Developers are all too familiar with APIs, as these interfaces have been part of their toolset for years. However, even us regular folks also use APIs, although we’re often not aware of it. For business organizations, APIs can serve as powerful tools that enhance business processes, create better user experiences, and accelerate growth.

What is API?

API stands for Application Programming Interface. It is a set of programming code that defines the functions, procedures, and protocols that allow applications to transmit data and interact with other applications, services, and operating systems.

APIs are everywhere in the digital world. You use an API whenever you send a direct message, use your smartphone to check the weather, search online, or use any software application.

How does an API work?

APIs provide the building blocks that developers need when creating a computer program. They also serve as intermediaries between applications. You can think of them as middlemen or liaisons that let applications talk to each other. They receive requests and send responses between different applications.

Let’s say you’re shopping online. You simply add your items to your cart, provide your personal and credit card information, then wait for the delivery. But the process isn’t as simple as those three steps. There are dozens of other processes that happen in between that you don’t really see. 

APIs are at work in most of these processes. When you click on a buy button, an API transmits that data to the website, which then adds the item to your cart. Other APIs are involved in payment processing and shipping procedures.

What Are the Types of API Protocols?

To leverage different types of APIs, certain protocols are set in place. These protocols indicate defined rules for API calls and specify data types and commands that can be accepted.

Remote Procedural Call (RPC)

This is the oldest and simplest type of API. It uses either XML or JSON for encoding calls. While it is a very simple protocol, its architecture is tightly coupled making it difficult to maintain or update. A developer has to go through several documentations to understand how a specific change affects other APIs.

Simple Object Access Protocol (SOAP)

SOAP is the first to standardize the way applications use network connections to manage services. However, it involves strict standards and can also be resource-intensive. So, save for existing on-premise scenarios, most developers prefer to use REST instead.

Representational State Transfer (REST)

REST is the preferred standard for building applications today. It is simpler than traditional SOAP-based web services and is easier to maintain and update than RPC. REST is stateless in nature and maintains client-server independence. This means that changes on the client do not affect the server and vice versa. 

It also supports a layered architecture that is loosely coupled and allows for encapsulation, making it easy to update. Moreover, it enables cache that improves user experience by facilitating faster and more efficient processes.

What Are the Main Types of API?

There are many types of APIs but the three main ones are the following:

Open API

Also called Public APIs, these are open to external access, with minimal restriction, and are used by developers anywhere. Open APIs are the most visible types, as they focus on external users. Google Maps, Yahoo search, and most B2C apps use open APIs.

Partner API

B2B and B2C apps also use partner APIs that require validation for external access. They are also visible like Open APIs, but access is restricted. They are typically used to communicate beyond the boundaries of a business organization.

Internal API

Used by internal developers, internal APIs are hidden from external users and are considered Private APIs. These are not meant for public access and are dedicated for use across different internal development teams. A2A, B2B, B2C, and B2E apps use these APIs for better productivity and efficiency.

Composite API

Composite APIs are combinations of service APIs that allow developers to access multiple endpoints in one call request. These are useful for B2B and B2C apps that require information from different services to perform one task.

What Are the Common APIs for Business?

The applications and systems we use do not rely solely on one API. For instance, a typical eCommerce site involves the use of dozens of different APIs including the following:

  • Product Information API
  • Orders API
  • Inventory API
  • Channels API
  • Authentication API
  • Payment API
  • Shipping API

For business organizations, the most useful APIs are:

  • Google Analytics API
  • Yelp Fusion API
  • Real-Time Messaging API
  • Gmail API
  • Adobe Sign API
  • FreshBooks API
  • Agile CRM API

There are hundreds of other APIs that business organizations can utilize to improve their workflow processes, enhance customer experience, and drive business growth. While APIs seem best left to developers, understanding them and how they work is also important for individuals running a business.

About the Author
With over 15 years in content marketing, Werner founded Influencer Marketing Hub in 2016. He successfully grew the platform to attract 5 million monthly visitors, making it a key site for brand marketers globally. His efforts led to the company's acquisition in 2020. Additionally, Werner's expertise has been recognized by major marketing and tech publications, including Forbes, TechCrunch, BBC and Wired.