JMeter vs Gatling
JMeter is a pure Java application: you build a test plan in its GUI and run it in GUI or CLI mode across many protocols. Gatling is code-first: simulations are written in Java, Kotlin, Scala, JavaScript or TypeScript on a non-blocking engine. Choose JMeter for protocol breadth and free distributed load; choose Gatling for tests that live in code review.
- JMeter
- The Apache Software Foundation's pure Java load testing application, with a GUI test plan editor, a CLI mode and built-in distributed testing.
- Gatling
- A code-first load testing tool with SDKs for Java, Kotlin, Scala, JavaScript and TypeScript, an open-source engine and a paid Enterprise Edition.
How do JMeter and Gatling compare?
| Dimension | JMeter | Gatling |
|---|---|---|
| How you write a test | JMeterA test plan built in the GUI, saved as JMX XML, run in GUI or CLI mode | GatlingA simulation written in code with a fluent SDK, run from Maven, Gradle, sbt or npm |
| Languages | JMeterNo code for the plan; Groovy, JSR223 or BeanShell for scripted elements | GatlingJava, Kotlin, Scala, JavaScript, TypeScript |
| Architecture | JMeterOne thread per virtual user | GatlingNon-blocking, asynchronous engine designed for many users per node |
| Protocols | JMeterHTTP(S), SOAP and REST, FTP, JDBC, LDAP, JMS, SMTP, POP3, IMAP, TCP, native commands, Java objects | GatlingHTTP, WebSocket, Server-Sent Events, JMS, gRPC and MQTT officially |
| Distributed load | JMeterBuilt in and free: a controller drives remote worker nodes | GatlingCommunity Edition is local only; distributed load generation is an Enterprise Edition feature |
| Reporting | JMeterListeners in the GUI and an HTML dashboard generated from the results file | GatlingA static HTML report per run in Community; live dashboards, history and trends in Enterprise |
| Recording | JMeterBuilt-in test script recorder proxies the browser | GatlingRecorder and HAR file import |
| Version control and review | JMeterJMX files are XML; diffs are noisy and review is hard | GatlingPlain code, readable diffs, ordinary code review |
| Licence and cost | JMeterOpen source, Apache 2.0; no vendor cloud | GatlingOpen source engine, Apache 2.0; Enterprise Edition is paid |
When should you choose JMeter, and when Gatling?
Choose JMeter when
- You need to load a database, message queue, LDAP directory or mail server, not only HTTP.
- You need distributed load across several machines without buying a product.
- The testers on the team prefer building a plan visually to writing code.
- There is an existing library of JMX plans and JMeter expertise to protect.
Choose Gatling when
- The team writes Java, Kotlin, Scala or TypeScript and wants load tests in the same repository and review process.
- You want many virtual users from one machine and the non-blocking engine gives you that.
- The systems under test are HTTP, WebSocket, gRPC or MQTT.
- The organisation is willing to pay Enterprise Edition for dashboards, history and distributed runs.
How does JMeter vs Gatling come up in QA interviews?
Interviewers care less about which tool you used than whether you can design load and read results. Explaining the one-thread-per-user model against a non-blocking engine, and what each means for how many load generators you need, shows you understand the thing under the tool.
- 01Explain the difference between JMeter's threading model and Gatling's engine, and what it means for how much hardware a 10,000-user test needs.
- 02How would you put a JMeter test plan under code review, and what would you do differently with Gatling?
- 03A p95 of two seconds appears under load. How do you decide whether the load generator, the network or the application is the cause?
- 04When would you choose JMeter over Gatling even for an HTTP-only system?
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Common questions about JMeter vs Gatling
Is Gatling better than JMeter?
Gatling is better for teams who want load tests as code and many virtual users per machine. JMeter is better for protocol breadth, visual test building and free distributed load. Both produce reliable results when the load model is right, which is the part most teams get wrong.
Is Gatling free?
The Gatling engine is open source under Apache 2.0 and free for local runs, producing a static HTML report per run. Distributed load generation, live dashboards, run history and team features are in Gatling Enterprise Edition, which is paid.
Can JMeter run distributed tests?
Yes, and without a paid product: JMeter's distributed testing uses a controller that drives remote worker nodes. Setting it up means configuring the JMeter servers and network, which is where most of the effort goes.
Which should I learn for a performance testing role?
JMeter first: it is the tool most performance job descriptions name and its concepts, such as thread groups, samplers, timers and assertions, map to every other tool. Learn Gatling if the roles you want are engineering-led and mention performance tests in code.
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