Tools for performance testers
Free, no signup, no account. Size a load model, convert a script between tools, check what a script is about to leak, or read a results file — each one runs in your own browser.
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Load Model Calculator
Calculate virtual users and load profiles for steady-state, spike and stress tests. Outputs JMeter, k6 and Gatling config.
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Script Converter
Convert between JMeter, k6 and Gatling in any direction, and see which parts of your script need manual work. Runs in your browser — nothing is uploaded.
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Script Scanner
Find credentials, personal data and production hostnames in a script or its CSV feeds before you share it. Runs in your browser; the report shows where, never what.
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Report Viewer
Open a JMeter, k6 or Gatling results file and read the report — percentiles, Apdex, errors, per-endpoint timings. Runs in your browser, and can sanitise the report before you share it.
Why nothing is uploaded
The tools that take a file — the converter, the scanner and the report viewer — are served from tools.martkos-it.co.uk, an origin that serves files and accepts nothing. Its Content-Security-Policy sets connect-src 'self', so the browser itself would block an attempt to send your script anywhere, whatever the page tried to do. You can check that in devtools rather than take our word for it.
The Load Model Calculator lives on this site and needs no such promise: you give it a handful of numbers, and there is nothing to protect.
When the free tool runs out
The browser tools solve small jobs outright and show you the size of the ones they cannot. When a conversion needs correlation, or a report needs to gate a build, the paid tools pick up where these stop.
Looking for something specific?
The same tools, written up for the job you came here to do — what they handle, what they will not do, and how to get a usable result out the other side.
Convert a JMeter script to k6
Convert a JMeter .jmx to a runnable k6 script free in your browser, nothing uploaded. Grafana archived its own jmeter-to-k6 in 2022; this one is maintained.
Read the guideTurn a HAR recording into a JMeter test plan
Convert a Chrome HAR to a runnable JMeter .jmx — free, no signup, and the file never leaves your browser. Other converters ask you to upload it.
Read the guideOpen a .jtl results file and read the report
Open a JMeter .jtl, k6 JSON or Gatling simulation.log in your browser and read the report — percentiles, Apdex, errors, per-endpoint timings. Nothing uploaded.
Read the guide