Making REST API Calls with Postman

Why Postman and How to Get it?

• Quickly test APIs in GUI
• Save APIs into Collection for reuse
• Manage multiple environment
• Auto generate code from API calls
• Standalone application or Chrome plugin


Sending an API Request

• Choose method
• Enter URI
• Configure headers and authentication
• Provide data
• Send and verify status
• Enter into the URL field and click Send


• You see Status: 200 OK in the response row in Postman and you should get this JSON back as a response body, with your system's value for postman-token

    "args": {
        "aaaUser": {
            "attributes": {
    "headers": {
        "accept-encoding""gzip, deflate",



Working with API Collections

• With an API collection you store and group API requests into folders
• Use a Postman collection when you want to use the same variable across many requests


Using Environments and Variables

• Use a Postman environment when you want to protect credentials or an API endpoint

Variables Make Requests Reusable and Flexible

• Never good to hardcode details
• What if you want to connect to different host?
• What if credentials change?
• Variable References

{{ apic }}          # host
{{ username }}
{{ password }}


Managing Environments

• To create an environment, click the Settings (gear) icon in the right-hand side of Postman and choose Manage Environments.
• Create any number of environment needed
• Change between environments with drop down list
• Add as many variables as needed
• Reference anywhere with {{ variable name }} syntax

Setting Environment Variables Dynamically

• What about when info from one request is needed from another?
• Manually copying / pasting slow and error prone
• Manually updating environment variables is slow and awkward


• To use a variable, add double curly brackets {{variable}} around the value you want to change within the Postman interface
• You can store endpoints you use frequently and then change between environments with a drop-down list

Tests Enable Dynamic Environment Variables

• Each API request offers both pre and post actions
◇ Pre → Pre-request script
◇ Post → Tests
• Written in JavaScript


Using Postman to Generate Code!

You'll eventually want to write some code...

• ** Note ** Maximize your Postman Window to use this feature. Otherwise, you can't see command options available
• Postman great for testing and validating APIs
• But it's about atomic actons
• Business Logic, stringing APIs together, etc all need code
• Jumpstart with auto-generated code by Postman
• Many, many options for languages available

Full API Request to Code!

• Headers, payload data and URI all included
• Environment variables are translated
• Great starting point, but expect to edit and update