Azure App Service

Azure App Service is a fully managed platform-as-a-service (PaaS) for building, deploying, and scaling web applications and APIs. Unlike VMs, you don't manage the underlying infrastructure — Azure handles patching, load balancing, and scaling for you.

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What is Azure App Service?

App Service lets you host web apps, REST APIs, and mobile backends in the language and framework of your choice without managing virtual machines. You deploy your code (or container) and Azure runs it.

Key Features

Feature	Description
Multi-language	.NET, Java, Node.js, Python, PHP, Ruby, Go, and custom containers
Auto-scaling	Scale out (add instances) and scale up (increase instance size)
Built-in CI/CD	Deploy from GitHub, Azure DevOps, Bitbucket, or local Git
Custom domains & SSL	Bring your own domain and manage TLS certificates
Authentication	Built-in auth with Entra ID, Google, Facebook, and other identity providers
VNet integration	Connect to resources in your virtual network
Deployment slots	Zero-downtime deployments with staging environments
Managed certificates	Free TLS certificates for custom domains

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App Service Plans

Every App Service runs inside an App Service Plan, which defines the compute resources:

Tiers

Tier	Features	Use Case
Free (F1)	1 GiB storage, shared compute, 60 min/day CPU	Testing and experimentation
Basic (B1–B3)	Dedicated compute, custom domains, manual scale (up to 3 instances)	Dev/test workloads
Standard (S1–S3)	Auto-scale (up to 10 instances), deployment slots, VNet integration	Production workloads
Premium v3 (P0v3–P3v3)	Zone redundancy, up to 30 instances, enhanced performance	High-traffic production
Isolated v2 (I1v2–I6v2)	Runs in an App Service Environment (ASE) on your dedicated network	Compliance, isolation

Choosing a Plan

• Free/Basic — development, prototyping, and testing
• Standard — production workloads with moderate traffic
• Premium v3 — high-traffic production requiring zone redundancy and performance
• Isolated v2 — workloads requiring network isolation and compliance

# Create an App Service Plan
az appservice plan create \
  --name myAppPlan \
  --resource-group rg-app-demo \
  --sku S1 \
  --is-linux

# Create a web app
az webapp create \
  --resource-group rg-app-demo \
  --plan myAppPlan \
  --name mywebapp2024 \
  --runtime "NODE:20-lts"

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Deployment Methods

Code Deployment

Method	Description
GitHub Actions	CI/CD pipeline triggered on push to a branch
Azure DevOps	Pipelines integrated with the Azure ecosystem
Local Git	Push from a local Git repository directly to App Service
ZIP deploy	Upload a ZIP file of your application
FTP/FTPS	Upload files directly (not recommended for production)

Container Deployment

App Service can run custom Docker containers:

az webapp create \
  --resource-group rg-app-demo \
  --plan myAppPlan \
  --name mycontainerapp \
  --deployment-container-image-name myregistry.azurecr.io/myapp:latest

You can also deploy multi-container applications using Docker Compose.

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Deployment Slots

Deployment slots are live instances of your app with their own hostname. They enable zero-downtime deployments:

How Slots Work

Production slot: mywebapp.azurewebsites.net  (live traffic)
Staging slot:   mywebapp-staging.azurewebsites.net  (testing)

Deployment Workflow