How to Use Postman to Test an API
Application programming interfaces (APIs) play an essential role in software development. If you intend to develop an online application or website, you will either need to create an API, use an existing one, or both.
An API takes a request from one software application to another, then returns to the initiating software with a relevant response. Therefore, if your API is defective then your application will experience problems. The Postman platform helps you to keep your APIs functional, by providing API testing among other useful features.
What Is Postman?
Postman is a platform that helps you to work with APIs. It is an API repository, which allows you to store, organize, and use your APIs. Postman’s repository is cloud-based and version-controlled, so it’s the ideal platform for collaborative API development, as well as API development across multiple devices.
Postman allows you to manage every aspect of the API development workflow. This platform provides everything you need to test a complete CRUD API. Some of Postman’s popular features include:
- Workflow recipes
Installing Postman on Your Device
You can download Postman from its official website on a Windows, Apple, or Linux machine. Selecting your machine type starts an automatic download of an executable file. This will install the Postman platform in a few easy steps.
How to Create Requests Using Postman
The latest version of the Postman platform (v9.28.1) launches with the following user interface:
To send a request to an existing API, click the new button in the top-left corner of the Postman interface. This will bring you to the following pop-up window:
The top-left corner of the pop-up window has an option to create a basic HTTP request. Selecting that option brings you to the following interface:
There are several important fields in the request interface. The first field you should attend to is the request method (or verb) field. The default request method is GET, but there are over 10 different methods to choose from.
The five methods that you will use regularly include:
- GET: acquires data from a database.
- POST: adds new data to a database.
- PUT: updates an entire data field in a database.
- PATCH: updates specific aspects of a data field in a database.
- DELETE: deletes data from a database.
The URL field is directly beside the request method field. To test an API, you simply select the request method and provide the appropriate URL.
Testing A Public API in Postman
You can use any public API in this section. The following example uses a news API called Newsdata.io. This API has several query options that return worldwide news. The country-based endpoint has this structure:
You will need to replace the YOUR_API_Key value in the URL with the API key that you will receive after you register with Newsdata.io. Inserting the updated URL into Postman returns a similar output to the one below.
"title": "Apple could be the first to use TSMC's 3nm chip process for M2 Pro",
"[email protected] (Mike Peterson)"
"description": "Apple's 2022 MacBook Pros may pack new M2 Pro and M2 Max chipsets made with TSMC's latest 3nm manufacturing process, according to a new report.M2TSMC, the world's largest semiconductor contract manufacturer, has been steadily building out its 3nm production processes. According to the Commercial Times, Apple could be the first customer to get its hands on those chips. Read more...",
"pubDate": "2022-08-18 15:22:53",
"united states of america",
Postman will return an array of news stories. The output above only displays one example of these news stories.
Now You Can Test APIs With Postman
Postman is a popular platform you can use to test APIs you want to use in your projects. You can maintain a set of resources and use a range of request methods.
Once you’ve tested your APIs, the logical next step is to integrate them into your applications.