Application Programming Interface (API)
API stands for application programming interface; it is a set of functions through which other Apps can communicate and access data from different applications.
An important part of API is ‘Interface’, for the user table or mobile is interface. It takes a request from the user and communicates with the server, then the server processes the request and gets back with the required data.
Below is the diagram of API request processing.
Here client (web app/mobile app) wants to send requests through the internet to a web server but it has no option to communicate. Here the API comes into the picture. It works as a mediator between client and server.
First, the client sends a request through API to the web server and the server process that request sends back required information to the client through the API calls.
Type of the API
There are API classified into four major types :
- Open API’s
- Partner API’s
- Internal API’s
- Composite API’s
Open API’s – It’s also known as public API, which is available without restriction. For example – Google , Microsoft, PayPal etc available for public use.
Partner API’s – Partner API requires authentication to access because of restriction. This API can be accessed after the permission and rights.
Internal API’s – Internal API’s like a private API, it cannot be available for the external users.For example – this type of API can only be accessed by the member of the organization.
Composite API’s – its a bundle of API requests that combine in a single request and call sequentially. In this user make one set of API requests and get the one response.
For example – GraphQL.
API integration is an important and essential tool that gives access to establish connections between applications, access the data from multiple platforms and allow to exchange data, it also helps to automate the process.
For example, in technical terms, without the API integration with shopping platforms, it is impossible to retrieve, add, delete and synchronize the data from e-stores.
These days API integration is the most popular technique in web development and as well as in mobile development.
Testing Of API
“ Testing the application programming interface of the business logical layer of any application is called API testing “.
API testing is used to determine whether APIs return the correct response. It’s considered as part of integration testing. Testing commonly includes testing REST APIs or SOAP web services with JSON or XML message payloads.lso the reason for testing to determine functionality, security, performance of the APIs.
API is also the logic layer, so application often have 3 layers:
- Presentation (Front-end) Layer
- Business al Layer
- Database Layer
So the business layer or the way to implement the business layer in the application is the API, API is the business layer.APIs or service layer directly touches both the data layer and the presentation layer.
How modern architectures work around APIs is the question that suddenly pops up in the mind.
Use of the API
- A private API commonly is acts as an interface to the team to decrease siloed work and smooth out coordinated effort
- Open APIs, then again, furnish outside designers with an approach to effortlessly get to and incorporate data starting with one apparatus then onto the next. An open or public API saves engineers time by permitting them to interface their platform with already existing devices, decreasing the need to create new functions
- To engage advancement and coordinated effort: APIs have been at the bleeding edge of advancement in technology. APIs like Google Genomics allow researchers to easily analyze huge amounts of genetic exploration, assisting them with finding medicines and study how genetics conditions create
- If we want to pass the data to different different clients (web App/mobile App). Then in this case both the Apps use different languages so they can not understand each other’s response. So in this case we can use APIs. It is because every language can understand APIs so it creates a medium between two Apps by which both of them can communicate with each other
To implement the successful API essential steps of test cases explained. API plays an important role in web development and mobile development without it the application would be limited, it enhances the functionality of the applications.