Meaning of API (Application Programming Interface)

API (Application Programming Interface) is an acronym for application programming interface, and is an interface for connecting software and applications. API also refers to the data format and procedure for calling functions and data used in a specific program from an external program.

The advantage of APIs is that when configuring a program, you can simply write a function to operate using the API, and if the API is similar, you can achieve the same behavior even in external programs. Normally, when developing software or applications, it takes a lot of effort and time to implement various functions from scratch. However, by using APIs, functions can be implemented simply by writing code that calls the API. In fact, even if a service has been upgraded many times, there are many cases where the new version calls the same API that was used in the past version.

In a broader sense, API also includes the rules of the standard library of a programming language. A typical example is “Java API”. In addition, in some cases, functions that provide programming languages ​​are also included as part of the API.

Also, API is sometimes expressed as Web API, but there is no problem in considering these definitions as the same. Both refer to interfaces between applications and systems.

merit

By using an API, you no longer need to write and program the code for all the functions you want to implement; you only need to code the functions to work using the API.

This means developers don’t have to develop applications from scratch.

This allows for consistent implementation in external programs by using similar APIs.

security

APIs can control access to devices and software that applications do not necessarily have permission to use. Therefore, APIs can also play an important role in security.

In other words, APIs allow you to connect to the original information while controlling access and maintaining security.

The publisher can decide how to connect and who has access rights.

In addition, by using APIs provided by payment system operators, it is possible to enter payment information (credit card, etc.) within your own system, and that information can be sent and processed from the operator’s API. You can.

This eliminates the need for your company to manage sensitive information (important customer information such as credit cards). You can reduce points such as security during system design.

Usage example

As an example, consider a bookseller.

Booksellers and customers can share inventory status through the use of APIs. Booksellers can centralize their inventory information in one place instead of distributing it by giving their customers access to the data through APIs.

Booksellers can also make changes to their internal systems without any impact to their customers, as long as they don’t change the behavior of the API.

Additionally, the public API enables book sellers and other developers to create apps that help customers find books.

What is API collaboration?

It is useful to understand not only APIs but also API collaboration. API collaboration, as the word suggests, is the use of APIs to collaborate. For example, in the case of online shops, the API of the credit card company is used when making payments. In other words, the credit card company and the online shop’s payment function are connected via API.

When making a payment at an online shop, it is extremely dangerous to save your card number, expiration date, etc. directly on the online shop’s server. There is a high possibility that it will be misused, and it is undesirable from an information system and security perspective. Therefore, when online shops use the credit card company’s API, the credit card company can directly recognize the user’s information.

The online shop requests the credit card company through API collaboration, saying, “The user is trying to make a credit card payment, so please confirm.” The credit card company then completes the authentication through the API, and the user can actually make the payment.

In addition to the online shops mentioned above, API collaboration is used in all kinds of cases, such as login functions and electronic money payments. The basic mechanism of API is “response” and “request”. The response is the provider of the API, and the request is the consumer of the API. Applying the previous example, the response would be the credit card company and the request would be the online shop. In other words, there is no problem in understanding that the API plays a role like a bridge between the response and the request.

When understanding the overview of APIs, be sure to also deepen your understanding of API collaboration.

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