The most common API types

Let’s first categorize what is the server and what is the client. Server refers to the data and ways how to update it. On the other side, web application or a native mobile application serve as clients. Logically, different situations ask for different servers and different clients.

We will stress out that APIs have the following functions:

  •    to connect and guide through communication of two or more pieces or software,
  •    to enable communication between services.

Do you know why APIs are so popular? APIs do multiple savings – of your time and resources. Concluding, APIs make life simpler. No one would want to code for hours when there is a possibility to finish the job with one click only.

APIs come in many shapes and sizes, but we decided to present you the most common ones. Each of these behaves differrently as it serves for a specific need and uses particular tools.

Basics of API

Basic API types are Open and Public APIs. Just like you can suppose, the first API category is available for the use around the world. Open APIs are mostly free, but some of them take orders on the Internet.

People usually think that Open APIs have much more users. The proportion among Private and Open APIs’ users is 70:30!

Private APIs serve to companies. Business work with them privately, inside the network. Yet, this creates a confined type. Developers need some ideas from the outside in order to maintain or ameliorate a company’s functioning. That is why they turn Private into Open APIs. A great number of the Open APIs today once were Private APIs.

Numerous API types’ subcategories came up over the years, but the broader distinction between the types is still the most important. There are some differences among these broader categories too. Each of them is determined by the client-server connection they provide. These servers we mention are APIs actually.

Production API

Every application needs a production API sooner or later. This server’s (API’s) function is to send real data, update it and to ensure the needed permissions. This API detects if users have permission to update or change information. Production APIs are really important, as they bear the whole application’s traffic. Make it scalable and fast. To conclude, most applications, such as the stoplight app, already have a production API.

Fuzzing API

If you are used to a predictably API behavior, fuzzing API will confuse you a bit. It actually does everything in an unexpected way. It surely does return data in a way the client expects, but the data is completely randomly organized. It is true that fuzzing API seems shallow, but its simple logic gathers data generation. Fuzzing API will illustrate a bug, but you would have to figure out what caused the problem in the first place. Even though it lacks sophistication, fuzzing API is still great.

Mock API

Among the APIs we are presenting to you in this article, mock API is probably the simplest. That is why beginners like it so much. All the setup of the mock API is completely explicit. You don’t have to use a custom test API anymore, just mock what you want. Mock API is a general program, so you don’t have to change its code when you want to get across to another project. Mock API’s greatest feature is universality.

Development API

If you would want to get everything thoroughly tested before the launch of the application, then the development API is a perfect choice. Some people even define it with the term “fake” API. People understand this API differently, that is why it is called fake.

You should work with the development API before you use the production API. What is more, the development API would be much more important even if the production API is available. Its biggest advantage is tooling.

There is only one mistake that you can make with the development API – to run tests against it. When it comes to testing, mock API is the greatest.


The APIs we talked about in this article offer you much more than a plain API production does. You can make customizing responses, improve the test expressions, detect the problems. They also provide you with flexibility and dramatically improve your productivity.

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