API, webservices: definitions and differences

What is the difference between an API and a webservice? In which case do we use an API and in which case a webservice? To understand everything, and it will only take you a few minutes, it’s in the article.

Definition of an API

To begin with API stands for “Application Programming Interface” which could translate to “Application Programming Interface”. You’re going to tell me that it doesn’t help you understand what an API is any more than that. Let’s go on. A good picture is better than a thousand words! In this case we will tell you to imagine that an API is a bit like a “bridge” or a kind of “gateway” between two applications. These applications use this “bridge” in order to communicate with each other and send data to each other. A mobile application can communicate with software which can communicate with a web application etc.

An API provides access to a service such as data or functionality provided by a third-party system. The third-party system is then said to expose an API. The API helps two applications communicate easily with each other. A dialogue therefore takes place between an application consuming a service and another application which will produce this service.

Concretely, a CRM could, for example, send data to an e-commerce site when a customer connects to his personal account and consults the status of his orders.

The API describes the methods by which one application will communicate with another. And APIs are numerous, you use them every day when you browse the web, without even knowing it! For example when you use Instagram on your mobile phone, when you consult a Google Maps integrated in a home delivery site etc.

Note that there are 4 different types of APIs.

The 4 types of API

Composite APIs: A composite API aims to speed up an execution process. This API will group requests from multiple APIs sequentially into a single API, that is, within a single API call. This helps improve API performance. Rather than making multiple calls to the server, a single call is made and a single response is sent.

Partner APIs: a partner API has rights. To be able to access it, you must have the required right or license.

Open APIs: an open API is accessible to everyone. Anyone can access it, it is public and can be used without restriction. We can also say that this API is open source.

Internal APIs: an internal API also called a private API is very often used in companies. These APIs are specifically used by internal company tools.

Now, in order to differentiate an API from a webservice, let’s start by defining what a webservice is.

Definition of a webservice

A webservice, in French web service, is a function whose role is to make a service available via the Internet. The webservice is an interface between two applications, and allows them, like the API, to communicate with each other. The webservice allows applications to communicate with each other even if they work with different languages. The most well-known webservices are of the SOAP, REST and HTTP types.

How a webservice works

Step 1: A user on a computer or mobile makes a request. We call him the client. Its request represents a request which is sent in a specific language: XML, http or even JSON.

Step 2: The request from the client is sent to a remote server via a SOAP, REST or HTTP type protocol.

Step 3: The server will send a response which will have the same format as the protocol of the request.

It is true that reading the description of a webservice, in its operation, it has many similarities with the operation of an API. But then how are they different?

How to tell the difference between an API and a webservice?

As explained previously, APIs and webservices are “gateways” which allow two applications to communicate with each other. The only difference between these two concepts is that the webservice’s mission is to facilitate communication between two machines. Unlike the API, which will serve as the interface used for communication between the two applications.

An API does not necessarily need a network to function, whereas a web service will always need a network. To put it simply, a network is a grouping of at least two computers that exchange data with each other. Therefore, not all APIs are webservices, but all webservices are APIs.

The API is a lightweight architecture while the webservice does not have s a lightweight architecture because it needs protocols to function: send and receive data. An API can communicate in any style it wants, there are no restrictions while a webservice can only communicate with SOAP, REST and XML styles.

To conclude this article, which we hope will have answered your gray areas and questions, we will say that APIs were created so that applications can communicate with each other. They are part of the daily development of web, mobile or software applications.

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