Understanding the Different Types of APIs

Do you know what the different types of APIs are? If not, you had better check out the following insightful information.

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If you’re still unsure what an Application Programming Interface is and how it works, you’ll find a fantastic guide on this page. But even if you do know what APIs are, you may be unaware that there are actually four main types of web APIs. Let’s look at those types in more detail.

Open APIs

Open APIs are also known as Public APIs. They are publicly available with minimal restrictions to developers and others. Open APIs focus on external users to access services or data.

Partner APIs

To access partner APIs, a developer needs specific rights or licenses. Partner APIs are not publicly available. They are typically exposed to a public API developer portal that developers can then access via a self-service-mode.

Internal APIs

Also known as Private APIs, Internal APIs are only exposed by internal systems. Internal APIs are not intended for use outside of the company using them but instead are used across various internal developmental teams, enabling better productivity, products, and services.

Composite APIs

This type of API combines different service and data APIs. Composite APIs enable developers to access various endpoints in one call, so they are useful for microservices architecture patterns in which many pieces of information from various services are required to perform a single task. Composite APIs allow users to speed up processes and improve performance to end-users.

Other API Types

There is an alternative way to categorize APIs to do with data and service. The four main types are:

•   Data APIs, which provide CRUD access to underlying data sets for SaaS cloud providers or databases. Data APIs are fundamental for serving the information coming from a SaaS application.
•   Internal Service APIs, which expose internal services, reflect elements of those internal processes and perform other complex actions.
•   External Service APIs, which are third-party services. Developers can easily embed external service APIs into existing company services to add value.
•   User Experience APIs, which leverage various APIs to enable app developers to provide the correct experience for specific devices, such as desktop, tablet, and smartphone.

Web Service APIs

In addition to the above APIs, there are also web service APIs. Four of the most common web service APIs are:

•   SOAP, which stands for Simple Object Access Protocol. The protocol uses XML as a format to transfer data. SOAP’s primary function is to define the structure of communication methods. SOAP uses a machine-readable Web Services Definition Language to publish a definition of its interface.
•   XML-RPC, which is different from SOAP because it uses a specific XML format to transfer data instead of a proprietary XML format. XML-RPC uses minimal bandwidth and is a lot easier to use than SOAP.
•   JSON-RPC, which is similar to XML-RPC, but it uses JSON to transfer data.
•   REST, which stands for Representational State Transfer. Unlike the above web services, REST is not a protocol. It is a set of architectural principles.