Your First Real-World k6 Test

Now that we have complete setup of K6 ready following previous Introduction & Getting Started with k6 post, let’s create a practical k6 script that simulates an actual flow.

We will simulate:

1. visiting a page.
2. loading product data.
3. performing an action.

This scenario mirrors the real world traffic and we can expand later by adding more test features.

Table of contents

Project Setup

1. Create a Working Directory

This directory will store all blog-series scripts:

mkdir k6-course
cd k6-course

2. If you are using VS Code, I recommend installing k6 for Visual Studio Code plugin.

3. Create a file real-world-test.js in k6-course directory:

The Flow We’re Going to Simulate

Instead of fake endpoints, this test uses a realistic sequence:

• Load the homepage
• Fetch a product list
• View a single product
• Perform a POST action (e.g., add to cart)

This pattern resembles real SaaS interaction as uur script will hit multiple endpoints, validates each step and mirror actual user behavior patterns.

Code Walkthrough

Imports

import http from "k6/http";
import { sleep, check } from "k6";

• http provides functions to send HTTP requests (get, post, put, del, etc.).
• check evaluates test conditions on responses (status codes, response body) and records pass/fail metrics.
• sleep pauses a VU for a number of seconds to simulate real world user behaviour.

Test Options

export const options = {
  vus: 5,
  duration: "30s",
};

• vus: virtual users → “how many simultaneous users to simulate”
• duration: total runtime → avoids running indefinitely

This runs 5 users for 30 seconds, a small load but enough to reveal basic performance patterns.

Default function — the VU behavior

export default function () { ... } is the function every virtual user executes repeatedly for the test duration.

Homepage Request

let home = http.get("https://fakeloadtest.com");
check(home, {
  "homepage loaded": (r) => r.status === 200,
});

• Sends a GET request
• r.status returns the status code
• We can use (r) => r.status === 200 check to ensure the endpoint responds correctly with 200 OK status code

Fetch Product List

let products = http.get("https://fakeloadtest.com/api/products/");
check(products, {
  "Get Products": (r) => r.status === 200,
});
const list = products.json();

• Fetches a list of items (in this case, public products)
• check to ensure the endpoint responds correctly with 200 OK status code
• const list = products.json() Converts the response body into a JavaScript array

View Product Details

const productId = list[0].id;
let product = http.get(
  `https://fakeloadtest.com/api/products/${productId}/`
);
check(product, {
  "Get Product Detail": (r) => r.status === 200,
});

• list[0].id Picks one product (the first one)
• Fetches its detail page
• check to ensure the endpoint responds correctly with 200 OK status code

Perform a POST Action

let action = http.post(`https://fakeloadtest.com/api/products/add-to-cart`, {
  product_id: productId,
});
check(action, {
  "Product Added To Cart": (r) => r.status === 200,
});

• Simulates an action like “add to cart”, “save item”, etc.
• Uses httpbin.org as a safe echo endpoint
• Confirms server accepts POST requests

Adding Pacing Time

sleep(1);

• Pacing time helps mimic real world user pacing

Putting it all together

import http from "k6/http";
import { sleep, check } from "k6";

export const options = {
  vus: 5,
  duration: "30s",
};

export default function () {
  // Step 1: Homepage
  let home = http.get("https://fakeloadtest.com");
  check(home, {
    "homepage loaded": (r) => r.status === 200,
  });

  // Step 2: Product List
  let products = http.get("https://fakeloadtest.com/api/products/");
  check(products, {
    "Get Products": (r) => r.status === 200,
  });
  const list = products.json();

  if (!list.length) return;

  // Step 3: Pick a product and view details
  const productId = list[0].id;
  let product = http.get(
    `https://fakeloadtest.com/api/products/${productId}/`
  );
  check(product, {
    "Get Product Detail": (r) => r.status === 200,
  });


  // Step 4: Add product to cart
  let action = http.post(`https://fakeloadtest.com/api/products/add-to-cart`, {
    product_id: productId,
  });
  check(action, {
    "Product Added To Cart": (r) => r.status === 200,
  });
  sleep(1);
}
k6-course/real-world-test.js

Now Run:

k6 run real-world-test.js

You should see success/failure for each check, plus useful metrics like::

• iteration duration
• request latency
• HTTP timings
• throughput

Practice Exercise

Extend this real-world flow by adding another API call and another check.

1. After the POST request, add a DELETE request to simulate “remove from cart”.
2. Save the response body to a variable.
3. Add a new check verifying:

• status is not 400
• response contains “json” field

Run this test again and compare metrics to the previous run.