Best Free and Open Source Software

posted by Rianne Schestowitz on Sep 13, 2026

• Best Free and Open Source Alternatives to Google Cloud Run

  Google Cloud Run is a managed application platform designed to run containerised applications without requiring users to manage the underlying infrastructure. It automatically handles tasks such as scaling, networking and deployment, and can scale workloads down to zero when they are not being used.

  Cloud Run supports web services, APIs, background processing and other workloads packaged as containers. Developers can concentrate on their application while Google manages the servers and much of the operational complexity.

  Google Cloud Run is proprietary software. We recommend the best free and open source alternatives.

• 5 Best Free and Open Source Linux Honeypot Tools

  These tools are useful for system administrators, network defenders, security researchers, incident response teams, and anyone interested in understanding how attackers probe and abuse internet-facing services. They can complement firewalls, intrusion detection systems, and log monitoring by providing a controlled environment in which suspicious behaviour is easier to isolate and study.

  The software featured here covers several different approaches. Some applications emulate multiple network protocols and services, making them suitable for broad monitoring across an infrastructure. Others focus on capturing malware and exploit attempts, recording usernames and passwords submitted by attackers, detecting abuse of SIP and VoIP services, or monitoring hostile activity directed at web applications.

  All of the programs selected are free and open source, allowing administrators to inspect the code, adapt deployments to their own environments, and integrate captured data with wider security monitoring workflows.

  Here’s our verdict captured in a legendary LinuxLinks-style ratings chart.

• Best Free and Open Source CAPTCHA Tools

  The software featured here takes a different approach. It focuses on privacy and generally avoids intrusive puzzles or behavioural profiling. Proof-of-work techniques can instead ask the visitor’s browser to perform a small computational task which the server verifies before accepting the request.

  These tools are useful for developers, website administrators and self-hosters who want effective bot protection without handing visitor data to external services. They range from lightweight components that are easy to add to a website to more configurable self-hosted systems.

  Here’s our verdict captured in a legendary LinuxLinks-style ratings chart. Only free and open source tools are eligible here.

• Gojekyll – Jekyll-compatible static site generator

  Gojekyll is a static site generator written in Go that implements a substantial portion of Jekyll’s behaviour and project conventions.

  Its purpose is to let existing Jekyll-style websites benefit from a compiled Go implementation while retaining familiar concepts such as front matter, Liquid templates, layouts, includes, collections and data files. Compatibility is intentionally substantial rather than complete, so projects relying heavily on arbitrary Ruby plugins may require adjustments.

  Gojekyll supplies both build and development-server workflows and is particularly useful for repeatedly rebuilding sites while content or templates are being edited.

  This is free and open source software.

• paq - fast BLAKE3 file and directory hashing

  Directories are processed recursively through a parallel pipeline. paq hashes discovered content, sorts the resulting hashes to keep output deterministic, and then hashes that ordered set to produce the final value. The tool deliberately concentrates on content rather than filesystem metadata, so ownership, permissions, timestamps, ACLs, extended attributes, and hard-link information do not contribute to the resulting hash. Symbolic links are handled by hashing their target paths rather than following and hashing the target contents.

  paq can be used as a standalone executable or as a Rust crate. The command-line tool writes its result to a .paq file as valid JSON, while the crate exposes hashing functionality for Rust applications. Hidden files and directories can optionally be ignored.

  This is free and open source software.

• rofimoji – emoji and Unicode character picker

  rofimoji is a searchable character picker that works with rofi and a range of similar menu programs.

  It is aimed primarily at emojis and Unicode characters, but its bundled collections also cover CJK characters, Font Awesome, Nerd Fonts, Gitmoji, kaomoji and HTML named character references. The program can type a selected character into the active application, copy it to the clipboard, print it to standard output or expose its Unicode code point. It supports both X11 and Wayland by selecting suitable helper tools for the current session.

  This is free and open source software.

• Excise - interactive terminal storage navigator

  Excise is an interactive terminal storage navigator for understanding where disk space is being used and removing files or directories that are no longer wanted.

  It is an independent fork and spiritual successor to Diskonaut, retaining the visual approach of exploring storage through a map while adding an extensive safety model. Excise distinguishes allocated disk space from apparent file size and treats uncertain values explicitly rather than presenting estimates as exact measurements. Permanent deletion is built into the workflow, but the program deliberately reviews and revalidates targets before making filesystem changes. There is no trash or undo mechanism, so destructive operations are intended to remain visible and deliberate.

  This is free and open source software.

• bitrat - fast multi-algorithm file checksum tool

  Rather than binding the user to a single digest, bitrat supports a broad selection of hashing algorithms. These include BLAKE3, BLAKE2, SHA-3 and SHA-2 families, with the available set exposed through the program’s algorithm-listing command. This makes the tool suitable for workflows where compatibility, performance, or a particular cryptographic primitive determines the required hash.

  The program is designed to make effective use of modern multi-core processors. It uses parallel processing pipelines to calculate checksums efficiently across file collections. HMAC support is also available when a keyed hash is preferable to a plain checksum.

  This is free and open source software.

• OSCAR – comprehensive computer algebra research system

  OSCAR, short for Open Source Computer Algebra Research, is a comprehensive computer algebra system assembled through Julia.

  It presents a common programmable environment for four established mathematical systems: GAP, Polymake, Antic and Singular. Users can combine capabilities that would otherwise live in separate applications, move mathematical objects between supported domains and build reproducible research calculations in ordinary Julia sessions.

  This is free and open source software.

• DRAKVUF Sandbox - agentless malware analysis platform

  DRAKVUF Sandbox is an automated black-box malware analysis platform built around the DRAKVUF virtual machine introspection engine.

  It examines suspicious files in isolated Windows guest systems while keeping the monitoring machinery outside the guest. This agentless approach reduces the instrumentation visible to malware and lets analysts observe behaviour without installing a conventional analysis agent in the target environment. A web interface handles sample submission and presents completed analysis, making the platform useful for malware researchers, incident-response teams and security laboratories that need repeatable behavioural analysis.

  This is free and open source software.

• Zarn - static security analysis for Perl applications

  Zarn is a static application security testing tool aimed specifically at modern Perl codebases. Its purpose is to identify source constructs that may expose an application to security weaknesses rather than enforce formatting conventions or general coding style.

  The analyser parses each source file into an abstract syntax tree, searches for potentially dangerous tokens, and applies taint tracking to determine whether a finding may actually be exploitable. This gives Zarn a more security-focused role than a conventional Perl linter.

  Analysis currently operates within a single-file context. Vulnerabilities whose relevant call path or data flow crosses several files can therefore escape detection. Call-graph analysis is identified as a future development direction.

  Zarn can generate SARIF output, allowing results to be consumed by tools supporting the Static Analysis Results Interchange Format.

  This is free and open source software.

• chibisafe - self-hosted file uploader and file vault

  chibisafe is a self-hosted file uploader and file vault that accepts images, videos, documents and other files and returns shareable links.

  It can operate as a public service, require user accounts, or restrict registration to invitations. A web dashboard gives administrators control over most instance settings, while users can organise uploads into albums and folders and manage their files through the browser.

  This is free and open source software.

• Kleaner - image metadata cleaner

  The application uses a compact KDE Kirigami interface organised around a file list and predefined cleaning templates. Individual entries can be removed before processing, while custom user templates are currently marked as work in progress.

  Internally, Kleaner is built with Qt 5 and KDE Frameworks components including Kirigami and KExiv2. The source combines C++17 with QML, and the application is distributed through Flathub.

  This is free and open source software.

• Eigenmath – compact symbolic mathematics application

  Eigenmath is a compact computer algebra system that brings symbolic manipulation, numerical calculation and mathematical visualization to the command line.

  It can be used interactively from its question-mark prompt or supplied with script files, making it suitable for exploratory work and repeatable calculations. The program is implemented as a self-contained C codebase and builds with make and a C compiler. Its native executable has a deliberately modest build footprint and links against the standard mathematical library.

  This is free and open source software.

• GCLC – mathematical illustrations and automated geometry theorem proving

  GCLC is mathematical software for producing geometry illustrations, teaching mathematics, and automatically proving geometry theorems. It uses its own Geometry Constructions language to describe constructions and can be used through a Qt graphical interface or from the command line. A browser-based version is also available.

  The software combines construction and visualization with automated reasoning. Geometry problems can be processed using several established theorem-proving methods, while generated diagrams and proofs can be exported to formats suitable for documents, presentations, and further processing.

  This is free and open source software.

• Drift – desktop video editor built with Qt 6 and FFmpeg

  Drift is a desktop non-linear video editor built with Qt 6 and FFmpeg. It combines a multitrack timeline with compositing, effects, transitions, audio processing, subtitles and export tools in a single application. Projects can mix video, audio, text, subtitle and shape tracks, while editing operations include trimming, splitting, snapping, ripple editing, speed changes and clip animation.

  The program also offers specialist tools including multicamera editing, scene detection, subject cutouts, face tracking and optional locally installed models for speech and image analysis.

  This is free and open source software.

• Nyxelf - static and dynamic ELF malware analysis

  Nyxelf is a graphical analysis framework for investigating suspicious Linux ELF binaries with static and dynamic techniques.

  It combines established binary-analysis utilities and Python libraries with a custom QEMU sandbox, giving analysts one environment for inspecting executable structure, observing runtime behaviour and translating machine code into more readable forms. The program is aimed specifically at Linux malware and ELF reverse engineering, with a PyWebView interface used to present results. Its dynamic workflow uses a small Buildroot-generated guest image so potentially hostile binaries can be examined away from the analyst’s normal system.

  This is free and open source software.