What are The Types of APIs? – Know The Every Unknown

Using the APIs (Application Programming Interfaces), you can reveal data or connect devices, systems, apps, and datasets. To harness effective API management and API performance, it is crucial to choose the right type of API.

Types of APIs

In general, four key types of APIs exist, including partner, public, private, and composite. The term type in “types of APIs” refers to the usage scope.

Partner APIs

The Partner API refers to the API that is for the usage of the business or organization partners (developers). They have exclusive permissions to use this API. To foster effective business partnerships, third parties can harness easy access to these APIs. This way, business partners can ensure the facilitation of smooth B2B activities.

When two different organizations need to share crucial data, they use Partner APIs. For instance, the health department of the country and specific hospitals in the same country use Partner APIs. Through Partner API, you can control the access to permissions, authorization, and authentication of third-party ties partners. There is no need to monetize these APIs. This is because each partner receives payment depending on their services for API usage.

Public APIs

You can also refer to public APIs as the APIs that any outside business or developer can use. Other names for public APIs are External APIs or Open APIs. The organization whose business strategy involves data or app sharing with any outside developer or business builds Public API.

To use such APIs, you don’t need high-level authorization or authentication. You can also monetize these APIs by imposing costs on single usage.

Private APIs

The Private API has another name referring to Internal API. You can use this API within a specific business to share data or connect systems. Consider this, for instance, the Private API may join the HR (Human Resources) department with the organization’s payroll department.

There is no strong authentication or security system that exists for the Private API usage. This is because the Private API features an intention of internal usage within the business. The continuously changing regulatory compliance and threat awareness have a great impact on the enterprise’s API strategy.

Composite APIs

The composite APIs involve combining two or two plus APIs for the facilitation of smooth interdependent operations. With the help of these APIs, you can solve complicated or closely related behaviours. You can experience high-end performance as well as speed using these APIs in comparison to singular APIs.

Types of APIs Architectures and Protocols

To exchange data and commands, the APIs require architectures and protocols. These are nothing but the constraints, rules, and structures that guide the operation of an API. There are three main API architecture and protocol categories, including SOAP, RPC, and REST. Each of these protocols features different characteristics and serves other purposes.


The term SOAP refers to (Simple Object Access Protocol). World Wide Web Consortium defined this term. You can use it to design web APIs, particularly with XML. SOAP is completely compatible with the different protocols of communication, including IP/TCP, HTTP, and SMTP. It does not depend on the specific style and offers customization. This allows you to create SOAP APIs in multiple ways and induce desirable functionalities and features.

The SOAP functions in defining the:

  • Processing of message
  • Included modules and feature
  • Supported protocols of communication
  • Message construction for SOAP


The term RPC refers to (Remote Procedural Call). Using this protocol, you can send different parameters and retrieve results. RPC functions for the execution of processes or actions. With RPC, you can make use of two languages, including XML and JSON, when coding.


The term REST refers to (Representational State Transfer). A widely employed approach in building or designing APIs. The REST depends on the server or client approach. This plays a key role in separating the API’s back or front ends. You can enjoy complete flexibility in implementation as well as development of API. REST does not save status or data between requests, which is why it is stateless. You can enjoy caching with REST. This way, you can store responses for time-independent or slow APIs. The REST APIs are also pronouncedset upESTful APIs. You can setup communication directly or through intermediaries using load balancers or API gateway.

Selecting The Right API

No matter if you want to use pre-build API or want to build custom API. Certain factors need your (developers) attention including:

Complete and Clear Documentation

Similar to the software building, you need to set in place the comprehensive documentation for APIs. These documents guide developers, offer usage references, and reference use cases. They collectively help the developers to apply the API successfully and quickly.

Keep it Easy

Make sure the structure and the design of the API are easy to set up and well-adaptive. Setup easy methods for API acquisition, including account sign-up or downloads. Apart from this, we offer knowledgeable and solid support to developers against questions on the usage of the API. If you ignore this factor, then developers will replace using this API with easier-to-adapt APIs.


Please note that an API is user-friendly only if it possesses intuitive and sensible call structures. The inconsistent and cumbersome responses or calls make an API less usable, regardless of its power or comprehensiveness. Multiple things such as clarity, simplicity, compatibility, and consistency are what make an API good or preferable.

Reliability and Stability

The API refers to good APIs only if they pass through bug testing and feature performance and scalability metrics. This includes how many calls an API can handle per second or relevant factors. The developers do not use those APIs which are unreliable and feature inconsistent performance. Make sure that the third-party APIs are robust and easily accessible.

Safety and Security

To ensure the effective usage of the API, you need to set up proper authorization and authentication. This allows you to enjoy better security while sharing the data across APIs. No one can steal or snoop into your data because of encryption.

Practical Examples of API Usage

You cannot ignore the importance of APIs as they constitute the success of today’s age of software. Some key examples include:

APIs for Social Media

Different social media channels, including Facebook and Twitter, today use APIs to facilitate effective communication by tweeting endpoints. For instance, twitter bots are a practical example.

Authentication and Login

To facilitate single sign-in, highly integrated apps depend on API in today’s age. For instance, an app may ask you to “login using Google/FB”. This prevents you from creating a new account for that specific app.

Service and Widget APIs

You can integrate different functions and features of APIs. Search engines such as google retrieve data from service providers using APIs. This includes weather reports, news, ocean tide patterns, etc. Google Maps, for instance, utilizes an API to retrieve location data for various locations around the globe.

Payment or Financial APIs

Banks connect users to their back-end systems remotely, all through the API. This way, users can check their balances, conduct deposits, e-payment transfers, conduct shopping, etc.

Booking and Travel APIs

For ticket purchases as well as airline schedule check-ups, you use the airline APIs. On the other hand, to search for hotel availability or deal with booking, you also use hotel APIs. The airline or hotel has apps that facilitate booking and get insights on costs and special discounts, all through APIs.

Ream More:

What is an API? – Understanding Main Concept

What is API management? – Concept, Tools, Benefits