# Gatling vs k6: Load Testing Tools Compared (2026) > Gatling vs k6 compared: scripting languages, reports, efficiency, and paid cloud options, with fact-based advice on which load testing tool fits your team. Source: https://loadster.com/compare/gatling-vs-k6/ As far as open source load testing tools go, Gatling and k6 are usually on a developer's shortlist: both are code-first, protocol-level, CI-friendly open source tools with commercial clouds on top. The stereotype says Gatling is for JVM shops and k6 is for JavaScript shops — and this is still somewhat true, although Gatling's newer SDKs have blurred the language line. Here's a fact-based comparison from the team behind [Loadster](https://loadster.com/). Although our platform also does load testing, we aren't affiliated with either of these tools so we'll tell it straight. ## Gatling vs k6 at a Glance | | **Gatling** | **k6** | |---|---|---| | **Tool type** | Open source JVM load testing tool | Open source CLI load testing tool | | **License/pricing** | Apache 2.0; free (Gatling Enterprise for managed runs) | AGPL-3.0; free (Grafana Cloud k6 for managed runs) | | **Script style** | Code DSL: Java, Scala, Kotlin, JavaScript, or TypeScript | JavaScript code, run by a Go engine | | **Protocol testing** | HTTP-focused; JMS and more in the ecosystem | HTTP, WebSockets, gRPC; more via xk6 extensions | | **Browser testing** | Not supported | Browser module (Chromium), small scale | | **Playwright** | Not supported | Playwright-inspired API, not Playwright itself | | **Load generation** | Your machines; Gatling Enterprise for distributed runs | Your machines; k6-operator on Kubernetes; Grafana Cloud k6 | | **Reporting** | Polished HTML reports out of the box | CLI summary; dashboards via Grafana or Cloud k6 | | **Site monitoring** | Not included | Not included (separate Grafana products) | | **CI/CD Tooling** | Good: assertions, CI plugins | First-class: single binary, thresholds, exit codes | | **Learning curve** | Comfortable for JVM developers; JS SDK lowers the bar | Comfortable for JavaScript developers | | **Migration** | No importer (rebuild via recorder) | Imports into Loadster | ## Where Gatling Shines Gatling's standout feature is reporting: every run produces a polished, self-contained HTML report with percentile charts and per-request detail, with no dashboard assembly required — the best out-of-the-box reporting in open source load testing. The DSL is expressive for modeling complex user journeys, and modern Gatling offers SDKs in Java, Scala, Kotlin, JavaScript, and TypeScript[^1], so teams outside the Scala world are no longer excluded. For JVM shops especially, Gatling slots into existing build tooling (Maven, Gradle, SBT) like any other dependency. ## Where k6 Shines k6 is leaner to operate and stronger in CI. It ships as a single binary with pass/fail thresholds and exit codes built in, so "performance test as build step" takes minutes to wire into any pipeline. Its Go engine[^2] is highly efficient per machine, the documentation is excellent, and the xk6 extension ecosystem covers protocols beyond the HTTP/WebSockets/gRPC core. If your team writes JavaScript and your dashboards already live in Grafana, k6 is the path of least resistance. ## Scripting Differences Between Gatling and k6 Both are code-first; the difference is runtime and idiom. Gatling simulations are built with a fluent DSL (scenarios, injections, assertions) compiled and run on the JVM, which means JVM tooling, JVM dependencies, and JVM startup characteristics. k6 scripts are plain JavaScript files executed by k6's own Go runtime — not Node.js, so npm packages generally don't work[^3], but the runtime is what delivers k6's efficiency. Neither tool has a meaningful GUI or recorder-first workflow: in both cases, engineers write and maintain the scripts, and non-developers stay outside the loop. ## Generating Load at Scale A single machine goes further with either tool than with older thread-based tools, and k6 generally squeezes the most from each core. Past one machine, both push you toward their commercial arms: Gatling Enterprise adds managed distributed execution, dashboards, and team features[^1], while k6 offers the self-managed k6-operator on Kubernetes or Grafana Cloud k6 priced by virtual user hours. Neither does real browser load testing at meaningful scale — Gatling has no browser mode at all, and even Grafana Cloud k6 caps browser VUs at 1,000 per test[^4]. ## Which Load Testing Tool Should You Choose? Seriously consider **Gatling** if: * Your team lives on the JVM, or wants SDK choices across five languages * Polished reports out of the box matter more than dashboard flexibility * You're modeling complex user journeys with an expressive DSL Seriously consider **k6** if: * Your team writes JavaScript and wants the leanest CI integration * Per-machine efficiency and a single-binary workflow appeal to you * You already use Grafana for dashboards and observability ## A Third Option: a Cloud Load Testing Platform If what you're actually weighing is who runs the infrastructure and how results get shared — or you need real browser load testing, which neither tool offers at scale — the answer may be one of the cloud platforms. Ours is [Loadster](https://loadster.com/), and some of its strong points include fully managed load generation across 32 cloud regions, real Chrome browsers at scale alongside protocol-level bots (Loadster customers have run more than 170,000 concurrent browsers in a single test, and Protocol Bot counts go well into the millions), shareable reports and site monitoring built in, and a [k6 importer](https://loadster.com/changelog/2026-06/) if that's where your scripts live today. There's no Gatling importer, but the browser-extension recorder rebuilds web scenarios quickly. The free trial fuel is enough to run a few tests with no credit card required. If you'd like to weigh more options than ours, our [load testing tools guide](https://loadster.com/compare/load-testing-tools/) ranks the whole field, cloud platforms and open source tools alike. ## Frequently Asked Questions ### Is Gatling or k6 better for load testing? Both are excellent code-first protocol tools, so it usually comes down to ecosystem. k6 fits JavaScript-first teams and CI pipelines, with a single binary and thresholds built in. Gatling fits JVM shops, offers SDKs in Java, Scala, Kotlin, JavaScript, and TypeScript, and produces the best out-of-the-box HTML reports of the open source field. Neither does real browser load testing at meaningful scale. ### Does Gatling support JavaScript like k6? Yes — modern Gatling offers SDKs for Java, JavaScript, TypeScript, Scala, and Kotlin, so the old 'Gatling means Scala' objection no longer holds. The difference is runtime: Gatling runs on the JVM while k6 runs its JavaScript on a purpose-built Go engine, which affects tooling, dependencies, and per-machine efficiency more than syntax. ### Do Gatling and k6 have managed cloud options? Yes, both follow the open-core model. Gatling Enterprise adds a web UI, managed distributed execution, dashboards, and team features on top of the open source tool. Grafana Cloud k6 runs k6 scripts on managed infrastructure priced by virtual user hours. In both cases large-scale testing stops being free. ### Can I convert Gatling scripts to k6 or vice versa? No converter exists in either direction — the scripting models are different enough that switching means rewriting. If you're switching because of infrastructure or reporting rather than the language, Loadster imports k6 scripts directly (though not Gatling simulations), and its recorder rebuilds web scenarios quickly regardless of where they started. For a deeper look at the k6 side, see [Loadster vs k6](https://loadster.com/compare/loadster-vs-k6/). [^1]: [Gatling's documentation](https://docs.gatling.io/) describes test scenarios "defined as code using expressive SDKs for Java, JavaScript, TypeScript, Scala, or Kotlin," with Gatling Enterprise adding a web UI, managed runs, and dashboards. [^2]: [Grafana's k6 page](https://grafana.com/oss/k6/) describes k6 as having "a scriptable engine written in Go" with tests authored in JavaScript or TypeScript. [^3]: [Grafana's k6 module docs](https://grafana.com/docs/k6/latest/using-k6/modules/) explain that k6 uses browser-like module resolution and does not support Node.js module resolution. [^4]: [Grafana Cloud k6 limits and quotas](https://grafana.com/docs/grafana-cloud/testing/k6/projects-and-users/limits-and-quotas/) list a maximum of 1,000 browser VUs per test on paid plans.