{"id":109134,"date":"2016-06-08T03:27:04","date_gmt":"2016-06-08T10:27:04","guid":{"rendered":""},"modified":"2025-06-11T08:18:25","modified_gmt":"2025-06-11T15:18:25","slug":"building-a-custom-api-for-powerapps-using-azure-app-service-web-apps","status":"publish","type":"post","link":"https:\/\/www.microsoft.com\/en-us\/power-platform\/blog\/power-apps\/building-a-custom-api-for-powerapps-using-azure-app-service-web-apps\/","title":{"rendered":"Building a Custom API for PowerApps using Azure App Service Web Apps"},"content":{"rendered":"

\nOne of the most powerful features that PowerApps offers is the ability to extend its capabilities by creating Custom APIs. Custom APIs are normal REST APIs that expose some functionality. Whether you are trying to build some complex logic or connecting to your existing systems, you can simply create a REST API in your favorite platform using any language, describe it using Swagger<\/a> and use it in PowerApps. We support a few authentication mechanisms such as Azure Active Directory and Basic Authentication, and will add others over time.<\/p>\n

The purpose of this blog is to show you how easy it is to build a Custom API using Azure App Service Web Apps and consume it in PowerApps.<\/p>\n

Azure App Service Web Apps<\/a> <\/strong>is a managed compute environment that provides a very powerful platform for building and hosting sites, web applications, APIs and more. It allows developers to use their favorite development tools and programming languages, including C#, Java, Node.js, PHP, Python and more. It has a rich set of advanced features such as continuous delivery support with Git, GitHub, Dropbox, VSTS and others, multiple slots (for scenarios like managing multiple environments, A\/B testing, etc.), on-premise connectivity, SSL, custom domains, FTP, analytics, and much more.<\/p>\n

Did I mention that you can use it for free<\/strong>? App Service will give you 10 free web sites, so go and create your subscription here<\/a>. To develop the API below you can use Visual Studio Community 2015<\/a> or Visual Studio Code<\/a> which both are free for you to use.<\/p>\n

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What we\u2019ll be building<\/h2>\n

In this example, we will build a REST API using ASP.NET Web API in C# that includes an endpoint called HRApi that will return a list of employees. To keep it simple we will keep those records in a list in memory so that we can focus on how to put the API together and not get distracted with the specific technologies for data access.<\/p>\n

At a high level the steps we will follow are:<\/p>\n

    \n
  1. Use Visual Studio to create the REST API<\/li>\n
  2. Deploy the API to Azure App Service<\/li>\n
  3. Register the Custom API to use in PowerApps<\/li>\n
  4. Build a PowerApp that consumes the API<\/li>\n<\/ol>\n

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    Build the Web API using Visual Studio 2015<\/h2>\n

    REST APIs can be created in any platform and any language. In this case we will use ASP.NET Web API<\/a> since it provides a framework that makes it very easy to build REST API\/services. The main class for building ASP.NET Web API services is called ApiController<\/a>.<\/p>\n

    Create the API Controller<\/p>\n

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