Skip to content

JMeter & k6 alternatives

Six load testing tools compared: k6, JMeter, Gatling, Locust, Artillery and VoltTest

The right load testing tool is mostly decided by the language your team already writes and the protocols you need to test. JMeter covers the most protocols, k6 and Artillery suit JavaScript teams, Gatling suits the JVM, Locust suits Python, and VoltTest suits PHP. None of them is the best choice for everyone.

Disclosure: we build VoltTest. We've kept performance numbers off this page because we haven't benchmarked all six tools under the same conditions, and the VoltTest section says plainly where it is the wrong choice.

The short answer

Start from your team's language and your hardest requirement.

JavaScript or TypeScript team

k6

Clean scripting API, CI thresholds, Grafana integration

JDBC, JMS, LDAP or air-gapped

Apache JMeter

Widest protocol list, fully self-hosted

Java, Kotlin or Scala team

Gatling

Code-first on the JVM with shareable HTML reports

Python team

Locust

Plain Python, built-in distributed mode, MIT license

Node.js team or real-browser tests

Artillery

YAML plus JavaScript, Playwright integration

PHP or Laravel team

VoltTest

Tests in PHP, local runs, managed multi-region cloud

Side by side

Licenses and protocols as documented by each project.

k6
Scripting
JavaScript / TypeScript
License
AGPL-3.0
Run it yourself
Single binary; distributed runs via the k6 Operator on Kubernetes
Managed option
Grafana Cloud k6
Protocols
HTTP/1.1, HTTP/2, WebSocket, gRPC; more through xk6 extensions
Best for
JavaScript and TypeScript teams, especially those already on Grafana
Apache JMeter
Scripting
GUI test plans saved as XML (.jmx); Groovy for custom logic
License
Apache 2.0
Run it yourself
Desktop GUI plus CLI mode; distributed runs on primary–worker nodes you set up
Managed option
Third-party services that run .jmx plans (for example BlazeMeter or Azure Load Testing)
Protocols
HTTP, JDBC, JMS, FTP, LDAP, SMTP, TCP and more; plugins add others
Best for
QA teams with existing test plans or non-HTTP protocols to test
Gatling
Scripting
Java, Kotlin, Scala, JavaScript or TypeScript SDKs
License
Apache 2.0 (Community Edition); gRPC, MQTT and GraphQL under a separate component license
Run it yourself
Community Edition generates load from your own machine
Managed option
Gatling Enterprise (managed or private load generators)
Protocols
HTTP/1.1, HTTP/2, WebSocket, SSE, JMS; gRPC, MQTT and GraphQL capped in Community
Best for
JVM or TypeScript teams that need shareable reports
Locust
Scripting
Python
License
MIT
Run it yourself
CLI or web UI; built-in distributed mode across machines
Managed option
Third-party services that run Locust scripts (for example Azure Load Testing)
Protocols
HTTP out of the box; any protocol through a custom Python client
Best for
Python teams who want tests as ordinary code
Artillery
Scripting
YAML scenarios with JavaScript or TypeScript hooks
License
MPL 2.0 for most of the codebase; Azure modules under BSL
Run it yourself
Node.js CLI; scale out on AWS Lambda or Fargate in your own AWS account
Managed option
Artillery Cloud for dashboards and reports (free plan and paid plans)
Protocols
HTTP, WebSocket, Socket.IO, gRPC, Kinesis, GraphQL
Best for
Node.js teams, and anyone mixing API load with real-browser tests
VoltTest
Scripting
PHP SDK; Laravel package with Artisan commands
License
Proprietary engine and platform; PHP SDK and Laravel package are open source
Run it yourself
Headless engine runs locally with no account
Managed option
VoltTest Cloud, with load from 24 AWS regions, several per run
Protocols
HTTP/HTTPS only
Best for
PHP and Laravel teams load testing web apps and APIs

Each tool, honestly

What each one is best at, where it falls short, and who should pick it.

  1. 01

    k6

    Grafana Labs

    Tests as JavaScript code, built for CI and the Grafana stack

    Best at

    • Clean scripting API with checks and thresholds that can fail a CI job
    • HTTP/2, WebSocket and gRPC built in, plus a browser module for real-browser tests
    • Native outputs to Prometheus, InfluxDB and Grafana dashboards
    • xk6 extensions add protocols and outputs the core does not ship

    Falls short

    • Scripts run in k6’s own JavaScript runtime, not Node.js, so many npm packages need bundling or do not work
    • Self-hosted distributed tests mean running Kubernetes and the k6 Operator
    • AGPL-3.0 is a license some legal teams review more carefully than Apache 2.0 or MIT

    Choose k6 if…

    • Your team writes JavaScript or TypeScript
    • You already run Grafana, Prometheus or InfluxDB
    • You need WebSocket or gRPC load tests
    k6 website VoltTest vs k6
  2. 02

    Apache JMeter

    Apache Software Foundation

    The long-standing GUI tool with the widest protocol coverage

    Best at

    • Broadest built-in protocol list of any tool here, including JDBC, JMS and LDAP
    • HTTP(S) Test Script Recorder and a GUI for people who prefer not to write code
    • Large plugin ecosystem and a deep pool of engineers who already know it
    • Free and fully self-hosted, including air-gapped networks

    Falls short

    • Test plans are XML, which is hard to review in a pull request
    • Each virtual user is a JVM thread, so high concurrency usually means more load-generator machines and heap tuning
    • Distributed mode is manual; the GUI is meant for building plans, and load runs belong in CLI mode

    Choose Apache JMeter if…

    • You must test JDBC, JMS, LDAP or other non-HTTP protocols directly
    • Your environment is on-premises or air-gapped
    • You already maintain a library of .jmx plans
    Apache JMeter website VoltTest vs JMeter
  3. 03

    Gatling

    Gatling Corp

    Code-first load testing with polished HTML reports

    Best at

    • Asynchronous engine rather than a thread per virtual user
    • Detailed HTML report after every run, ready to share with stakeholders
    • Five language SDKs, so it is no longer a Scala-only or JVM-only tool
    • Correlation and feeders are first class, so multi-step flows are straightforward

    Falls short

    • Community Edition runs from one machine; managed or multi-node load generation is Gatling Enterprise
    • gRPC, MQTT and GraphQL are limited to 5 users and 5-minute tests in Community Edition
    • Needs a Maven, Gradle, sbt or npm project to get started

    Choose Gatling if…

    • Your team works in Java, Kotlin, Scala or TypeScript
    • Reports go in front of clients or managers
    • You are moving off JMeter but want to stay on the JVM
    Gatling website
  4. 04

    Locust

    Open-source community

    Load tests as plain Python classes

    Best at

    • Tests are ordinary Python, so any Python library is available
    • Distributed mode across several machines is built in
    • Live web UI where you can change the user count mid-run, or headless for CI
    • MIT license, the most permissive here

    Falls short

    • Each worker process uses one CPU core, so large tests mean running many worker processes
    • Non-HTTP protocols mean writing and maintaining your own client
    • No built-in long-term result history; you export stats or ship them elsewhere

    Choose Locust if…

    • Your team writes Python
    • You need to load test a custom protocol and are happy to write the client
    • You want a permissive license and a simple self-hosted setup
    Locust website
  5. 05

    Artillery

    Artillery

    YAML-first, Node.js-native, with Playwright for real browsers

    Best at

    • Simple tests are a short YAML file; complex logic drops into JavaScript hooks
    • Playwright integration runs load tests in real headless browsers
    • Distributed runs on AWS Lambda or Fargate without managing servers
    • Socket.IO and WebSocket support for real-time apps

    Falls short

    • Complex flows outgrow YAML and end up split between YAML and JavaScript
    • Team dashboards and report history live in Artillery Cloud, which is paid beyond its free plan
    • The Azure modules are under BSL, not MPL 2.0

    Choose Artillery if…

    • Your team works in Node.js
    • You need real-browser load tests with Playwright
    • You load test Socket.IO or WebSocket services
    Artillery website
  6. 06

    VoltTest

    VoltTest (that’s us)

    Load tests written in PHP, run locally or on managed cloud

    Best at

    • Tests are PHP, versioned in your repository next to the application
    • Laravel package: Artisan commands, scaffolding from your route table, PHPUnit assertions that fail a build on a p95 regression
    • Local runs need no account; one switch moves the same test to managed cloud
    • Managed cloud across 24 AWS regions with a live dashboard, and a free plan with no credit card

    Not the right choice when

    • HTTP/HTTPS only: no WebSocket, gRPC or HTTP/2
    • No real-browser testing
    • The engine is proprietary and there is no self-hosted dashboard, so air-gapped teams should look elsewhere
    • No GUI recorder, and a younger, smaller community than every other tool here

    Choose VoltTest if…

    • Your application and team are PHP or Laravel
    • You want load tests in the same language and repository as the app
    • You want managed multi-region load without running load generators
    Start free All features

Replacing JMeter or k6

Why you're leaving narrows the list quickly.

Moving off JMeter

  • You want code instead of XML but to stay on the JVMGatling →
  • Your developers write JavaScript or TypeScriptk6 →
  • Your developers write PythonLocust →
  • Your developers write PHP or LaravelVoltTest →

Moving off k6

Sometimes the answer is to stay. If JMeter is testing JDBC or JMS for you, or k6 is wired into Grafana alerts your team relies on, switching costs more than it saves. Rewriting tests is the expensive part of any move, so migrate one critical flow first and compare results before porting the rest.

Common questions

What is the best JMeter alternative?+
It depends on the language your team writes. Gatling is the closest move for JVM teams that want code instead of XML test plans. k6 suits JavaScript and TypeScript teams, Locust suits Python teams, and VoltTest suits PHP and Laravel teams. If you rely on JDBC, JMS, LDAP or an air-gapped network, JMeter is still the better fit.
What is the best k6 alternative?+
Artillery is the nearest swap if you want a real Node.js runtime with npm packages or Playwright browser tests. Locust replaces k6 for Python teams, Gatling for JVM teams that want richer reports, and VoltTest for PHP and Laravel teams. JMeter is the alternative when you need protocols k6 does not cover, such as JDBC or JMS.
Which of these load testing tools are open source?+
JMeter (Apache 2.0), Locust (MIT) and k6 (AGPL-3.0) are open source. Gatling Community Edition is Apache 2.0, with gRPC, MQTT and GraphQL under a separate component license. Artillery is MPL 2.0 for most of its code, with its Azure modules under BSL. VoltTest’s PHP SDK and Laravel package are open source; its engine and cloud platform are proprietary.
Which tools support WebSocket or gRPC?+
k6 and Artillery support both. Gatling supports WebSocket under Apache 2.0, and gRPC under its component license, capped in Community Edition. JMeter covers them through plugins, and Locust through a custom Python client. VoltTest supports HTTP/HTTPS only.
Which tools can load test with a real browser?+
k6 has a browser module, and Artillery integrates with Playwright. JMeter (through a WebDriver plugin) and Locust (through the locust-plugins Playwright user) can drive browsers with community add-ons. Gatling and VoltTest generate protocol-level HTTP traffic rather than driving browsers.
Do I need a managed cloud service to load test?+
No. Every tool on this list runs on your own machine. A managed service matters when you need more load than one machine can generate, traffic from several regions, or result history without running servers yourself. For that, k6 has Grafana Cloud k6, Gatling has Gatling Enterprise, JMeter and Locust scripts run on third-party services, Artillery scales out on your own AWS account, and VoltTest has VoltTest Cloud across 24 AWS regions.
Why is VoltTest on this list if VoltTest wrote it?+
Because PHP teams searching for a JMeter or k6 alternative are who we build for. We have tried to be fair to the other five, and the VoltTest section lists the cases where it is the wrong choice: non-PHP teams, WebSocket or gRPC, real-browser tests, and air-gapped environments.

Keep reading

Written by the VoltTest engineering team · Last updated October 2026

Ready to push your limits?

Start with 500 VUs, real cloud infrastructure, and real metrics — no credit card required. Upgrade only when you outgrow it.

Start Free — No Card

Free forever — 500 VUs, 10-minute runs, no credit card