Azure Functions Overview

Azure Functions is a solution for easily running small pieces of code, or "functions," in the cloud. You can write just the code you need for the problem at hand, without worrying about a whole application or the infrastructure to run it. Functions can make development even more productive, and you can use your development language of choice, such as C#, F#, Node.js, Python or PHP. Pay only for the time your code runs and trust Azure to scale as needed.

This topic provides a high-level overview of Azure Functions. If you want to jump right in and get started with Azure Functions, start with Create your first Azure Function. If you are looking for more technical information about Functions, see the developer reference.

Features

Here are some key features of Azure Functions:

  • Choice of language - Write functions using C#, F#, Node.js, Python, PHP, batch, bash, or any executable.
  • Pay-per-use pricing model - Pay only for the time spent running your code. See the Consumption hosting plan option in the pricing section.
  • Bring your own dependencies - Functions supports NuGet and NPM, so you can use your favorite libraries.
  • Integrated security - Protect HTTP-triggered functions with OAuth providers such as Azure Active Directory, Facebook, Google, Twitter, and Microsoft Account.
  • Simplified integration - Easily leverage Azure services and software-as-a-service (SaaS) offerings. See the integrations section for some examples.
  • Flexible development - Code your functions right in the portal or set up continuous integration and deploy your code through GitHub, Visual Studio Team Services, and other supported development tools.
  • Open-source - The Functions runtime is open-source and available on GitHub.

What can I do with Functions?

Azure Functions is a great solution for processing data, integrating systems, working with the internet-of-things (IoT), and building simple APIs and microservices. Consider Functions for tasks like image or order processing, file maintenance, long-running tasks that you want to run in a background thread, or for any tasks that you want to run on a schedule.

Functions provides templates to get you started with key scenarios, including the following:

  • BlobTrigger - Process Azure Storage blobs when they are added to containers. You might use this function for image resizing.
  • EventHubTrigger - Respond to events delivered to an Azure Event Hub. Particularly useful in application instrumentation, user experience or workflow processing, and Internet of Things (IoT) scenarios.
  • Generic webhook - Process webhook HTTP requests from any service that supports webhooks.
  • GitHub webhook - Respond to events that occur in your GitHub repositories. For an example, see Create a webhook or API function.
  • HTTPTrigger - Trigger the execution of your code by using an HTTP request.
  • QueueTrigger - Respond to messages as they arrive in an Azure Storage queue. For an example, see Create an Azure Function that binds to an Azure service.
  • ServiceBusQueueTrigger - Connect your code to other Azure services or on-premise services by listening to message queues.
  • ServiceBusTopicTrigger - Connect your code to other Azure services or on-premise services by subscribing to topics.
  • TimerTrigger - Execute cleanup or other batch tasks on a predefined schedule. For an example, see Create an event processing function.

Azure Functions supports triggers, which are ways to start execution of your code, and bindings, which are ways to simplifying coding for input and output data. For a detailed description of the triggers and bindings that Azure Functions provides, see Azure Functions triggers and bindings developer reference.

Integrations

Azure Functions integrates with various Azure and 3rd-party services. These services can trigger your function and start execution, or they can serve as input and output for your code. The following service integrations are supported by Azure Functions.

  • Azure DocumentDB
  • Azure Event Hubs
  • Azure Mobile Apps (tables)
  • Azure Notification Hubs
  • Azure Service Bus (queues and topics)
  • Azure Storage (blob, queues, and tables)
  • GitHub (webhooks)
  • On-premises (using Service Bus)

How much does Functions cost?

Azure Functions has two kinds of pricing plans, choose the one that best fits your needs:

  • Consumption plan - When your function runs, Azure provides all of the necessary computational resources. You don't have to worry about resource management, and you only pay for the time that your code runs.
  • App Service plan - Run your functions just like your web, mobile, and API apps. When you are already using App Service for your other applications, you can run your functions on the same plan at no additional cost.

Full pricing details are available on the Functions Pricing page. For more information about scaling your functions, see How to scale Azure Functions.

Next Steps