Best Free and Open Source Software

posted by Rianne Schestowitz on Oct 04, 2026

• Syntax Tree - Ruby formatter and syntax tree toolkit

  Syntax Tree is a toolkit for parsing, inspecting, transforming and formatting Ruby source code. Rather than being limited to producing consistently styled source, it represents Ruby programs as syntax trees that other development tools can inspect and manipulate.

  This wider scope makes Syntax Tree useful both as an end-user formatter and as infrastructure for programmers building source-code tooling. It exposes its functionality through a command-line interface and Ruby APIs, with facilities covering structural inspection, transformation, searching and editor integration.

  This is free and open source software.

• Arid - fast duplicate-code checker for Python

  Arid is a command-line tool that detects duplicated source code in Python projects.

  It provides a focused alternative to Pylint’s R0801 duplicate-code checker and is intended to complement broader tools such as Ruff. Arid analyses Python syntax rather than simply comparing raw text, allowing it to identify duplicate blocks while retaining accurate locations in the original source. It can be used interactively during development or incorporated into automated quality checks.

  This is free and open source software.

• Hello Contest - amateur radio contest logger

  Hello Contest is a graphical amateur radio contest logger with a particular emphasis on CW operation on the HF bands.

  Its workflow is designed around rapid keyboard-driven entry during a contest, when reducing unnecessary interaction with the mouse can make logging considerably more efficient. Contest definitions supply the scoring rules while the application combines logging with radio integration, callsign information and operating aids. The interface is built with Qt and the application stores its log data using Protocol Buffers.

  This is free and open source software.

• Palpo - high-performance Matrix homeserver

  The server uses PostgreSQL for data storage and the Salvo asynchronous web framework. PostgreSQL provides familiar database administration, backup and replication facilities, while allowing storage to be managed independently from the application. Palpo also employs caching and database query optimisations to reduce resource usage.

  Palpo supports Matrix federation and is tested with the Matrix Complement end-to-end test suite. Deployment options include building directly from source or using Docker containers. The project targets Linux as well as macOS and Windows through WSL2.

  This is free and open source software.

• DNSViz - analyse and visualise DNS and DNSSEC behaviour

  The suite separates data collection from interpretation. A domain can first be probed and the raw results saved as JSON, then assessed or rendered later without repeating the network queries. This workflow is useful for troubleshooting live DNS configurations, examining DNSSEC validation chains, and testing proposed changes before they are deployed publicly. Stored probe data can also be reused to generate different forms of output without querying the target again.

  This is free and open source software.

• 4 Best Free and Open Source PKI and Certificate Authority Tools

  PKI is widely used for securing websites and network services, authenticating users and devices, encrypting communications, signing software and protecting software supply chains. It is particularly important in environments where systems need a reliable way to prove identity or verify that data has not been altered.

  These tools are used by system administrators, security engineers, DevOps teams, software developers, infrastructure operators and organisations running internal or public services. They range from utilities suited to individual projects to components used in large-scale automated security infrastructure.

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

• Pardus Parental Control - manage application, website and session restrictions

  The GTK4 interface provides separate controls for application filtering, domain filtering and session limits. Application and domain rules can operate as either allowlists or denylists. This makes it possible to block a small selection of resources or restrict a user to an explicitly approved set.

  Application restrictions are enforced using file permissions and malcontent, while website filtering uses smartdns-rs together with managed browser policies. Session limits are enforced by a privileged daemon, with permitted hours and daily usage limits configurable for individual weekdays.

  This is free and open source software.

• goimports-reviser - Sort and Format Go Imports

  goimports-reviser is a command-line tool for organising imports in Go source code according to configurable grouping rules. It distinguishes standard-library imports from general dependencies, project dependencies, and optional company-specific packages, giving projects more control over import layout than a simple alphabetical pass.

  The program can also perform source formatting, allowing import organisation and code cleanup to be combined in one workflow. It accepts individual files, directories, recursive targets, and multiple paths, making it suitable for editor integration and repository-wide checks.

  This is free and open source software.

• MySQL Shell - advanced client and administration console

  MySQL Shell is an advanced interactive client for developing, administering and maintaining MySQL systems. It goes considerably beyond the traditional command-line client by combining an interactive SQL environment with scripting interfaces and specialised administration APIs.

  The shell can be used interactively by database administrators or incorporated into repeatable scripts. Its utilities cover common operational jobs such as copying databases, logical backups, restores, migration assessment and management of highly available deployments, making it suitable for both individual servers and more complex MySQL environments.

  This is free and open source software.

• Emacs Solo - built-in focused modular Emacs configuration

  Emacs Solo is a complete Emacs configuration built around the idea of using the editor’s own facilities wherever practical instead of assembling a large collection of third-party packages.

  The configuration is intentionally educational as well as usable. Much of its functionality is implemented directly in Emacs Lisp, giving users examples they can inspect, modify or lift into their own configuration. Although extensive, it is organised into reusable sections covering editing, navigation, development, file management and desktop integration.

  This is free and open source software.