Authors Gatling simulations in Java / Kotlin / Scala (or JS / TS) using the Simulation class plus http() / scenario() / exec() DSL builders, ramps virtual users via injectOpen (arrival rate) or injectClosed (concurrent count), runs via Maven / Gradle / sbt with the Gatling plugin, and gates CI on assertions defined in setUp(). Use when the project is on the JVM and the team prefers code-first load tests over JMeter's XML or k6's JavaScript-only authoring.