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Request parameters

Learn to send GET and POST HTTP requests with parameters using a graphical interface.

Postman

In this section you'll learn how to use Postman, which is also a client like curl, but with a graphical interface, which is a bit easier to use and configure.

Go to this page to install Postman on your machine.

Drag the Postman program in your Applications directory if you're on Mac, or follow the installation instructions if you have a different system.

On the first launch, Postman should welcome you with the following screen.

Like curl, we can use Postman to send HTTP requests to web servers, and inspect the responses we receive.

Click on the + icon next to the "Overview" tab to open a new tab.

There are quite a few different options to configure the request we want to send, but the more important part (circled in red on the screenshot below) is where you set the request method and the URL.

Leave the method set to GET and paste the URL https://jsonplaceholder.typicode.com/todos/1, then click the "Send" button.

You should get the JSON response in the bottom panel of the program:

We can see two important things about the response:

  • its content (the JSON data).
  • its status code (200 OK - on the top-right corner of the panel).

In the following exercises, you'll practice by sending requests to the Postman Echo website, which returns some pre-defined responses to some requests. You'll learn about some components of GET and POST requests.

Request Parameters

  • The GET method is often used to query or retrieve information from the server. The exact data returned depends of the implementation of the web server.

    A GET request can also contain query parameters, as part of the URL.

  • The POST method is often used to send data to the web server (usually to create or update data, or just send some information). What is done with this data depends of the implementation of the web server.

    A POST request can also contain body parameters. Contrarily to query parameters, they are not included in the URL, but within the request body itself.

There are more HTTP methods, but we'll cover them a bit later.

Demonstration

Video demonstration

Exercise One

Use Postman to send a GET request to the URL https://postman-echo.com/get.

In the "Query params" section, set a query parameter with key title and value 'Welcome'. Then send the request.

You should get the following JSON response, and the status code should be 200 OK:

{
    "args": {
        "title": "Welcome",
    },
    "headers": {
        // (omitted).
    },
    "url": "https://postman-echo.com/get?title=Welcome"
}

You'll note that Postman automatically added the parameters at the end of the URL, using a syntax such as ?title=Welcome — this is the way query parameters are sent in GET requests, inside the URL itself.

Solution video

Exercise Two

Use Postman to send a POST request to the URL https://postman-echo.com/post.In the "Body" tab below the URL field, select the option "form-data", and set a parameter with key title and value 'Welcome'. Then send the request.

You should get the following JSON response, and the status code should be 200 OK:

{
    "args": {},
    "data": {},
    "files": {},
    "form": {
        "title": "Welcome"
    },
    "headers": {
        // (omitted).
    },
    "json": null,
    "url": "https://postman-echo.com/post"
}

Solution video

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