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REST API interfaces and programming interfaces

What is a REST API?

A REST API is the most conventional type of application programming interface on the World Wide Web. We explain application areas and use cases.

Rest API

What does REST stand for?

RE stands for REpresentational, the S for State and the T for Transfer. This results in Representational State Transfer. REST is a type of software architecture with which any Interface between different systems that uses HTTP for their communication is described. The REST paradigm states that when data is transferred between two clients, no information is retained by the data transfer service itself - the traffic is unique and self-contained.

An example: You log in to PayPal with your login data and are authenticated by the service. At your next session, you have to log in again because no authentication was saved in the previous login process. More to payment providers such as PayPal.

Who is the client of a REST API?

Often native apps (Android, iOS), an Internet browser (Google Chrome, Safari, Microsoft Edge, etc.) or virtual assistants such as Alexa or Google Home clients of a REST API. Of course, devices such as a smart radiator can also be clients.

What does RESTful mean?

An API is RESTful if it adheres to the norms of the API REST standards.

What is REST API?

What makes a REST API?

The main characteristic is the loose client-server coupling: client and server do not need any exchange beyond that of the data. In concrete terms, this means that the server is not "interested" in what the client does with the data. The client, in turn, is not "interested" in what the server implementation looks like either. 

Secondly, a REST API is stateless, so to speak, because each API call (or API call) that arrives at the server is independent. For accessing, creating, updating and deleting resources, the following HTTP verbs are used while maintaining the order: GET, POST, PUT, DELETE. If you request information on a web page, this is a GET. A POST happens, for example, when you leave your contact details on the World Wide Web.

Thirdly, API calls can be cached so that the same resource does not experience multiple requests.

Fourthly, it is important to mention that a REST API is uniform: each resource must have a unique Uniform Resource Identifier.

A REST API can use the same methods to query a third-party server that are used to display page information or page forms from the same website. For this reason, the third-party server can be queried using a REST API provided by the API Editor provided URL can be queried.

An example of a REST API

A REST API is a way for two computer systems to communicate with each other over the Internet. It is a set of rules for creating web services that allow different systems to communicate with each other. Here is a simple example of a REST API that allows a client to retrieve a list of users from a server:

					GET /user HTTP/1.1

The above API call is made using the GET method. It is used to retrieve data from the server. The path "/users" indicates that the client wants to retrieve a list of users. The server then responds with a list of users in a format such as JSON or XML.
There are many other methods and functions that can be used in a REST API, such as POST (to send data to the server), DELETE (to delete data from the server), and authentication.

An API is not one-way

Where there is a request in the form of an API call, there is also a response. The response is in one of two specific return formats, JSON or XML. In some circumstances the API Development must have been made in such a way that the user can choose the return format of the REST API.

A well-built (RESTful) Interface is usually easy to read and the corresponding API documentation is clearly formulated, as is the case with the Youtube Data API, for example.

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Example of how to use the GET function in a REST API

Imagine that a third person maintains an address book with all your contacts for you. You can 1. extract information from this address book via API calls (i.e. GET requests) and 2. add information to it via API calls (POST). Now you want to know who the number that just called your mobile phone belongs to (e.g. 09732 30 24 984, the number of appleute).

To do this, perform a GET request to the address of your address book stored in the API documentation, for example

Here, you are searching for the address entry based on the phone number. The restful API will be able to answer you in the appropriate return format:

  • Phone number: 097323024984
  • First name: Marc
  • Last name: Mueller
  • Company: appleute

The result is unique because of the uniqueness of the phone number. If, on the other hand, you were to search for "Mueller", you would possibly have several entries, because "Mueller" - being a very common surname in Germany - may occur more frequently in your address book. So much for GET requests to extract or request information via the so-called REST API.

Example of how to use the POST function in a REST API

The mechanism for the POST action is similar to that of the GET request. Imagine that you don't want to request information, but to pass it on. So in a GET request, you want to "post" something. In a figurative sense, posting is done via a kind of contact form or contact template, where the individual components of the shared information are passed on via specified contact form parameters to the Interface communicated. In this way, information can be passed on to a third-party provider and its receipt or status can even be confirmed after receipt.


1. what is the purpose of REST API?

REST APIs are used for a variety of purposes. Some common use cases for REST APIs are:

To retrieve data: You can use a REST API to retrieve data from a web server and display it in your application.

Updating data on a web server: With a REST API, you can update data on a web server by sending a PUT request to the API.

Create new data: To create new data on a web server by sending a POST request to the API.

To delete data: You can use a REST API to delete data from a web server by sending a DELETE request to the API.

Third-party integrations: Many companies offer APIs that allow developers to integrate their products with other applications.

Microservices: REST APIs are an essential part of the microservices architecture. They are commonly used to create small, independent services that can be combined into larger applications.


2. which APIs are commonly used by developers?

Some of the APIs used by developers:

Google Maps API: The Google Maps API allows developers to access map data and incorporate it into their own applications.

PayPal API: The PayPal API allows developers to process payments and manage financial transactions.

Stripe API: The Stripe API allows developers to process payments, manage subscriptions, and perform other financial transactions.

GitHub API: Using the GitHub API, developers can access data from the popular code repository platform and perform operations such as searching for repositories, managing issues, and creating pull requests.


How is an API different from a REST API?

API stands for "application programming interface". An API is a set of rules that defines how two software programs should communicate with each other. It defines the types of requests that can be made, the way in which data is transferred, and the format of the data.

A REST API is short for Representational State Transfer API. It is a special type of API that conforms to the architectural style of REST. These APIs use a unified interface for communication that makes it easier for different systems to communicate with each other.

4. is a REST API a type of web service?

A REST API is a type of web service that uses the REST architectural style. REST APIs are based on HTTP and use HTTP methods (such as GET, POST, PUT, DELETE) to perform operations on resources. 

They can return data in various formats, such as XML, JSON, or HTML. REST APIs are typically used to expose the functionality of a web application or service, and are designed to be easily accessible over the Internet.

REST-API Development: Consult experts

For questions about or applications (API to PayPal, YouTube, ERP, etc.) of REST APIs, please contact us at API Development Agencies like appleute to the side.