locust
Developer-friendly load testing framework
Decision gist · record as of 2026-08-14
Yes. Locust is actively maintained, has no known vulnerabilities, installs with low friction, and is well-suited for teams that prefer writing tests in Python over GUI-based tools. The permissive MIT license removes legal friction. Install it if you need load testing with code-based test definition, distributed scaling, and real-time monitoring—especially for HTTP services or when you want to avoid proprietary testing platforms.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Requires Python 3.11 or later.
- Low install friction with a pure-Python wheel distribution.
- Actively maintained with a recent release (13 days ago) and strong community engagement (28071 GitHub stars).
License · maintenance · safety
MIT (permissive) — MIT license is permissive, allowing commercial and private use with minimal restrictions—you may use, modify, and distribute Locust freely as long as you include the license notice.
last release 2026-08-01 (13 days) · last repo commit 2026-08-10 · 28,071 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 14,055,255 downloads/mo, #1,250 on PyPI
Alternatives
Verify before relying
pip install locust
from locust import HttpUser, task, between
class TestUser(HttpUser):
wait_time = between(1, 2)
@task
def test_endpoint(self):
self.client.get("/api/endpoint")- Whether gevent-based concurrency model meets specific throughput or latency requirements for your workload.
- Performance characteristics when scaling to hundreds of thousands of users.
- Compatibility with custom protocol clients beyond HTTP.
What it is and what it does
Locust is a developer-friendly load testing framework that lets you write performance tests in regular Python code rather than XML or domain-specific languages. Tests define user behavior using Python classes and decorators, with each simulated user running in its own lightweight greenlet (via gevent), enabling natural blocking-style code. The framework supports distributed testing across multiple machines to simulate concurrent users, and provides both a web-based UI for real-time monitoring and command-line execution for CI/CD integration.
You write test scenarios as Python code, import libraries freely, and leverage Locust's pluggable architecture to extend or adapt behavior. The framework can test HTTP services by default and is extensible to other protocols. Results—throughput, response times, errors—are viewable in real time and exportable for analysis. Its small, intentionally minimal codebase makes it easy to customize for specific use cases without being locked into a GUI or predefined patterns.
Use it for
- Simulate concurrent HTTP traffic to measure web service response times and throughput under load before production deployment.
- Run distributed load tests across multiple machines to stress-test APIs with concurrent users.
- Automate performance regression testing in CI/CD pipelines by running headless Locust tests and exporting results.
- Test non-HTTP protocols or custom systems by writing a client in Python and plugging it into Locust's user model.
- Monitor real-time test progress via the web UI and adjust load parameters mid-test without stopping the scenario.
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes.
Locust is actively maintained, has no known vulnerabilities, installs with low friction, and is well-suited for teams that prefer writing tests in Python over GUI-based tools. The permissive MIT license removes legal friction. Install it if you need load testing with code-based test definition, distributed scaling, and real-time monitoring—especially for HTTP services or when you want to avoid proprietary testing platforms.
Install
locust on PyPI
Before you install
Low install friction with a pure-Python wheel distribution. Actively maintained with a recent release (13 days ago) and strong community engagement (28071 GitHub stars). Supports current Python versions (3.11–3.15).
Requires Python 3.11 or later.
License in practice
MIT license is permissive, allowing commercial and private use with minimal restrictions—you may use, modify, and distribute Locust freely as long as you include the license notice.
Quickstart
pip install locust
from locust import HttpUser, task, between
class TestUser(HttpUser):
wait_time = between(1, 2)
@task
def test_endpoint(self):
self.client.get("/api/endpoint")Verify before relying
- Whether gevent-based concurrency model meets specific throughput or latency requirements for your workload.
- Performance characteristics when scaling to hundreds of thousands of users.
- Compatibility with custom protocol clients beyond HTTP.
Package facts
| License | MIT permissive |
| Python support | Supports the current Python release >=3.11 |
| Install friction | Low. Pure-Python wheel |
| Runtime dependencies | 16 packagesconfigargparseflask-corsflask-loginflaskgeventgeventhttpclientmsgpackpsutilpytestpython-engineiopython-socketiopywin32pyzmqrequeststyping-extensionswerkzeug |
| Maintenance | Actively maintained 13 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 14,055,255 / month, #1,250 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Development Status :: 5 - Production/StableIntended Audience :: DevelopersIntended Audience :: System AdministratorsLicense :: OSI Approved :: MIT LicenseOperating System :: OS IndependentProgramming Language :: PythonProgramming Language :: Python :: 3Programming Language :: Python :: 3.11Programming Language :: Python :: 3.12Programming Language :: Python :: 3.13Programming Language :: Python :: 3.14Programming Language :: Python :: 3.15Topic :: Software Development :: TestingTopic :: Software Development :: Testing :: Traffic GenerationTopic :: System :: Distributed Computing |
Evidence: locust-2.46.3-py3-none-any.whl
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