What are Azure Functions?

Azure Functions is a serverless compute service that lets you run small pieces of code, called "functions," without worrying about managing infrastructure. With Azure Functions, you can build applications by running your code in response to triggers (e.g., HTTP requests, timer events, or messages from other Azure services) and by using bindings to connect your functions to other Azure services.

Core Concepts

Triggers and Bindings

Triggers define how a function is invoked. A trigger is a specific type of Azure service that causes a function to run. Examples include an HTTP trigger for webhooks, a timer trigger for scheduled execution, or a queue trigger for processing messages.

Bindings provide a declarative way to connect your function code to other Azure services. Bindings simplify your code by abstracting away the details of the connection, allowing you to focus on your business logic. There are input bindings, output bindings, and trigger bindings.

Example: An HTTP trigger starts a function when an HTTP request is received. An output binding to Azure Cosmos DB writes data to a database.

Runtime

The Azure Functions runtime provides the execution environment for your functions. It handles scaling, security, and resource management. You can choose from various language runtimes, including:

• .NET
• Node.js
• Java
• Python
• PowerShell
• Custom Handlers (for other languages)

Hosting Options

Azure Functions offers flexible hosting plans to suit your needs:

• Consumption Plan: Pay only for the compute time you consume. Scales automatically.
• Premium Plan: Provides pre-warmed instances, VNet connectivity, and no cold starts.
• App Service Plan: Run functions on existing App Service plans for predictable costs and dedicated resources.

Pricing

The Consumption plan offers a generous free grant each month, and you only pay for the executions and compute time used beyond that. Other plans offer different pricing models. For detailed information, refer to the Azure Functions Pricing page.

Ready to Build?

Now that you have an overview of Azure Functions, you can dive deeper into building your first application or explore specific features:

• Complete the Quickstart tutorial.
• Learn about developing functions locally and deploying them.
• Explore the full API reference and service integrations.