Ensuring that the API response is correct is something that you will be doing a lot when working with APIs. The Postman response viewer will make this task much easier for you.
An API response consists of the body, headers, and the status code. Postman organizes body and headers in different tabs. The status code with the time taken to complete the API call is displayed next to the tabs. You can hover over the status code to get more details about the code. Mostly it will be the default description as mandated by the HTTP specification, however, API authors can also add custom messages.
If a request has been saved in a collection, you can save responses for that request. Once the response has been returned, click the Save Response button. Enter a name to call your saved response. All responses saved for a request will be available whenever you load the request. Expand the API description above the request URL to view and select the saved responses.
The Postman Body tab gives you several tools to help you make sense of things quickly. The body can be viewed in one of three views - pretty, raw, and preview.
The pretty mode formats JSON or XML responses so that they are easier to look at. Nobody wants to scroll through a minified single line JSON response looking for that elusive string! Links inside the pretty mode are highlighted and clicking on them can load a GET request in Postman with the link URL. For navigating large responses, click on the down-pointing triangles (▼) on the left to collapse large sections of the response.
For Postman to automatically format the body, make sure the appropriate Content-Type header is returned. If the API does not do this, then you can force formatting through JSON or XML. You can force JSON formatting under the General tab within the SETTINGS modal by selecting “JSON” from the “Language detection” dropdown.
Finding items in responses: You can use CMD/CTRL + F to open the search bar, and CMD/CTRL + G to scroll through results. See complete set of keyboard shortcuts.
The raw view is just a big text area with the response body. It can help to tell whether your response is minified or not.
You can maximize the body to occupy the whole Postman window. In case you plan on spending a lot of time with the response, this is the way to go.
If your API endpoint returns an image, Postman will detect and render it automatically. For binary response types, you should select “Send and download” which will let you save the response to your hard disk. You can then view it using the appropriate viewer. This gives you the flexibility to test audio files, PDFs, zip files, or anything that the API throws at you.
Headers are displayed as key-value pairs under the Headers tab. Hovering over the header name can give you a description of the header according to the HTTP spec. If you are sending a HEAD request, Postman will show the headers tab by default.
Postman automatically calculates the time it took for the response to arrive from the server. This is useful for some preliminary testing for performance.
Postman breaks down the response size into body and headers. The response sizes are approximate.
Cookies sent by the server are visible in a dedicated tab. To manage cookies in Postman the native apps, use the MANAGE COOKIES modal. If you’re working in the Postman Chrome app, you can use the Interceptor extension to help manage cookies.
Along with everything that you get from the server for the request, you can also see the results of the tests that were run against the request. Learn more about testing in Postman.