Best Free and Open Source Software, and many more

posted by Rianne Schestowitz on Sep 09, 2026

• Best Free and Open Source Alternatives to Google reCAPTCHA

  Google reCAPTCHA is a CAPTCHA and bot-detection service designed to protect websites and applications from spam, automated abuse and fraudulent activity. It uses risk analysis to distinguish legitimate visitors from automated traffic, with implementations ranging from checkbox and visual challenges to score-based verification that can operate without asking the visitor to solve a puzzle.

  reCAPTCHA is proprietary software. We recommend the best free and open source alternatives.

• 5 Best Free and Open Source Earth Observation and Ocean Science Tools

  There is plenty here for oceanographers, Earth scientists, remote-sensing specialists, environmental researchers and geospatial analysts. The software also has practical uses far beyond the laboratory, including monitoring coastlines, studying marine pollution, tracking environmental change, supporting fisheries research and helping us understand the forces shaping our oceans and atmosphere.

  Some of the tools are geared towards interactive exploration and visualisation. Others are built for heavyweight processing, automated workflows and large datasets. Together they offer an impressive open source toolbox for examining our planet from high above the clouds to deep beneath the waves.

  Here’s our verdict captured in a legendary LinuxLinks-style ratings chart. Only free and open source software is eligible for inclusion here.

• WHAD Client - Wireless Protocol Exploration Framework

  WHAD Client is a Linux command-line framework for exploring wireless protocols through hardware that implements the Wireless Hacking Devices protocol. It combines a Python development library with focused utilities for capture, analysis, replay and controlled traffic generation. Interactive shells are also available for several protocol-specific activities and supported devices.

  This is free and open source software.

• detect-secrets - detect and prevent secrets in source code

  detect-secrets is a command-line toolkit for finding credentials in source code and preventing new secrets from entering a repository.

  Its central concept is the baseline: a snapshot of known findings that lets a team acknowledge existing technical debt while still blocking newly introduced secrets. This approach is particularly useful for large codebases where removing every historical credential immediately may be unrealistic. The project separates scanning, commit-time enforcement and human review into distinct workflows, so teams can tune detection without treating every potential match as a confirmed leak.

  This is free and open source software.

• XicTools - electronic design and circuit simulation suite

  XicTools is a collection of electronic design automation software centred on Xic and WRspice. Xic is a graphical editor for integrated circuit layouts and schematics, while WRspice is a SPICE-derived circuit simulator.

  The suite has a long development history and includes tools for circuit simulation, physical layout, device extraction, routing, Verilog simulation, and related electronic design tasks. Xic and WRspice were originally commercial applications before being released as open source.

  This is free and open source software.

• Fluxion - Wireless Security Auditing Tool

  Fluxion is a terminal-based TUI and command-line framework for authorised wireless security assessments.

  It helps testers evaluate whether users and wireless deployments are susceptible to rogue access-point and captive-portal attacks. The software is designed for controlled laboratory environments and networks where the operator has explicit permission to conduct security testing.

  This is free and open source software.

• Gitleaks - detect secrets in Git repositories and files

  It is designed for both local developer use and automated security workflows, with a configurable detection engine rather than a hard-wired set of checks. Gitleaks can inspect a working tree as well as Git history, making it useful both for preventing new leaks and for examining repositories that may already contain sensitive material. Upstream describes the project as feature complete, with future work focused on security fixes rather than new functionality.

  This is free and open source software.

• hympd - simple responsive web interface for MPD

  hympd is a web-based interface for Music Player Daemon (MPD). It provides a clean way to control an MPD server from a desktop or mobile browser without installing a dedicated client.

  The interface is deliberately minimal and responsive, with layouts suitable for both large and small screens. It connects to an MPD instance and exposes the everyday controls needed to browse a music collection, manage playback and work with the current queue. The application is supplied as a self-contained statically linked executable which embeds its CSS, JavaScript, icons and other web resources, avoiding runtime dependencies.

  This is free and open source software.

• tenki - terminal clock with animated weather effects

  tenki is a terminal clock that combines a large digital time display with animated weather-style effects. Its name is the Japanese word for weather. The program is built with Ratatui and offers a visually distinctive alternative to a conventional terminal clock.

  The clock can be paired with rain, snow, or meteor animations, or the effect can be disabled entirely. Behaviour is controlled from command-line options, including animation intensity, wind direction, frame rate, tick rate, colour, and display behaviour.

  This is free and open source software.

• Termitype - feature-rich terminal typing test

  Termitype is a terminal user interface (TUI) typing test designed for practising and measuring typing speed without leaving the terminal.

  Inspired by Monkeytype, it combines a keyboard-driven interface with extensive configuration and several ways to customise both the typing test and its presentation.

  Tests can be configured by duration or word count, with options to introduce punctuation, numbers, symbols, and alternative language dictionaries. Most settings can be changed interactively from Termitype’s built-in menu as well as from command-line options.

  This is free and open source software.

• QucsatorRF - RF and microwave circuit simulator

  QucsatorRF is a command-line circuit simulation engine designed particularly for radio-frequency and microwave circuits. It serves as a specialised simulation backend for Qucs-S, which provides a graphical interface for schematic capture, simulation control, and visualisation.

  The simulator accepts a network list as input and generates results using the Qucs XML dataset format. While general-purpose circuit simulation is possible, its main strength is RF and microwave modelling, complementing SPICE-compatible engines such as Ngspice used by Qucs-S.

  This is free and open source software.

• MERK - cross-platform graphical IRC client

  MERK is a cross-platform graphical Internet Relay Chat (IRC) client built around a multiple-document interface. Each server, channel, and private conversation can have its own subwindow, offering an interface reminiscent of classic IRC clients such as mIRC. It combines an approachable graphical interface with extensive configuration, scripting, and plugin facilities.

  This is free and open source software.