solve the ACME challenge by building a custom HTTP trigger to handle validation requests and configure all the necessary IAM permissions, App Registrations, and SCM settings required for a professional, secure deployment. 0:00 - Introduction 0:11 - Description 2:53 - Initial Configuration 3:55 - Custom Domain Setup 7:31 - Understanding Default Certificates 8:12 - App Registration & Credentials 11:01 - Subscription ID Requirements 11:30 - Azure Function IAM Permissions 13:22 - Reconfiguring the Default API 17:28 - Creating the Let's Encrypt HTTP Trigger 23:57 - Extension Storage Account Setup 25:02 - SCM / Publishing Configuration 25:25 - Installing the Let's Encrypt Extension 26:22 - Configuring the Extension 28:34 - Certificate Overview & Validation 29:23 - Renewal Pitfalls & Troubleshooting 30:09 - Conclusion What you’ll learn: Custom Domain Validation: How to properly prepare your domain for an Azure Function. The ACME Workaround: Building a custom HTTP trigger to serve the /.well-known/acme-challenge/ path. Identity & Access: Setting up App Registrations and configuring IAM permissions on the correct Resource Group. Extension Management: Installing and configuring the Azure Let's Encrypt extension alongside necessary storage accounts. Automated Renewal: How to ensure your certificate stays valid after the 90-day cycle and what common "pains" to avoid. This tutorial is designed for developers, cloud architects, and DevOps engineers who need a production-ready way to secure serverless applications wi