Installation

To install Postman, just go to this link and download the right version for the OS you use.

How to do a simple GET ?

Now, you should see the following screen :


Click the Request button at the top-left of the modal, and you'll get on the Save Request screen.

Give it a name, select a collection and save it.

From there, you'll be able to send a request. For exemple, you can hit the HTTPCat API. Just enter the https://http.cat/[status_code] URL in the dedicated tab, with the status code of your choice. Press Send and you'll see the response just below.

A first POST with a JSON body

To do a POST request, we are going to hit the https://jsonplaceholder.typicode.com/ URL, on the post route.

So from the same screen, select POST instead of GET, and enter the URL in the dedicated tab.

The API we're hitting enables us to send any JSON body, and sends it back in the response, adding it an id. Let's then send a random object.

Go in the Body tab, check the raw radio button, and make sure that you selected JSON (application/json) on the dropdown on the right.

Now let's right our JSON object. There are a couple things we need to be careful of when we right a JSON object, especially when you are used to do JavaScript.

Use quotes for the object keys

🚫

{
	key: "string"
}

✅

{
	"key": "string"
}

Use double quotes

🚫

{
	'key': "string"
}

✅

{
	"key": "string"
}

• mettre des double quotes et pas des singles quotes
• body d'un POST en 'raw'
• Si c'est un JSON penser à spécifier 'application/json'
• pas de virgule après le dernier élément de ton json
• false et true sont en minuscule