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Postman API Testing Tutorial for Beginners
No Coding Needed
Postman API Testing Tutorial for Beginners
No Coding Needed
"If you're stepping into tech, you'll meet Postman sooner or later. Might as well make it now—and
make it simple."
Hey, it’s Sergii — founder of Codemify, where we take absolute beginners and turn them into real QA Engineers and SDETs.
Today, I’m going to walk you through Postman — one of the most popular API tools in the world.
Whether you’re just getting started in tech, switching careers, or trying to understand what the heck “API testing” even means, this guide will give you a clear, step-by-step intro to Postman — with zero code
required.
📺 Prefer video?
You can also watch this full tutorial (with screen walkthrough) on our Codemify YouTube Channel.
Make sure to subscribe — we release practical tech tutorials every week to help you break into tech faster and smarter.
Make sure to subscribe — we release practical tech tutorials every week to help you break into tech faster and smarter.
🛠 What Is Postman?
Postman is like your Swiss Army knife for working with APIs. It helps you send requests, get responses,
and verify what’s happening behind the scenes in any app that uses APIs (so... basically everything).
Even if you’re not a developer — maybe you’re a QA Engineer, Product Manager, or just tech-curious — you will touch APIs. And Postman makes it way easier.
and verify what’s happening behind the scenes in any app that uses APIs (so... basically everything).
Even if you’re not a developer — maybe you’re a QA Engineer, Product Manager, or just tech-curious — you will touch APIs. And Postman makes it way easier.
Step 1: Installing Postman
- Go to postman.com/downloads
- Choose your OS (Mac or Windows)
- Download the app and follow the instructions
- Create a free account (or sign in if you already have one)
Go to Apple > System Settings > About.
🛍 Step 2: Welcome to Postman – The Interface
Once you're in:
- You'll see Collections on the left — think of them as folders that store API requests.
- Click + New Collection and call it something like My Test APIs .
🔍 Step 3: Make Your First API Request
Terminal & Bash Basics: Navigate directories, manage files, and understand command-line operations.
Version Control with Git & GitHub: Learn to clone repositories, commit changes, and handle branches.
Development Tools:
Version Control with Git & GitHub: Learn to clone repositories, commit changes, and handle branches.
Development Tools:
- VS Code: Set up and configure for efficient coding.
- Node.js & NPM: Install and manage packages essential for automation frameworks.
🖥️ Step 2: Understand Web Technologies
Let’s grab a free API from random-data-api.com:
2. In Postman, click + New Request , paste the URL, and make sure the method is GET.
3. Hit Send
Boom. You just made your first API call.
- Copy this:
https://random-data-api.com/api/v2/users
2. In Postman, click + New Request , paste the URL, and make sure the method is GET.
3. Hit Send
Boom. You just made your first API call.
What Just Happened?
You sent a GET request to a server asking, “Hey, give me some data.”
The server responded with structured info like:
The server responded with structured info like:
{
"id": 101,
"first_name": "Sergii",
"last_name": "Khromchenko"
}Always check:
Status Code = 200 (OK)
Response Time = fast
Response Body = correct format and values
Status Code = 200 (OK)
Response Time = fast
Response Body = correct format and values
Understanding the API URL
Example:
https://random-data-api.com/api/v2/users?beer_type=lighthttps://random-data-api.com → Base URL
/api/v2/users → Path
?beer_type=light → Query Parameter
You can use query params to filter or customize what the API gives you.
/api/v2/users → Path
?beer_type=light → Query Parameter
You can use query params to filter or customize what the API gives you.
Authorization & Headers (Quick Look)
If you're testing private APIs (like login requests), you'll need to deal with:
Postman helps you manage all of this, and your developer will usually tell you exactly what to include.
- Authorization Tokens
- Header fields like Content-Type , Accept , etc.
Postman helps you manage all of this, and your developer will usually tell you exactly what to include.
Sending Data with POST
- When you want to create data (like a new user), you’ll use a POST request.
- Go to the Body tab, select raw > JSON, and enter:
{
"name": "Sergii",
"age": "young"
}Click Send to create the entry.
Uploading Files
Switch the body type to form-data, choose a key like image , and upload a file directly from your machine.
Postman makes file testing super easy.
Postman makes file testing super easy.
Automating Tests in Postman (The Easy Way)
Even if you don’t code yet, you can still automate basic checks.
Example test (status code = 200):
Example test (status code = 200):
pm.test("Status code is 200", function () {
pm.response.to.have.status(200);
});Click the three dots next to your collection > Run Collection, and you’ll see if your test passes or fails
instantly. This is the foundation of API test automation.
instantly. This is the foundation of API test automation.
📊 Ready for More?
This was the beginner's crash course — but there's so much more you can do with Postman:
But let’s be real — learning this solo can get overwhelming.
🎓 Want to try QA for real — before committing?
We created a 1-week intro course designed for people exactly like you. Whether you want to test out Manual QA or QA Automation, we’ll guide you through it — step by step — with real support and real tasks.
👉 Just $20, no experience required, and you’ll know by the end if tech is for you.
Choose your track and get started here:
https://www.codemify.com/intro
- Auth flows
- Chained requests
- Advanced automation
- Mock servers
- Real-world QA testing pipelines
But let’s be real — learning this solo can get overwhelming.
🎓 Want to try QA for real — before committing?
We created a 1-week intro course designed for people exactly like you. Whether you want to test out Manual QA or QA Automation, we’ll guide you through it — step by step — with real support and real tasks.
👉 Just $20, no experience required, and you’ll know by the end if tech is for you.
Choose your track and get started here:
https://www.codemify.com/intro
📺 Still Here? Watch the Full Tutorial on YouTube
Watch the full Postman tutorial on YouTube here — and hit subscribe so you never miss new tech
tutorials from Codemify.
Whether you want to break into tech, level up your QA game, or just understand what your dev team is talking about — we got you.
See you in the next tutorial.
Let’s make tech simple — and profitable — for you.
— Sergii
Founder of Codemify
Follow us on YouTube | Join the Bootcamp
tutorials from Codemify.
Whether you want to break into tech, level up your QA game, or just understand what your dev team is talking about — we got you.
See you in the next tutorial.
Let’s make tech simple — and profitable — for you.
— Sergii
Founder of Codemify
Follow us on YouTube | Join the Bootcamp
Schedule a FREE 15-minute consultation with Sergii to discuss your testing career and job opportunities.
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Limited slots are available!
We help ambitious people to get into Tech with no prior experience.