Azure API App Overview

An Azure API App is a fully managed Platform-as-a-Service (PaaS) feature within Azure App Service that’s designed specifically for building, hosting, and consuming RESTful APIs in the cloud — with enterprise-grade security, scalability, and integration options.

Think of it as a specialized hosting environment for APIs that gives you all the benefits of Azure App Service (like scaling, deployment slots, and language flexibility) but with API-centric features baked in.

Key Capabilities

• Multi-language support – Host APIs built in .NET, .NET Core, Java, PHP, Python, or Node.js without changing your code.
• Swagger/OpenAPI integration – Automatically generate interactive API documentation and client SDKs in multiple languages.
• Built-in authentication & authorization – Secure APIs with Azure Active Directory, OAuth, or social logins without writing extra auth code.
• CORS configuration – Enable cross-origin requests easily for web and mobile clients.
• Hybrid connectivity – Connect securely to on-premises systems or private networks.
• Deployment slots – Test new API versions in staging before swapping to production with zero downtime.
• Integration with Azure services – Works seamlessly with Logic Apps, API Management, and CI/CD pipelines.

Why Use Azure API Apps?

• Faster API delivery – Deploy existing APIs “as-is” without re-architecting.
• Enterprise security – Identity provider integration and role-based access control.
• Scalability – Manual or auto-scaling based on demand.
• Developer productivity – Visual Studio integration for building, debugging, and publishing APIs.

Typical Use Cases

• Hosting microservices APIs for web/mobile apps.
• Exposing internal systems securely to partners or customers.
• Creating APIs that integrate with Azure Logic Apps for automation workflows.
• Providing a documented API for third-party developers via Swagger UI.

Azure API App vs Azure Web App

Here’s a side-by-side comparison of Azure API Apps and Azure Web Apps so you can quickly see when each makes the most sense.

Feature / Aspect	Azure API App	Azure Web App
Primary Purpose	Hosting and exposing RESTful APIs with API-centric features like Swagger/OpenAPI integration, CORS, and built-in authentication.	Hosting websites, web applications, and server-rendered front-ends.
Optimized For	API endpoints, microservices, and backend services consumed by web, mobile, or partner apps.	HTML/CSS/JS front-ends, CMS platforms, and full-stack web apps.
Built-in API Features	API definition & metadata (Swagger), client SDK generation, API-level security, easy CORS setup.	No API-specific tooling by default, but can still host APIs if you add them manually.
Authentication & Authorization	Integrated with Azure AD, OAuth, social logins; can secure endpoints without extra code.	Same authentication options available, but not pre-emphasized for API-only scenarios.
Integration	Designed to work seamlessly with Azure API Management, Logic Apps, and hybrid connections.	Integrates with Azure services, but API Management integration is optional.
Deployment	Same deployment methods as Web Apps (Git, Azure DevOps, GitHub, ZIP deploy, etc.).	Same deployment methods; supports staging slots, CI/CD, and global scaling.
Scalability	Auto-scale based on API traffic; ideal for high-volume API calls.	Auto-scale based on web traffic; ideal for high-volume site visits.
Typical Use Cases	Public/partner APIs, backend services for mobile/web apps, microservices.	Marketing sites, e-commerce platforms, CMS (WordPress, Drupal), full-stack apps.
Overlap	Can host web apps if needed, but optimized for API delivery.	Can host APIs if needed, but optimized for web content delivery.

Key takeaway: Both are part of Azure App Service and share the same underlying infrastructure. The main difference is focus — API Apps come with API-friendly features out of the box, while Web Apps are geared toward serving web pages and front-end experiences. In modern Azure, you can technically host either in a single App Service plan, but choosing the right template speeds up setup and aligns defaults with your workload.

Azure App Service Decision Flow

Start Here

What are you deploying?

• If it's a RESTful API or microservice backend → Go to Step A
• If it's a website or front-end app → Go to Step B

Step A: API App Path

• Do you need Swagger/OpenAPI integration? → Yes → Use Azure API App
• Do you need built-in authentication (AAD, OAuth)? → Yes → Use Azure API App
• Do you plan to expose endpoints to Logic Apps or API Management? → Yes → Use Azure API App
• Otherwise → Azure Web App may still work, but API App is optimized

Step B: Web App Path

• Is your app serving HTML/CSS/JS or using server-side rendering? → Yes → Use Azure Web App
• Is it a CMS (WordPress, Drupal) or a full-stack site? → Yes → Use Azure Web App
• Do you need deployment slots, CI/CD, or scaling? → Yes → Both options support this
• Do you need API endpoints but no Swagger/auth integration? → Web App is sufficient

Final Tip

Pro Tip: Both API App and Web App run on the same App Service infrastructure. Choose based on feature alignment, not just naming.