Designing Highly Available and Scalable Web Applications Using Azure App Services and Azure Functions

Web applications today must be able to support and serve users around the world without any interruptions. This paper describes a way to design architecture by using Azure App Services and Azure Functions to satisfy these demands. We outline the goals and approaches for developing web applications on the cloud that can deal with sudden application stops. It is clear from our study that using Azure’s functionality, like load balancing, auto-scaling and multi-zone deployment, leads to almost continuous uptime and helps cope with any sudden increase in traffic. We use Azure App Service for the front end and Azure Functions based on Python for the back end, setting up everything using Terraform as code. They reveal that scaling horizontally results in much better throughput than scaling vertically. We discuss the high availability services such as Azure’s 99.95% SLA guarantees, Traffic Manager and Front Door. The comparison table makes it clear that using App Service all the time is more expensive than using Azure Functions only when needed. Steps for identity management using Azure AD (Entra ID), secure storage of secrets in Key Vault and a safe DevOps process are recommended. The concepts are demonstrated with a live case study of the Contoso retail app. To sum up, the paper points out that using both Azure App Services and Functions in combination enables web applications to be highly scalable, always available, safe, cost-efficient and in line with today’s best cloud-based practices for enterprises.