API Types and Their Applications

Morris Muriuki Muthigani

08/31/2023 (8 months ago)

API Types and Their Applications

Application Programming Interfaces (APIs) empower developers to facilitate interaction between distinct software systems or platforms, ushering in novel functionalities and capabilities. However, forging these connections involves the selection of suitable protocols, each presenting its own advantages, drawbacks, and specialization. This article delves deeply into the prevalent API types and protocols, shedding light on their distinctive attributes.

Exploring Various Web API Types

Web APIs come in diverse forms, each tailored for specific purposes and use cases. Here, we delve into the prominent types of web APIs:

1. Open APIs

Public APIs, also known as Open APIs, offer a toolkit of tools, routines, and protocols for constructing software applications. They grant access to application data while safeguarding sensitive source codes from developers. This strategic approach permits companies to extend their services without relinquishing proprietary control over developer outcomes.

Developers find these APIs valuable for crafting innovative applications based on organizational features or service data. Operating much like RESTful APIs, they ensure authentication and authorization, facilitating seamless integration of new programs. The popularity of public APIs has led to the creation of numerous pioneering applications and services.

2. Partner APIs

Partner APIs are specialized interfaces that empower businesses to access data and services from other enterprises (B2B interactions). This streamlined approach allows companies to infuse distinct features into their applications or services by leveraging resources from partners. Such integration optimizes cost-efficiency and time allocation, ultimately enhancing customer experiences and revenue generation.

By incorporating external data like customer feedback or supplementary products, businesses can align partner APIs with their unique business models, leading to innovative offerings.

3. Internal APIs

Internal APIs, as the name suggests, are designed for internal use within an organization. These APIs facilitate data exchange among various components of a system, automating processes. Often proprietary within large organizations, they enable different applications and systems to communicate, creating an abstraction layer that ensures autonomy in modifications and upkeep.

Incorporating advanced technologies and services into existing systems becomes streamlined and efficient with the assistance of internal APIs.

4. Composite APIs

Composite APIs amalgamate multiple APIs into a single interface, providing developers with a cohesive perspective of data from diverse sources. Such integration simplifies data access, especially when dealing with complex applications, frequently encountered in the interconnection of various cloud services.

By offering a unified interface for multiple APIs, composite APIs promote efficient coding practices, eliminating the need for separate code for each individual API. This streamlined approach not only expedites development but also offers cost-effective solutions.

In a realm where software interactivity is paramount, understanding the nuances of API types and their aligned protocols is crucial. This knowledge empowers developers to architect robust systems that fulfill distinct requirements and optimize operational efficiency.

What are the different types of API protocols?

When it comes to programming interface integration between two parties using an API, strict guidelines — known as API protocols — are enforced to regulate interactions.

These rules is enhance efficiency when exchanging data within various applications through standardized communication modes. Some requirements outlined by the API protocols include specifying formatting for request/response exchanges or permissible kinds of data that can be shared, authentication procedures, or security measures for safe information transfer. Following these standards guarantees consistent interactions while ensuring reliable performance.


In today’s landscape, a majority of APIs are powered by REST. Web applications commonly employ REST APIs. These are versatile interfaces for sending and retrieving data through HTTP requests in JSON, XML, and plaintext — among other formats. 

REST (Representational State Transfer) APIs represent an example of these interfaces since they use the principles underpinning the REST architectural design when communicating between clients and servers. This design includes predefined sets of different operations parameters available via standard HTTP methods such as GET, POST, PUT or DELETE while allowing scalability. 

Through APIs, accessing structured data in JSON or XML format is facilitated while also guaranteeing security and accessibility to resources. Adhering to REST principles helps developers create dependable, user-friendly API systems that are capable of being used across devices and platforms.


Web services can also be built using SOAP APIs, which rely on XML messages to enable communication between two applications over a network. 

SOAP has strict rules and rigid messaging standards that can make it more secure than protocols such as REST. These types of APIs are frequently used in enterprise applications, particularly for payment processing and customer management as they are highly secure in nature. 

Creating web services that can be accessed by various clients without being restricted to a particular platform is doable thanks to SOAP APIs. Its secure nature is another important benefit that has made SOAP widely used for transferring highly sensitive information.

GraphQL APIs

If you’re looking for a fast API solution, consider GraphQL. This cutting-edge approach eliminates the need for excessive queries from clients by leveraging its specialized query definition capabilities — hence providing much-needed flexibility during data aggregation. 

Unlike traditional REST APIs, developers can take advantage of an interface capable of on-demand “data querying” with ease. In essence, with GraphQL APIs, users request everything that they want from the backend service all in one API endpoint. This helps them avoid superfluous API calls. By enabling the retrieval of precise data, GraphQL APIs have the potential to minimize data requests and consequentially make applications more efficient. In addition, it enables developers to swiftly incorporate new fields or types in their applications, creating a rapid and streamlined development process.

Webhook APIs

The functionality of webhook APIs primarily revolves around facilitating real-time transmission of data and seamless integration between various web applications. An example of their usage would be sending push notifications to alert users about incoming emails. As soon as specific pre-configured events take place, these APIs automatically trigger messages — or “hooks” — that initiate communication between different software programs. 

Webhook APIs enable applications to remain synchronized and respond to events instantly. These APIs are extensively used for event-based programming where the software can exchange real-time data. They can have varied purposes such as signaling a user after clicking on a link or updating an online store with new items without any manual intervention.


By using APIs, applications can execute remote functions seamlessly over long distances even when hosted on different machines. In distributed systems and microservices architectures where this kind of flexibility is crucially important, there is growing reliance on Remote Procedure Call (RPC) APIs whose implementation typically follows protocols like JSON-RPC or XML-RPC. 

At its core lies the effective RPC protocol, designed to enable efficient data transfers among multiple interconnected computer nodes via networks characterized by various topologies. This interaction occurs via the standard but elegant client-server paradigm whereby servers respond to incoming requests issued by clients. Messages containing requests for a server to carry out a specific task and return a response, known as remote procedure calls, facilitate the communication process between the client and server. RPC APIs are often utilized to manage resources like databases on remote machines or to access web services.

There are other types of APIs as well, but these are some of the most common and widely used. The choice of API type will depend on the specific requirements of the application and the data being accessed.

What are API request methods?

APIs utilize various request methods that define how a client app is allowed to interact with online systems. These particular approaches usually revolve around acquiring and manipulating information stored in those systems. 

To be specific, there exist five popular kinds of API request methods: GET, POST, PUT, PATCH, and DELETE. 

Consequently seeking information is made easy via GET requests, while creating fresh details may only be accomplished through POST logic. Updating older information must be done using PUT protocol, while PATCH may alter it if needed, and DELETE will remove any redundant files. Powerful, dynamic applications can be created by effectively utilizing a combination of methods distinguished by their unique purposes and applications.

Here is a high-level overview of several types of API methods:

GET method: retrieves information or data from a specified resource

POST method: submits data to be processed to a specified resource

PUT method: updates a specified resource with new data

DELETE method: deletes a specified resource

PATCH method: partially updates a specified resource

OPTIONS method: retrieves the supported HTTP methods of a server endpoint

HEAD method: retrieves only the headers of a response without the response body

CONNECT method: establishes a network connection to a resource, typically used for SSL/TLS tunneling

TRACE method: echoes the received request back to the client, for debugging purposes

API methods are typically used to interact with web services or web applications, allowing developers to access and manipulate data or functionality from a remote source.


In conclusion, having a comprehensive grasp of the diverse categories of web APIs, the array of API protocols, and the spectrum of API request methods is imperative for developers aiming to forge contemporary web applications.

Among these, REST APIs stand out as the prevalent protocol, whereas GraphQL emerges as a novel alternative, offering enhanced efficiency and precision in data retrieval. Meanwhile, SOAP, RPC, and webhook API protocols each possess distinct utilities and applications.

The selection of appropriate API request methods hinges on factors such as the nature of the data to be transmitted and the intended actions. Every method brings its own set of advantages and utilities, necessitating careful deliberation by developers.

Ultimately, the choice of web API type, protocol, and request method is contingent upon the specific requisites and objectives of a project. Armed with a clear understanding of these differentiators, developers can make informed decisions tailored to their ventures, leading to the development of sturdier and more impactful applications.

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