Open-source alternatives to K6

HttpRunner is a multi-protocol network testing framework designed for automating functional and regression tests of HTTP interfaces. It functions as a multi-protocol network tester supporting HTTP/1.1, HTTP/2, WebSocket, TCP, and RPC to validate diverse communication patterns. The project includes specialized engines for API performance testing, data-driven testing, and a test case generator that converts HAR files, curl commands, and Swagger definitions into executable scripts. The framework is distinguished by its ability to separate test logic from business data via a data-driven execution

Gatling is a load testing framework and traffic generation engine used to measure response times and error rates under heavy load. It functions as an as-code testing library, allowing users to define high-volume traffic simulations and performance tests through programming languages rather than graphical interfaces. The system enables multi-language load simulation and the ability to model concurrent user traffic to identify infrastructure bottlenecks and stability limits. It supports a test-as-code workflow, where version-controlled scripts are integrated into build pipelines as performance

Anteon is a distributed load testing platform and automated performance testing suite designed to simulate high-traffic user scenarios and measure system performance across multiple global locations. It functions as an infrastructure anomaly detector and a service dependency mapper, providing a performance monitoring dashboard to track real-time resource usage across cluster instances. The project distinguishes itself by combining distributed traffic generation with service dependency mapping to identify system bottlenecks through network-level tracing. It incorporates an automated validation

Karate is an end-to-end testing framework and API test automation tool used to validate REST and SOAP APIs, drive browser interactions, and measure system performance. It functions as a unified solution for executing automated tests across both API backends and web frontends. The framework utilizes a custom domain specific language and Gherkin-style feature mapping to define requests and assertions. It includes an API mocking server to simulate backend responses, enabling development and integration testing without live dependencies. The tool covers a broad range of functional testing catego

Autocannon is a Node.js HTTP load tester and benchmarking utility used to measure server throughput and latency. It functions as a high-performance request generator designed for stress testing web servers and APIs to analyze request-per-second capacity. The tool operates as a distributed HTTP load generator capable of aggregating results from multiple machines. It also functions as a HAR file replay tool, allowing users to reproduce specific network traffic patterns by replaying recorded HTTP archive files. The project covers broad capability areas including HTTP traffic simulation through

Flagger is a Kubernetes operator designed to automate the lifecycle of application deployments through progressive delivery. It functions as a controller that monitors custom resource definitions to orchestrate complex release strategies, including canary, blue/green, and A/B testing. By continuously reconciling the desired cluster state with the actual environment, it ensures that deployments adhere to defined specifications while managing the underlying infrastructure required for traffic routing. The project distinguishes itself through a sophisticated metric-driven analysis loop that eval

This project serves as a comprehensive educational repository and technical reference collection, documenting a wide range of software engineering practices and modern development technologies. It provides a structured learning path for developers, curating tutorials and practical examples that cover the full lifecycle of application development, from initial project scaffolding to deployment and maintenance. The repository distinguishes itself by offering deep technical insights into complex architectural patterns, including actor-based concurrency models for managing parallel tasks and cont

This project is a multi-protocol API simulation and mocking system designed to replace external dependencies during development and testing. It provides an API mocking server, a network traffic proxy, and specialized simulators for language model services and identity providers. The system distinguishes itself through deep AI simulation capabilities, including the emulation of language model providers and Model Context Protocol servers using JSON-RPC 2.0. It supports multi-turn conversational logic, state tracking for AI chat APIs, and the visualization of agent execution through call graphs

Locust is a distributed performance testing framework that allows users to define complex system stress scenarios using standard Python code. By modeling concurrent users as classes with weighted tasks and lifecycle hooks, it enables the simulation of realistic user behavior across large-scale environments. The tool functions as a scalable load generator capable of orchestrating traffic across multiple worker nodes to measure system stability and responsiveness under heavy, real-world conditions. The framework is distinguished by its protocol-agnostic architecture, which supports diverse comm

Vegeta is an HTTP load testing tool and library designed to measure the performance and stability of web services. It functions as a command-line utility, a programmable package for integration into other applications, and a distributed load generator capable of splitting request rates across multiple machines. The tool is distinguished by its constant-rate request scheduler, which dispatches requests at a fixed frequency regardless of target response times. It employs lazy target streaming to maintain low memory usage during large tests and uses a binary-encoded storage format to minimize di

This project is a performance benchmarking framework and network protocol stress tester designed to evaluate system stability under high-concurrency conditions. It functions as a command-line utility that simulates massive volumes of simultaneous requests to identify infrastructure bottlenecks and verify service reliability. The tool distinguishes itself through its protocol-agnostic orchestration, which allows for load testing across diverse standards including HTTP, WebSocket, gRPC, and Radius. It supports complex request configurations, enabling users to inject custom headers, binary data,

dperf is a high-performance network testing tool that generates massive multi-protocol traffic for benchmarking network devices and servers. It uses DPDK to bypass the kernel network stack, enabling line-rate packet generation and capture with zero-copy processing, and implements a full TCP/IP stack in user space to achieve millions of connections per second from a single server. The tool is designed for stress-testing Layer 4 load balancers and gateways, capable of simulating billions of concurrent TCP or UDP sessions and generating tens of millions of new connections per second. It supports

httpstat is a network latency diagnostic tool and HTTP request performance analyzer. It measures and visualizes the timings of DNS lookups, TCP connections, and TLS handshakes to identify specific network bottlenecks. The project functions as a JSON HTTP metrics exporter and a service level objective validation tool. It compares captured network request timings against predefined performance thresholds to detect violations and can export structured timing and response data in JSON or JSONL formats. The tool provides capabilities for automated API diagnostics and network latency troubleshooti

This project is a command-line HTTP load testing tool designed to measure the throughput and latency of web servers under high-concurrency conditions. It functions as a multi-threaded benchmarking engine that simulates thousands of simultaneous connections to evaluate server performance, identify bottlenecks, and determine capacity limits. The tool distinguishes itself through a shared-nothing thread architecture that isolates state within individual threads to eliminate lock contention during high-frequency request generation. It utilizes a non-blocking event loop and low-latency socket poll

This project is a command-line utility designed for HTTP load testing and network stress testing. It functions as a benchmarking tool that generates high volumes of concurrent traffic to evaluate the performance, reliability, and throughput capacity of web applications and APIs under sustained load. The tool allows for precise control over traffic generation by enabling users to configure request parameters, including custom headers, authentication credentials, and specific HTTP methods. It manages load through a worker-pool system that regulates request frequency, allowing for both time-boun

Tape is a JavaScript testing framework and assertion library that serves as a test runner for Node.js and browser environments. It implements the Test Anything Protocol to provide a standardized, machine-readable format for test results. The project functions as a cross-environment test harness, allowing the same test suites to be executed across both server-side and client-side environments while maintaining a consistent output protocol. Its capabilities include validating value equality and truthiness, verifying exception handling, and coordinating asynchronous workflows. The framework als

Hey is a command-line utility designed for HTTP load testing and API performance benchmarking. It functions as a concurrent request generator that simulates high volumes of traffic against target endpoints to evaluate service responsiveness, throughput, and stability under load. The tool distinguishes itself by integrating specialized modules for cryptographic request signing and internal service authorization. It supports the generation of digital signatures for decentralized social protocols and validates backend requests using shared secret tokens, allowing for secure interaction with prot

Goja is a JavaScript engine and ECMAScript compliant interpreter implemented entirely in Go. It serves as an embedded scripting engine that allows Go applications to execute JavaScript code and integrate a programmable scripting layer without relying on Cgo or external native dependencies. The project functions as a bridge between Go and JavaScript, enabling bidirectional data exchange and function invocation. It allows Go hosts to expose native structs, slices, and maps as JavaScript objects and arrays, while providing mechanisms to export script values and functions back into native Go type

Implementation of a bulletproof node.js API 🛡️

Siege is an HTTP benchmarking utility and load testing tool used to analyze transaction rates and response times. It functions as a stress testing tool that pushes web servers to their limits to determine maximum sustainable load and failure points, while also serving as a performance analyzer for encrypted HTTPS connections. The tool distinguishes itself by simulating human browsing behavior through the use of random delays between requests and local management of cookies and authentication headers. This allows for more realistic user simulation and the assessment of server stability under c

tcpcopy is a network traffic replication tool and mirroring system designed to capture live TCP streams and replay packet captures for performance and stress testing. It functions as a low-level packet capturer that filters data at the link layer to minimize loss while duplicating real-world traffic from production servers to test environments. The tool distinguishes itself through TCP state machine simulation, which tracks sequence numbers and flags to modify packet headers and forge source identities. This allows the system to deceive target servers into accepting mirrored connections and s

Gor is a set of specialized utilities for recording, replaying, and shadowing network traffic to validate system behavior under real-world conditions. It functions as an HTTP traffic recording tool, a network traffic capture engine, and a system for duplicating live production traffic. The project provides capabilities for recording real-time HTTP network traffic and storing it for later playback or analysis. It can duplicate live production network traffic and redirect it to a staging environment in real time, or replay recorded network requests against a target environment to validate syste

QUnit is a JavaScript unit testing framework designed to verify code behavior using assertions and lifecycle hooks across browsers and server runtimes. It functions as a browser-based test runner with an HTML interface for reporting results, an asynchronous test orchestrator for coordinating callbacks, and a utility for isolating and verifying document object model changes. The framework distinguishes itself through specialized DOM testing capabilities, allowing for the isolation and resetting of the document object model between tests to ensure atomicity. It also features a system for detect

FrankenPHP is a Go-based PHP runtime and application server that integrates a web server and PHP interpreter to host applications without requiring a separate process manager. It functions as a worker mode server that keeps applications in memory across requests to eliminate bootstrap overhead and a static binary bundler that packages applications and the server into a single self-contained executable. The project distinguishes itself by allowing the embedding of a PHP runtime directly into Go programs and enabling the development of PHP extensions using the Go language. It also includes a bu

This project provides infrastructure for simulating, benchmarking, and implementing high-volume concurrent network connections to test server scalability. It includes a high-concurrency WebSocket server and a corresponding load tester designed to verify the capacity of servers to handle millions of simultaneous connections. The system utilizes a containerized connection simulator to mimic massive traffic volumes across multiple isolated environments. This allows for the deployment of scaled client instances to perform WebSocket load simulations and stability verification. The implementation

Jasmine is a JavaScript testing framework and test runner designed for behavior-driven development. It provides a comprehensive toolset for writing and executing descriptive test suites that verify code behavior in both web browsers and Node.js environments. The framework is distinguished by its integrated mocking library, which allows for dependency isolation through spies and stubs, as well as the ability to simulate time and timing functions to test asynchronous logic synchronously. It also includes a mechanism to enforce test uniqueness, preventing duplicate names for tests and suites. I

Rest-assured is a Java-based REST API testing framework and HTTP client library designed for automating web service tests. It provides a fluent domain-specific language and assertion library to send HTTP requests and validate response metadata, including status codes, headers, cookies, and bodies. The framework is distinguished by a method-chaining DSL that creates readable specifications for API interactions. It features a filter-based request interception pipeline, object-mapping serialization for converting Java objects to JSON or XML, and a path-based parsing system to isolate specific fi