For the purpose of this tutorial it is mandatory to have Postman installed which is available has native apps for Windows, OS X and Linux. It is also mandatory to create an account at Algorithmia.

Creating and selecting an environment

Postman’s environment functionality makes it very easy to switch between different environments. A set of variables can be configured per environment and when switching from one environment to another one these will be replaced accordingly. For example let’s create an environment called “production”. Click the “No environment” dropdown in the header and select “Manage environments”.

Manage environment

Select the “Add” button on the popup that is presented to you. Add url and key simNz9pf7hfAQNifdA224K1GFhs1. Don’t forget to replace the secret by your own key.

Manage environment values

Finally select the “Production” environment in the environment dropdown and let’s create our first request.

Manage environment production

Creating a POST request

Enter {{url}}/WayneS/Calculator/0.1.0 in the request field and change the method from GET to POST. We need to add some additional headers as well so add Content-Type application/json, Authorization Simple {{key}}. As you can see, we are using the environment variables {{url}} and {{key}} so when switching environments, those variables will get replaced. The {{...}} format can only be used in the request URL/URL params/Header values/form-data/url-encoded values/Raw body content/Helper fields.

Request headers

Postman also has a few dynamic variables which you can use. For example, {{$guid}} is generating a random v4 style guid, {{$timestamp}} is the current timestamp, {{$randomInt}} a random integer between 0 and 1000. More of those will be added in future releases. But for now, let us just simply enter "x=log(2)" as the raw content of our request.

Request body

Finally let’s hit the “Send” button and if everything goes as expected, we should receive the following response.

Request send

Next we are going to write our test, but first let us save our request into a collection. By clicking on the create collection button on the collections tab, the following popup will be displayed. Simply enter “Calculator” as the name of the collection and hit the create button.

Create collection

Now hit the “Save” button next to the request field. Enter “Log” as the name of the request and select “Calculator” from the dropdown menu.

Save request

Writing a test

A Postman test is essentially JavaScript code which sets values for the special ‘tests’ object. To know which other objects and libraries are available while writing your test cases, make sure you check the following link. Let’s copy following code snippet in the Tests sandbox.

tests["Status code is 200"] = responseCode.code === 200;
var jsonData = JSON.parse(responseBody);
tests["Verify result"] = jsonData.result.x === "0.69314718056";


The test will run each time you hit the “Send” button. Let’s say we need a custom function to set some variables, this can easily be achieved in the pre-request sandbox as shown below:

Custom function

Here we are using the ‘postman’ object and are calling the setEnvironmentVariable function on it, this allows us to assign the result of our function to a variable on the environment scope for later use.

Collection Runner

Let’s assume we want to run several tests at once. Postman has a Collection Runner utility that allows us to just do that, even thousands of tests if we want. To access the runner click on “Runner” in the top header then select “Calculator” as the collection and “Production” as the environment. We want the runner to do that 2 times so enter 2 in the iteration inputfield like shown in the screenshot below.

Runner full

Scroll down and hit the blue “Start Test” button. Following test report will be presented to you.

Runner result

Writing a request and tests for each different permutation of data could get tiresome and tedious. On the test runner screen we are given the option to choose a data file. This data file can be either a CSV or a JSON file, but will allow us to set up data in bulk to be run through the test runner. Create a new csv file and copy following snippet into it.


We need to rewrite the body of our request so it will use the variable of our csv as follows.

Request CSV

We also need to rewrite our test. Like you can see we use the ‘data’ object to call our expected_result variable.

Test CSV

Back to the runner window. Select the “Calculator” collection and the “Production” environment. Click the “Choose Files” button and select the csv file you just created, click the “Preview” button to check for any inconsistenties. As there are 4 entries in our csv we want to use to feed our test enter 4 in the iteration inputfield.

Runner CSV

Hit the “Start Test” button and you will now see 12 green tests. Pretty neat, isn’t it?

Runner result CSV


Integrating Postman tests with build systems can easily be accomplished with Newman. Newman is the command line tool companion for Postman. It can be installed through the Node.js package manager, npm. You’ll find more information on how the install Newman here.

After Newman is installed we can export our previously created collection and environment. Select the ‘Calculator’ collection and hit export and save as my_collection.json.

Export collection

To export the ‘Production’ environment select ‘Manage Environment’ and on the next popup hit export and save as ‘prod_environment.json’.

Export environment

Now run you test with Newman using following command where my_collection.json is the exported collection, my_data.csv the csv, prod_environment.json the environment and -n the number of lines from our csv.

newman run my_collection.json -n 4 -d my_data.csv -e prod_environment.json


In this tutorial we saw how to create a request and a test. We saw how to create a collection and how to run it with the collection runnner and Newman. I hope you enjoyed this tutorial and if you have any question feel free to add these as a comment or to email me at

Gregory Rinaldi is a Software Engineer at Ordina Belgium, he is a maker that does his best work at night, he is passionate about all Java- and JavaScript related technologies and has a strong focus on reuse and automation. Currently he works on UnionVMS an Open-Source Asset Monitoring System.