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5+ Ways to Debug a JMeter Script

If you ever have designed JMeter scripts, I bet you have been stuck at least one time figuring out why a Json Extractor is not working. Guess what? I've been there!

Do you know why best JMeter Performance Engineers almost always find solutions to their problems? They master JMeter Script Debugging.

That's why I have compiled the best JMeter Debug Practices into a huge single post covering:

  • How to use the Debug Sampler (and get the best out of it),
  • Leverage View Results Tree secret features: Regex Tester, Json Path Tester and Regex Tester (and never fail a variable correlation again),
  • How to use Dummy Sampler to generate fake requests to try things (without hitting a real server!),
  • And many other tips like How to view JMeter Logs.

Let's see them in greater details.

How to Record a Scenario with JMeter

So you started designing a scenario using JMeter manually. After working a while on this grueling task, you start wondering: Isn't there a way to record browser interactions with JMeter?

The short answer is yes! Jmeter's HTTP(s) Test Script Recorder is exactly designed to record test scenarios.

This tutorial teaches you:

  • What a Proxy is and how the recorder works,
  • How to intercept and record HTTP Requests automatically while using your web browser,
  • How to record SSL-secured (https requests),
  • How to configure Proxy Settings with Google Chrome and Firefox,
  • And the most important part: recording the script!

You'll see there are a few caveats but everything is well explained.

We assume you already:

I know how impatient you are, so let's start now!

JMeter Basic Authentication Explained

You're often confronted with web application which requires user to authenticate. Basic Access Authentication is one of the most simple authentication method:

  1. Client includes an HTTP Header like Authorization: Basic dXNlcm5hbWU6cGFzc3dvcmQ=, with Base64 encoded username and password (username:password equals dXNlcm5hbWU6cGFzc3dvcmQ= in Base64) in each request,
  2. Server grants access whenever the provided username and password are correct.

This guide will teach you 3 different ways to handle basic authentication:

Let's see dive into JMeter with examples you can use yourself!

Rest API Testing with JMeter (Step by Step Guide)

I'm sure you're here because you need to load test a Json Rest API. It's not a surprise since Rest API are increasingly popular these days.

That's the purpose of this guide: help you load test a Json Rest API through a concrete example, OctoPerf's Json Rest API.

And this guide will completely get you through the following knowledge:

No theory here, only practice: everything is based on a realistic Rest API (not a dummy example). You can download the sample JMX while following the tutorial.

Ready to learn? Let's go!

JMeter Assertions: The Ultimate Guide

Whether you want to:

  • Check if the server response contains a specific string,
  • Or Verify the server returned an HTTP 200 OK,
  • Or check the value of a json field (using JsonPath like $.store..price).

Assertions are the way to go.

The problem is: you don't know how to get started. And the number of available assertions is overhelming. No worries!

This ultimate guide on JMeter Assertion explores every single assertion type through comprehensive examples. You'll know when and how to use each kind of assertion wisely. Once you've read this guide, assertions won't have any secrets for you anymore! Let's go.