Network condition simulator for system-wide and per-application testing
Experience intentional network degradation across the system or for a single process: latency, packet loss, bandwidth caps and scripted connection changes. Bean Network Tester, from DonislawDev, is an open-source Windows utility aimed at developers and QA engineers. It pairs a GUI and CLI with replayable stochastic patterns and pre-made profiles so teams can reproduce flaky-network bugs, validate error handling, and integrate tests into automated workflows.
It injects realistic faults into live traffic without changing application code
Bean Network Tester intercepts packets using the included WinDivert driver and modifies traffic at the kernel level, so you don't alter proxies or app configuration. Capabilities include fixed or random latency and jitter, packet loss/corruption/duplication, bandwidth throttling, and active connection tearing such as TCP resets and flapping. Targeting works by process name, PID, IP, port, or address family, which lets you affect only the application under test.
It supports reproducible, private testing workflows suitable for automation
The tool offers a seed system that replays the same random loss and jitter patterns for consistent bug reports, and a Scenario System for scripted sequences of network changes. In addition, it provides both a graphical interface with live charts and a CLI with machine-readable output, which makes integration into CI/CD pipelines possible. The app collects no telemetry and operates offline, preserving test privacy.
It operates at kernel level and requires elevated rights, so plan deployment carefully
Because the tool uses a kernel interception driver, the application must run with Administrator privileges on Windows. The live monitoring includes charts, counters, and a searchable connections table to observe impact in real time, but the kernel-level approach means IT policies or restricted desktops may block installation. Developers, QA, game studios, and network admins gain control, provided they can install the driver and run elevated processes.
A practical pick for technical teams, with a single operational caveat
Bean Network Tester suits development and QA teams that need repeatable, private network experiments during the build and test cycle. The main operational trade-off is the requirement for Administrator access to install and run the kernel-level interception driver, which raises deployment friction on tightly managed machines. For labs and developer workstations the tool offers a focused way to validate network resilience.
