Automated Correlation and Parameterization

The Problem

You just recorded a user flow in JMeter. The script replays correctly once. Then, you run it with 10 users and half of them start getting 401 Unauthorized or 404 Not Found errors.

The problem is almost always correlation; the script contains values that were dynamic during recording (session tokens, CSRF tokens, product IDs, timestamps, generated UUIDs) but are now hardcoded. The second request that depends on a token from the first request is sending the token from the recording session, which has expired already or never existed for the other virtual users.

Finding and fixing all of these by hand in a long, recorded script is tedious work. AI can do most of it for you.