Locust

Active

Country: Sweden (SE)
Founded: 2011
Developer: Locust community (open source project)
Pricing: Free (open-source)
Open source: Yes
Platforms: Linux, macOS, Windows

Indexes

API Testing

Overview

Locust is an open source load testing tool for HTTP and other protocols that allows users to define test behaviors in regular Python code rather than UIs or domain-specific languages.¹³⁴ It supports running tests via command line or a web-based UI, with real-time monitoring of throughput, response times, and errors, and export options for analysis.³⁴ Designed for developers, it enables scalable, scriptable performance testing.²³

Key Features

Python-based test definition - User behaviors are scripted in plain Python code for flexibility and extensibility.
Web-based UI - Provides a browser interface to configure and monitor tests with number of users, spawn rate, and host settings.
Real-time metrics - Displays throughput, response times, and errors during test execution.
Command-line execution - Supports running tests directly from the terminal without the web UI.
Distributed testing - Scales tests across multiple machines for high load simulation.
Export capabilities - Exports test results for later analysis.
HTTP and other protocols - Tests web services and additional protocols beyond HTTP.

Pricing

Plan	Price	Includes
Community	Free	Full open source features via self-hosting.

Platforms & Requirements

Locust runs on any platform supporting Python 3.8+, including Linux, macOS, and Windows.³ It requires a Python environment and can be installed via pip; no specific hardware minimums beyond standard Python requirements. Limitations are tied to Python compatibility rather than platform-specific issues.

Integrations & Ecosystem

Python libraries for HTTP clients (e.g., requests)
Command-line tools
Web UI for configuration
CSV/JSON export for results
Gevent for asynchronous execution
Distributed mode via master-worker setup

Alternatives

App	Difference
JMeter	GUI-based with domain-specific language; less developer-friendly for Python users.
Gatling	Uses Scala DSL; compiled for performance but not Python-native.
k6	Scripted in JavaScript; focuses on cloud-native and CI/CD integration.
Artillery	Node.js-based YAML/JS scripting; simpler for non-Python developers.

Reputation

Locust is praised for its developer-friendly Python scripting, making it accessible for coders to create flexible load tests without restrictive UIs.¹²³ Users appreciate real-time web monitoring and scalability for distributed testing.⁴ Some note a learning curve for Python novices and that Locust Cloud service has shut down, shifting reliance to self-hosted open source use.⁵

Sources (5)