Artillery

Artillery is a modern, open-source load testing and functional testing toolkit for HTTP, WebSocket, Socket.IO, and gRPC protocols, written in Node.js. Created by Hassy Veldstra, Artillery enables engineering teams to test the performance and reliability of their APIs and services under realistic load conditions without writing complex test scripts. Test scenarios are defined in YAML or JSON, describing virtual user (VU) behavior through step sequences, request payloads, think time between requests, and conditional logic. Features include: phased load profiles (ramp-up, steady state, ramp-down with configurable arrival rates from 1 to 100,000+ virtual users per second), HTTP/1.1 and HTTP/2 protocol support, WebSocket and Socket.IO testing for real-time applications, gRPC unary and streaming testing, request capture and correlation (extracting values from responses using JSONPath, regex, or XPath for use in subsequent requests), payload fuzzing from CSV data files for parameterized testing, custom plugin system (metrics plugins for Datadog, Prometheus, InfluxDB, custom engine plugins in JavaScript), think time and loop control, assertions and checks for functional validation, TLS certificate and client auth support, proxy support, and CSV/HTML/JSON test report generation. Artillery Cloud provides managed load generation from multiple geographic regions. As of 2026, version 2.x has over 8,400 stars.