HTTP/2 & HttpClient 5
One modern HTTP stack with first-class HTTP/2, protocol negotiation, NTLM that works, and Brotli/Zstandard decoding.
BreakTest
The JMeter workflow you already know, with the engine and editor it should have had: HTTP/2 on a modern client, Java 21, 50–80% less memory, real undo/redo, and a results tree that shows what you're actually debugging. AI Repair ships in the free tool, so Claude Code or Codex can fix your plans right on your machine.
Forked from JMeter 5.6.3. Your JMX files and most plugins keep working.
Forked from JMeter 5.6.3
Java 21+
JMX compatible
HTTP/2 first
AI Repair included free
What you get
The daily-use improvements
The familiar test-plan model, minus the parts that made it a chore.
Half the memory
Lazy decompression, response retention modes, and per-thread buffer reuse help big tests fit on smaller machines.
AI Repair & auto-scripting
A built-in MCP server lets Claude Code or Codex inspect, repair, validate, and rerun your plans, either as a full pass or from targeted instructions.
Open and closed workload models
One Thread Group covers classic ramp-and-hold phases and open-model arrivals per second, with a schedule preview graph.
Parallel & Fork controllers
Browser-like concurrent requests and independent work branches without thread-group workarounds.
Pause and resume
Pause a running test from the GUI or the command port, see what's happening, and resume without restarting a long run.
A results tree for debugging
Endpoint, HTTP/TLS metadata, cookies, variables, binary/text detection, and jump-to-source from any sample.
Real undo and redo
Semantic history for add, delete, move, update, and search-replace. Restructure a 2,000-element plan without holding your breath.
Modern light & dark themes
FlatLaf-based styling and compact layouts, plus background loading so large plans open fast.
Correlation that fails loudly
All extractor types can fail the sampler when nothing matches, so you find broken correlation at the source instead of downstream.
Better test data handling
Random CSV record order, a preview of the first variable assignments, and clean per-iteration variables.
Missing plugins don't block you
Plans with unavailable plugin elements open with disabled placeholders, so you can inspect and migrate instead of being locked out.
See it work
Debugging that answers questions.
When a script misbehaves, the answer is in the details. The results tree puts them in one place instead of spreading them over logs.
- Failed extractors fail the sampler on the spot
- Endpoint, TLS, timing, cookies, and variables per sample
- Recorded vs. replayed diffs for scripts imported from HAR
- Jump straight from a sample to the test element that produced it
- Timeouts reported as one readable line, not a stack trace
- Validation runs skip pacing sleeps, so checks take seconds
Compatibility
Familiar, but not frozen.
What keeps working
- Existing JMeter JMX files, for common test plans.
- Most plugins, with HttpClient 4 jars retained for compatibility.
- Legacy saved values are mapped where practical.
- A
BreakTest JMXvariant adds metadata for features JMeter doesn't have (HAR diffs, AI context).
What we deliberately dropped
- BeanShell, BSF/JEXL2, Rhino JS, LogKit, and the legacy HTTP implementations.
- RMI Remote Server, because distributed runs belong in Enterprise.
- Plugins hooking those removed internals will need migration.
- The trade is explicit: a better tool over preserving every edge case forever.
Free, just like JMeter.
BreakTest's full GUI, runtime, and AI Repair are free to use. When you're ready to run at scale, BreakTest Enterprise also offers a free, renewable on-premises license for up to 250 virtual users, with unlimited tests and test hours.