In my last blog post I explained how to authenticate requests to Microsoft’s legacy SharePoint REST API using Postman. This post builds on that work to store our access token as a Postman environment variable and to then send POST requests to the SharePoint REST API to create new items within an existing SharePoint list.

If you were following along previously, the last thing we did was to request an access token to use in future requests. We’re going to write a couple of lines of JavaScript code within Postman which will parse the API response containing the access token and add it to our previously-created Postman environment.

You should still have a Postman tab open ready to send a request to the following URL:

https://accounts.accesscontrol.windows.net/{{realm}}/tokens/OAuth/2

Click on the ‘Tests’ tab. In the empty window, add the following two lines of code:

const json_response_body = JSON.parse(responseBody);
postman.setEnvironmentVariable("appReg_bearerToken", json_response_body.access_token);

Click ‘Send’ to send our POST request. You should receive a response body containing an access_token key/value pair. The value of the access_token key will now have been added as the ‘Current Value’ of our appReg_bearerToken Postman environment variable. You can confirm this by clicking the eye icon next to the environments dropdown and checking the environment variable values.

We’re now ready to create a new item within an existing SharePoint list. To do so, we need to know the ListItemEntityTypeFullName of the list. Let’s open a new request in Postman, which we’re going to send to the following URL (replacing contoso with your tenant name, and ‘Test list’ with your own list name):

GET https://contoso.sharepoint.com/_api/web/lists/GetByTitle('Test list')?$select=ListItemEntityTypeFullName
Authorization: Bearer {{appReg_bearerToken}}
Accept: application/json;odata=nometadata

Before sending, let’s add a test to this Postman request which will grab the ListItemEntityTypeFullName value and store it as a Postman environment variable. Click the ‘Tests’ tab and in the empty window add the following two lines of code:

const json_response_body = JSON.parse(responseBody);
postman.setEnvironmentVariable("ListItemEntityTypeFullName", json_response_body.ListItemEntityTypeFullName);

You should receive a response body which looks something like the following:

{
    "ListItemEntityTypeFullName": "SP.Data.Test_x0020_listListItem"
}

The value of the ListItemEntityTypeFullName key will now have been added as the ‘Current Value’ of our ListItemEntityTypeFullName Postman environment variable. You can confirm this by clicking the eye icon next to the environments dropdown and checking the environment variable values.

We’re now ready to create our test item in our existing SharePoint list. Open a new Postman request, which we’ll be sending as a POST. Use the following details, where contoso is replaced with your own tenant name and ‘Test list’ is replaced with your own SharePoint list name (note the double underscore before metadata):

POST https://contoso.sharepoint.com/_api/web/lists/GetByTitle('Test list')/items
Authorization: Bearer {{appReg_bearerToken}}
Accept: application/json;odata=verbose
Content-Type: application/json;odata=verbose

{
    "__metadata": {
        "type": "{{ListItemEntityTypeFullName}}"
    },
    "Title": "My test item"
}

Send this request and you should receive a 201 status code in response, as well as a lengthy response body. Check your SharePoint list and you should see that the item has been successfully created.

We can also use the API to retrieve this item. Create a new Postman request and send the following (replacing contoso with your own tenant name, ‘Test list’ with your own list name and 1 with the id you will have received in the previous response body after creating your item):

GET https://contoso.sharepoint.com/_api/web/lists/GetByTitle('Test list')/items(1)
Authorization: Bearer {{appReg_bearerToken}}
Accept: application/json;odata=verbose

You should receive a 200 status code in response, as well as a response body containing your chosen SharePoint list item.

In my next blog post I’ll look at how we can use the SharePoint REST API to add attachments to our list items.