Postman Sandbox

Note: The functionality described here is exclusive to Postman's native apps for Mac, Windows, and Linux.

Global functions (pm.*)


require(moduleName:String):function → *

The require function allows you to use the sandbox built-in library modules. The list of available libraries are listed below. The list links to their corresponding documentation.

A number of NodeJS modules are also available to use in the sandbox:

In order to use a library, simply call the require function and pass the module name as a parameter and assign the return of the function to a variable.

var atob = require('atob'),
    _ = require('lodash'),


arrayOfStrings = ['string1', 'string2'];

base64Strings =, atob);




The pm object encloses all information pertaining to the script being executed and allows one to access a copy of the request being sent or the response received. It also allows one to get and set environment and global variables.

The object contains information pertaining to the script being executed. Useful information such as the request name, request Id, and iteration count are stored inside of this object.


    Contains information whether the script being executed is a "prerequest" or a "test" script.


    Is the value of the current iteration being run.


    Is the total number of iterations that are scheduled to run.


    The saved name of the individual request being run.


    The unique guid that identifies the request being run.



The pm.sendRequest function allows sending HTTP/HTTPS requests asynchronously. Simply put, with asynchronous scripts, you can execute logic in the background if you have a heavy computational task or are sending multiple requests. Instead of waiting for a call to complete and blocking any next requests, you can designate a callback function and be notified when an underlying operation has finished.

Some things to know about pm.sendRequest():

  • The method accepts a collection SDK compliant request and a callback. The callback receives two arguments, an error (if any) and an SDK-compliant response. Refer to Collection SDK Documentation to view more information.
  • It can be used in the pre-request or the test script.
// example with a plain string URL
pm.sendRequest('', function (err, res) {
    if (err) {
    } else {
        pm.environment.set("variable_key", "new_value");

// Example with a full fledged SDK Request
const echoPostRequest = {
  url: '',
  method: 'POST',
  header: 'headername1:value1',
  body: {
    mode: 'raw',
    raw: JSON.stringify({ key: 'this is json' })
pm.sendRequest(echoPostRequest, function (err, res) {
  console.log(err ? err : res.json());

// example containing a test ** under the Tests tab only
pm.sendRequest('', function (err, res) {
  if (err) { console.log(err); }
  pm.test('response should be okay to process', function () {
    pm.expect(res)'code', 200);
    pm.expect(res)'status', 'OK');

Extended Reference:


pm.variables: Variable SDK Reference

In Postman, all variables conform to a specific hierarchy. All variables defined in the current iteration take precedence over the variables defined in the current environment, which overrides ones defined in the global scope. The order of precedence is Iteration Data < Environment < Collection < Global.

  • pm.variables.has(variableName:String):function → Boolean: Check if there is a local variable in the current scope.
  • pm.variables.get(variableName:String):function → *: Get the value of the local variable with the specified name.
  • pm.variables.set(variableName:String, variableValue:String"):function → void: Set a local variable with the given value.
  • pm.variables.replaceIn(variableName:String):function: Replaces the dynamic variable {{variable_name}} syntax with its actual resolved value.
  • pm.variables.toObject():function → Object: Returns an object containing all the variables in the local scope.

The variables defined in the individual scopes may also be accessed via pm.environment for the environment scope and pm.globals for the global scope.



  • Contains the name of the current environment.
  • pm.environment.has(variableName:String):function → Boolean: Check if the environment has a variable with the given name.
  • pm.environment.get(variableName:String):function → *: Get the variable with the given name in the currently selected environment.
  • pm.environment.set(variableName:String, variableValue:String):function: Sets the variable with the given name and value in the currently selected environment.
  • pm.environment.replaceIn(variableName:String):function: Replaces the dynamic variable {{variable_name}} syntax with its actual resolved value.
  • pm.environment.toObject():function → Object: Returns all the environment variables in the form of a single object.
  • pm.environment.unset(variableName:String):function: Remove a variable with the given name in the currently selected environment.
  • pm.environment.clear():function: Clears all variables in the currently selected environment.



  • pm.collectionVariables.has(variableName:String):function → Boolean: Check if there is a collection variable with the given name.
  • pm.collectionVariables.get(variableName:String):function → *: Returns the value of the collection variable with the given name.
  • pm.collectionVariables.set(variableName:String, variableValue:String):function: Sets a collection variable with given value.
  • pm.collectionVariables.replaceIn(variableName:String):function: Replaces the dynamic variable {{variable_name}} syntax with its actual resolved value.
  • pm.collectionVariables.toObject():function → Object: Returns a list of variables and their values in the form of an object.
  • pm.collectionVariables.unset(variableName:String):function: Clears the specified collection variable.
  • pm.collectionVariables.clear():function: Clear all the collection variables.



  • pm.globals.has(variableName:String):function → Boolean: Check if there is a global variable with the given name.
  • pm.globals.get(variableName:String):function → *: Returns the value of the global variable with the given name.
  • pm.globals.set(variableName:String, variableValue:String):function: Sets a global variable with given value.
  • pm.globals.replaceIn(variableName:String):function: Replaces the dynamic variable {{variable_name}} syntax with its actual resolved value.
  • pm.globals.toObject():function → Object: Returns a list of variables and their values in the form of an object.
  • pm.globals.unset(variableName:String):function: Clears the specified global variable.
  • pm.globals.clear():function: Clear all the global variables.


pm.request: Request SDK Reference

The request object inside pm is a representation of the request for which this script is being run. For a pre-request script, this is the request that is about to be sent and when in a test script, this is the representation of the request that was sent.

request contains information stored in the following structure:

  • pm.request.url:Url: Contains the URL to which the request is made.
  • pm.request.headers:HeaderList: Contains the list of headers for the current request.
  • pm.request.method:String The HTTP method of the sent request.
  • pm.request.body:RequestBody: Contains all the data related to the request body.
  • pm.request.headers.add(headerName:String):function: Adds a header with the specified name for the current request.
  • pm.request.headers.remove(headerName:String):function: Deletes the header with the specified name for the current request.
  • pm.request.headers.upsert({ key: headerName:String, value: headerValue:String}):function): Inserts a header name and header value as given to the list of headers for the current request (if the header does not exist, otherwise the already existing header is updated to the new value).

The following items are ONLY available in the test scripts.


pm.response: Response SDK Reference

Inside the test scripts, the pm.response object contains all information pertaining to the response that was received.

The response details are stored in the following format:

  • pm.response.code:Number
  • pm.response.status:String
  • pm.response.headers:HeaderList
  • pm.response.responseTime:Number
  • pm.response.responseSize:Number
  • pm.response.text():Function → String
  • pm.response.json():Function → Object



The iterationData object contains data from the data file provided during a collection run.

  • pm.iterationData.get(variableName:String):function → *: Returns a variable from the iteration data with the specified name.
  • pm.iterationData.toObject():function → Object: Returns the iteration data as an object.
  • pm.iterationData.addLayer(list: VariableList):function → void: Add a list of variables to iteration data.
  • pm.iterationData.clear():function → void: Clear all the data.
  • pm.iterationData.has(variableName: string):function → boolean: Checks if a variable with the specified name exists in iteration data.
  • pm.iterationData.set(key: string, value: any, type: string):function → void: Sets a variable, assigns it a value and type as specified.
  • pm.iterationData.syncVariablesFrom(object: {[key: string]: VariableDefinition}, track?: boolean, prune?: boolean):function → Object | Undefined: Get variables from an object with the name specified.
  • pm.iterationData.syncVariablesTo(object?: {[key: string]: VariableDefinition}):function → Object: Save the variables to an object with the name specified.
  • pm.iterationData.toJSON():function → *: Converts the iterationData object to JSON format.
  • pm.iterationData.unset(key: string):function → void: Un-assign the value given to a specified variable.
  • pm.iterationData.variables():function → Object: Return all the variables from the iterationData object.
  • static pm.iterationData.isVariableScope(object: any):function → boolean: Check if a specific variable is in scope.


pm.cookies: CookieList SDK Reference

The cookies object contains a list of cookies that are associated with the domain to which the request was made.

  • pm.cookies.has(cookieName:String):Function → Boolean

    Check whether a particular cookie (addressed by its name) exists for the requested domain.

  • pm.cookies.get(cookieName:String):Function → String

    Get the value of a particular cookie.

  • pm.cookies.toObject:Function → Object

    Get a copy of all cookies and their values in the form of an object. The cookies returned are the ones defined for the requested domain and path.


To enable programmatic access via the methods below, the cookie url must be whitelisted.

  • pm.cookies.jar():Function → Object

    Access the cookie jar object.

  • jar.set(URL:String, cookie name:String, cookie value:String, callback(error, cookie)):Function → Object

    Set a cookie using cookie name and value. One can also directly set the cookie by assigning cookie value to the cookie name within this function.

  • jar.set(URL:String, { name:String, value:String, httpOnly:Bool }, callback(error, cookie)):Function → Object

    Set a cookie using PostmanCookie or its compatible object.

  • jar.get(URL:String, token:String, callback (error, value)):Function → Object

    Gets a cookie from the cookie jar.

  • jar.getAll(URL:String, callback (error, cookies)):Function → Object

    Gets all the cookies from the cookie jar.

  • jar.unset(URL:String, token:String, callback(error)):Function → Object

    Unset a cookie.

  • jar.clear(URL:String, callback (error)):Function → Object

    Clear all cookies from the cookie jar.


Use pm.visualizer.set to specify a template to display response data in the visualizer.

pm.visualizer.set(layout:String, data:Object, options:Object):Function
  • layout required

  • data optional

    • Data to bind to the template and that you can access inside the template string
  • options optional

Example usage:

var template = `<p>{{}}</p>`;
pm.visualizer.set(template, {
    res: pm.response.json()


Use pm.getData to retrieve response data inside a visualization template string.


The callback function accepts two parameters:

Example usage:

pm.getData(function (error, data) {
  var value =;


pm.test(testName:String, specFunction:Function):Function

You can use this function to write test specifications inside either the Pre-request Script or Tests sandbox. Writing tests inside this function allows you to name the test accurately and this function also ensures the rest of the script is not blocked even if there are errors inside the function.

The following sample test checks that everything about a response is valid to proceed.

  pm.test("response should be okay to process", function () {;'');'error');

An optional done callback can be added to pm.test, to test asynchronous functions.

  pm.test('async test', function (done) {
    setTimeout(() => {
    }, 1500);
  • pm.test.index():Function → Number

    Get the total number tests from a specific location.


pm.expect(assertion:*):Function → Assertion

pm.expect is a generic assertion function. Underlying this is the ChaiJS expect BDD library. Using this library, it is easy to write tests where the syntax becomes readable.

This function is useful to deal with assertions of data from a response or variables. For assertion test examples using pm.expect, check out Assertion library examples

Response Assertion API available in the test scripts

  •, optionalValue:String)
  •, optionalValue:*)
  •, ajvOptions:Object)*

The properties inside the object allows you to easily assert a set of pre-defined rules.


    Checks 1XX status code


    Checks 2XX status code


    Checks 3XX status code


    Checks 4XX status code


    Checks 5XX


    Checks 4XX or 5XX


    Status code must be 200


    Status code must be 202


    Status code must be 400


    Status code must be 401


    Status code 403


    Status code of response is checked to be 404


    Checks whether response status code is 429

Dynamic variables

Postman uses the faker library to generate dummy data. You can generate random names, addresses, email addresses, and much more. You can use these pre-defined variables multiple times to return different values per request.

You can use these variables like any other variable in Postman. Their values are generated at the time of execution and their names start with a $ symbol e.g. $guid, $timestamp etc.

You can read the full list of dynamic variables in Postman.