In my previous post Integrate Facebook to Twitter and Dropbox using Azure App Service Logic Apps , different connectors (Facebook, Twitter & Dropbox) have been used in the workflow. All those connectors where listed on the right side of the workflow design. All those connectors are technically API apps that uses a metadata format called Swagger and REST as pluggable interfaces and JSON as the interservice data format. REST is of course a service interface that is structured along the lines of HTTP and HTTPS; JSON is of course a human-readable JavaScript object. Swagger, most popular metadata format, is a specification for documenting REST APIs. API apps in Azure App Service make it easy to develop, publish, manage, and monetize APIs. If you have some capability you want to expose as an API you should deploy it as API App and benefit from scalable RESTful API with enterprise grade security, simple access control, automatic SDK and Access on-premises data using Hybrid Connections. You can bring your API as-is. You can use ASP.NET, Java, PHP, Node.js or Python for your APIs. Your APIs can take advantage of the features of Azure App Service with no changes. The API App host takes care of managing authentication for the app, which saves you the headache of implementing it yourself. Otherwise, you can build your own REST interface on a Web App Service if you wish. You can also connect your apps to popular SaaS platforms. Azure App Service makes it easy to connect to popular SaaS platforms, including Salesforce, Office 365, Twitter, Facebook, Dropbox, and many more. Microsoft has already built a significant amount of API Apps for the preview:

• Social Connectors: Facebook, Yammer, Twitter, Chatter, Twilio
• Enterprise Connectors: Salesforce, SAP, Marketo, QuickBooks, SugarCRM
• App + Data Services: Azure Media Services, Azure Mobile Services, Azure Service Bus, Azure Storage Blog, Azure Storage Table, Azure WebJobs, Box, Dropbox, HDInsight, Microsoft SQL, Mobile App, MongoDb, Office365, OneDrive, Oracle Database, Sharepoint
• Integration: AS2, BizTalk EDIFACT, BizTalk Flat file encoder, BizTalk JSON Encoder, BizTalk Rules, BizTalk Trading Partner, BizTalk Transformation Service, BizTalk X12, BizTalk XML Validator, BizTalk XPath Extractor, Informix Connector, MQ Connector, Wait
• Protocol Connectors: File, FTP, HTTP, POP3, SFTP, SMTP

Watch this Azure Friday video about API Apps  with Scott Hanselman and  Scott Hunter to learn more about how to use it. Scott Hunter shows here how this new service helps developers build and consume Cloud APIs and participate in the API. You can also try creating an API app by referring App Service Documentation, Create an API app in Azure App Service.

Related links

First Look at Azure API Apps and Logic Apps How do I run an API App that it’s not .NET? https://gautambiztalkblog.com/2015/06/18/exploring-and-evaluating-azure-logic-apps/