Key takeaways
- The LoadFocus Chrome extension records your browsing session and turns it into a JMeter
.jmxscript, which you can run in the cloud or open in JMeter. - Strip analytics and third-party calls from a recording before running it.
- Parameterise the captured values; a replay of one session is not a load test.
- JMeter’s own HTTP(S) Test Script Recorder and a HAR converter are the alternatives when you cannot use an extension.
To record a JMeter test in Chrome, install the LoadFocus extension, start a recording, click through the flow you want to test and stop. The extension turns the captured browser traffic into a JMeter (.jmx) script that you can download, edit, or upload to LoadFocus to run from the cloud. The sections below cover the workflow, what to fix before you run a recording under load, and how to record without the extension.
What is the LoadFocus JMeter Chrome extension?
It is a free Chrome extension, listed on the Chrome Web Store as LoadFocus - JMeter Cloud Load Testing & Website Performance under Developer Tools. The listing (version 1.6.0, updated June 23, 2026, read October 2026) describes it as a way to “record JMeter tests while browsing, upload JMX files to the cloud, and run load tests with thousands of users”. It names these features:
- automatic JMeter script (JMX) generation from what you do on your website;
- cloud-based load tests from multiple locations, with no coding;
- live charts for response time, latency, hits per second and percentiles;
- uploads of JMeter files and downloads of results;
- reports with error rates, response times and percentile breakdowns.
The JMeter load testing page on loadfocus.com describes the same extension as a way to “record HTTP/S traffic and auto-generate JMeter (.jmx) scripts”. This post was first written in 2020, and the store name and parts of the interface have changed since. The screenshots below show the 2020 version, so labels in the current release may differ.
How do I record a JMeter test with the Chrome extension?
- Install it. Open the Chrome Web Store listing and add the extension to Chrome.
- Sign in to LoadFocus. Running a test in the cloud needs a LoadFocus account, and the LoadFocus site offers a free sign-up.
- Start a recording and browse. Open your site and go through the journey you want to test, for example the home page, a search and a product page. The extension captures the requests the browser makes.
- Stop the recording when the journey is done. In the 2020 version the popup showed a recording panel with a stop button and a pause button, and a field to name each test.
The recording panel in the 2020 version of the extension
Record one realistic user journey per script. A recording that wanders through twenty unrelated pages produces a test nobody can interpret.
Editing a recorded test
The 2020 version let you rename a recorded test, reorder requests by drag and drop, change a request’s URL, headers and method, and insert, duplicate or remove requests before exporting a .jmx or JSON file.
Editing a recorded test by inserting, duplicating or removing requests (2020 version)
I could not confirm the current editing screen from the store listing, so check what your version offers. Whatever the interface, you can always open the downloaded .jmx in JMeter and edit it there.
What should I fix in a recorded script before load testing?
A recording replays one session, so it needs work before it says anything about load:
- Remove third-party traffic. Analytics, ads, tag managers and chat widgets are recorded along with your own requests. Hitting someone else’s servers with load is unfair to them and distorts your numbers. Keep the requests to your own domains.
- Drop static assets you do not want to test. Images, CSS and fonts are often served by a CDN. Decide whether they belong in the test.
- Replace hard-coded values. The session cookie, CSRF token, username and search term from your recording will not work for the second virtual user. Parameterise them, and read test accounts from a file with a CSV Data Set Config.
- Check the order of elements. If you add assertions or timers, remember how JMeter executes elements.
- Add think time. A recording usually has no pauses, so a replayed script is much faster than a person.
- Run it once with one user and read the View Results Tree before you scale up. Every login or checkout that fails with one user will fail with a thousand.
How do I run the recorded test in the cloud?
Download the .jmx from the extension, or upload your edited file to LoadFocus. The JMeter load testing page says you can run an existing script unchanged from 25 cloud regions and set virtual users, duration and ramp-up for each run in the browser, without editing the script. CSV data files are uploaded together with the plan. See JMeter cloud load testing for the current plan limits, since test length and virtual user caps differ by plan.
Choosing cloud locations for a JMeter load test (2020 version)
Every run is kept so that you can reopen it, compare it with earlier runs or share it, according to the same page. The store listing also mentions live charts and reports with error rates, response times and percentiles.
A list of previous test runs (2020 version)
Can I record a JMeter script without the extension?
Yes, there are two common routes.
JMeter’s HTTP(S) Test Script Recorder. JMeter has its own proxy recorder. According to the JMeter manual (checked October 2026): open Templates in the menu bar and choose the Recording template, set your site’s host name in HTTP Request Defaults, click Start on the HTTP(S) Test Script Recorder, then point your browser’s proxy at localhost on port 8888 and browse your site. The recorded samplers appear under the Thread Group. For HTTPS, JMeter generates ApacheJMeterTemporaryRootCA.crt in JMETER_HOME/bin when the proxy starts, and you install that certificate in your browser.
A HAR file. Chrome, Fiddler and other tools can save a session as a HAR file (HTTP Archive), a JSON record of every request. LoadFocus has a HAR to JMeter converter that turns a HAR into a .jmx in the browser. Its page says cookies, tokens and auth headers become JMeter User Defined Variables rather than hard-coded values, and it has switches for images, CSS and JS and for requests to other sites. More on that route in importing cURL, HAR, Postman and OpenAPI into load tests.
The extension, JMeter’s recorder and a HAR all end in the same place: a .jmx file you clean up and run. For a first look at JMeter itself, see the introduction to Apache JMeter performance testing.
Frequently Asked Questions
How do I record a JMeter script?
Use a recorder that captures browser traffic and writes a .jmx file: the LoadFocus Chrome extension, JMeter’s own HTTP(S) Test Script Recorder (the Recording template), or a HAR file from your browser converted to JMeter. Whichever you use, clean the recording before you run it under load.
How do I record a JMeter script in the Chrome browser?
Install the LoadFocus extension from the Chrome Web Store, start a recording, browse through your journey and stop. The extension generates a JMeter script. To use JMeter’s own recorder instead, set Chrome’s proxy to localhost and the port of the recorder (8888 in the manual’s example) and install the JMeter root certificate for HTTPS.
How do I record a script in JMeter with Fiddler?
Capture the session in Fiddler, export it as a HAR file, and convert the HAR to a .jmx, for example with the HAR to JMeter converter on loadfocus.com. Then open the file in JMeter and check the samplers.
How do I capture logs in JMeter?
JMeter writes jmeter.log to the directory it was launched from, by default, and Options > Log Viewer shows it in the GUI. Logging is configured in log4j2.xml (also read from the launch directory by default), and the -j command-line option sets another log file. Add a View Results Tree listener to inspect individual requests and responses.
How do I capture an API response in JMeter?
Add a View Results Tree listener to read each response. To use a value from a response in a later request, add a JSON Extractor or Regular Expression Extractor as a child of the sampler. A Debug Sampler prints the current variables, which helps check what the extractors stored.
Sources
- Chrome Web Store, LoadFocus - JMeter Cloud Load Testing & Website Performance (version 1.6.0, read October 2026).
- Apache JMeter, Recording a test plan, step by step and Getting started: logging (checked October 2026).
- LoadFocus, JMeter load testing and HAR to JMeter (checked October 2026).
