Open-source alternatives to Tcpcopy

GoReplay is a network traffic recording and replay tool used to capture live HTTP and binary protocol requests. It functions as a traffic shadowing proxy that duplicates incoming network requests to test environments and a utility for recording traffic to local or cloud storage for later analysis and playback. The system is capable of processing non-textual data formats, such as Thrift and Protocol Buffers, allowing for the capture and replay of specialized application-to-application communication. The tool supports live traffic capture and asynchronous duplication to validate infrastructure

Zapret is a deep packet inspection bypass tool and packet manipulation framework designed to circumvent network censorship. It operates as a transparent network proxy and TCP traffic obfuscator that modifies packets to deceive network inspection systems. The project distinguishes itself through advanced desynchronization strategies, including the modification of TLS client hello handshakes and the use of fake packet injection. It utilizes a combination of TCP stream segmentation, sequence overlapping, and TTL adjustment to hide prohibited requests from firewalls while ensuring the destination

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

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

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

k6 is a developer-centric load testing suite and command-line load generator designed for network performance validation. It functions as a JavaScript load testing tool that utilizes a Go-based runtime engine to simulate concurrent user traffic and validate API responses across HTTP, gRPC, and WebSockets. The project distinguishes itself by using code rather than a graphical interface to define workload scenarios and performance thresholds. It features a pluggable protocol architecture and an extension ecosystem that allows for the addition of custom protocols and specialized testing capabili

Impacket is a Python network protocol library and low-level implementation foundation. It provides a collection of classes for implementing and manipulating network protocols such as SMB, TCP, and UDP. The project serves as a network authentication framework for verifying user identities using passwords, hashes, and security tickets. It also functions as a network packet manipulation toolkit and security research tool for analyzing protocol behaviors and identifying vulnerabilities. The library covers the creation, parsing, and modification of raw network data to analyze communication stacks

GreenTunnel is a network utility designed to circumvent deep packet inspection and bypass internet censorship. It functions as a tool that modifies outgoing network packets and encrypts DNS lookups to prevent internet service providers and network filtering systems from detecting and blocking specific web destinations. The project implements an HTTP fragmentation proxy and an HTTPS handshake fragmenter. These components split request headers and TLS handshake records across multiple segments to conceal hostnames and destination server names from inspection systems. The software also includes

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

udp2raw is a network tunneling tool designed to bypass firewalls and obfuscate UDP traffic. It wraps UDP packets in alternative headers and utilizes raw socket networking to move data through networks that otherwise block or throttle UDP traffic. The project distinguishes itself by simulating TCP connections, mimicking the three-way handshake and sequence numbering to trick firewalls into treating UDP streams as TCP traffic. It further stabilizes these connections through heartbeat-driven port rotation, which automatically switches ports to recover sessions after detected failures. The tool

Clumsy is a Windows network fault injection tool that intercepts system-wide network traffic at the kernel level using the WinDivert driver, without requiring proxy configuration or application code changes. It captures and manipulates packets for all running applications, including localhost connections, enabling controlled testing of application behavior under degraded network conditions. The tool provides comprehensive network impairment capabilities including latency simulation, bandwidth throttling, packet loss, corruption, duplication, and reordering. Users can apply these impairments s

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,

Bettercap is an extensible framework for network security testing that provides a unified interface for performing man-in-the-middle attacks, network reconnaissance, and traffic manipulation across WiFi, Bluetooth, and wired networks. It operates through a modular attack module system that loads and executes interchangeable offensive or diagnostic modules, supported by event-driven session management and multi-protocol network spoofing capabilities. The framework distinguishes itself by covering a broad range of network domains, including Bluetooth Low Energy scanning and enumeration, CAN-Bus

Mitmproxy is an interactive, programmable network proxy engine designed for traffic analysis and protocol manipulation. It functions as a gateway that intercepts, inspects, and modifies network traffic in real-time, supporting HTTP, HTTPS, WebSocket, DNS, and generic TCP or UDP streams. By acting as a trusted certificate authority, the proxy can dynamically generate and sign certificates to decrypt and analyze secure TLS-encrypted connections. The project distinguishes itself through a highly extensible, event-driven architecture that allows users to automate traffic transformation using cust

Ethical-Hacking-Labs is a comprehensive cybersecurity training curriculum and lab suite designed for learning penetration testing, network analysis, and offensive security techniques. It provides a structured environment for practicing the full attack lifecycle, from initial reconnaissance and scanning to exploitation and post-compromise analysis. The project provides instructional materials and guided exercises that cover specific technical domains, including open source intelligence research and network security courseware. It includes a practical workbook for identifying system vulnerabili

Reqable is a cross-platform network debugging tool that functions as an HTTP/HTTPS debugging proxy, a REST API client, and a traffic replay tool. It captures, inspects, and modifies live traffic using a local MITM proxy engine, supports VPN tunnel capture for mobile devices, and provides a Python scripting sandbox for custom traffic processing. The application is available on Windows, macOS, Linux, iOS, and Android. The tool distinguishes itself by combining traffic interception with breakpoint-based request modification, allowing users to pause live HTTP traffic for manual inspection and alt

moco is a multi-protocol mock server and programmable API stub used to simulate HTTP, REST, WebSocket, and Server-Sent Events endpoints. It enables the creation of fake backend services to facilitate development and integration testing without requiring a live server. The project distinguishes itself through its ability to act as a network traffic replay tool, capturing real request-response pairs via a proxy and playing them back locally. It also supports bidirectional communication simulations, including WebSocket server simulation and SSE stream simulation with configurable delivery delays

mcp-use is a development framework designed for building, deploying, and managing servers, clients, and autonomous agents using the Model Context Protocol. It provides a comprehensive toolkit for creating servers that expose custom tools, data resources, and prompts to compatible AI agents. The project distinguishes itself by offering a complete lifecycle for protocol-based applications, including a dedicated hosting platform for production servers and a compliance validator to ensure servers meet marketplace publishing requirements. It also features an observability suite for tracing protoco

Open vSwitch is a software-defined network switch and high-performance data plane engine. It functions as a virtual layer 2 switch and network orchestrator, implementing the OpenFlow protocol to decouple the control plane from the data plane for programmable network forwarding. The project distinguishes itself through a userspace-kernel datapath split and the use of poll-mode drivers for kernel-bypass acceleration. It provides a network tunneling gateway to extend virtual networks across physical hosts and utilizes a transactional, schema-based configuration database with state replication fo

ExHyperV is a suite of administrative tools designed for managing advanced Hyper-V configurations, specifically focusing on GPU partitioning, device passthrough, and virtual network switches. It provides a graphical interface to configure virtual machine resources and optimize hypervisor settings. The project is distinguished by its ability to share physical graphics card resources across multiple virtual machines using paravirtualization and partitioning. It also provides specialized utilities for assigning PCIe devices and USB peripherals directly to guest machines for exclusive access. Th

sshuttle is an SSH tunneling proxy and user-space network router that forwards local network traffic to a remote network via an encrypted SSH connection. It serves as an alternative to traditional VPN installations for routing traffic and accessing private remote resources. The project functions by redirecting network traffic through an SSH tunnel without requiring administrative privileges on the remote server. It utilizes a user-space TCP/IP stack to process packets, allowing it to operate without kernel-level administrative access. Its capabilities cover remote network access, secure remo

Strix is an automated security research and vulnerability scanning platform that leverages language models to orchestrate complex security analysis tasks. It functions as a comprehensive framework for penetration testing and continuous security integration, allowing users to embed automated vulnerability research directly into development pipelines or execute it within isolated, containerized environments. The platform distinguishes itself through a multi-agent orchestration engine that coordinates specialized autonomous agents to perform parallel security assessments. By integrating LLM-agno

Playwright for Python is a browser automation framework designed for end-to-end testing, web scraping, and user interaction simulation. It functions as a headless browser controller that enables programmatic navigation, data extraction, and the execution of complex workflows across multiple rendering engines. The framework distinguishes itself through an actionability-aware interaction engine that automatically verifies element readiness before performing actions, significantly reducing test flakiness. It utilizes isolated browser contexts to maintain separate storage and cookies for parallel

This project is a comprehensive software observability suite and application performance monitoring platform designed to track runtime errors, performance bottlenecks, and system health. It functions as a centralized diagnostic service that aggregates and categorizes exceptions, providing the infrastructure necessary to visualize complex execution paths across distributed systems and microservices. The platform distinguishes itself through a high-throughput distributed event ingestion pipeline and a columnar storage analytics engine that enables rapid aggregation of large-scale performance me

A wrapper around Artillery to run performance tests on Nostr Relays