Kai A. Hartung

Kai A. Hartung

Apache License 2.0

The Apache 2.0 is a modern permissive license favored by large enterprises (Google, Android, Kubernetes). Like MIT, it allows full commercial use. Crucially, it includes an explicit patent grant, protecting you from patent lawsuits from the contributors.

BSD 3-Clause License

The BSD 3-Clause License (also known as "New BSD" or "Modified BSD") is a permissive free software license. It is very similar to the MIT License, allowing you to use, modify, and distribute the software for any purpose. The key difference is an added clause that prohibits using the nam...

GNU LGPL v3

The LGPL (Lesser General Public License) is a compromise between the permissive Apache/MIT and the strict GPL. It allows you to link your proprietary software to an LGPL library (dynamically) without forcing your proprietary code to become open source. However, if you modify the LGPL li...

GNU GPL v2

The GPL v2 is the classic "Copyleft" license (Linux Kernel). It ensures that if you distribute the software, you must provide the source code. Unlike v3, it does not explicitly address "Tivoization" (locking hardware) or patent grants as aggressively.

GNU GPL v3

The GPL v3 is a "Copyleft" license. It guarantees freedom for the end-user, not the developer. If you distribute software that links to GPL code, your entire application must also be released as open source under GPL.

GNU AGPL v3

The Affero GPL (AGPL) is designed to close the "SaaS Loophole." Unlike standard GPL, if you run AGPL software on a server and users interact with it over a network (e.g., a website), you MUST share your source code with them if you modified the software.

SSPL (Server Side Public License)

The Server Side Public License (SSPL) is not an official Open Source license. Created by MongoDB, it allows you to use the software freely, but forbids you from offering it as a "Managed Service" (e.g., you cannot launch "MyHostedMongoDB" and charge for it).

Functional Source License (FSL)

The Functional Source License (FSL) is a modern "Source Available" license pioneered by Sentry. It grants developers the right to copy, modify, and redistribute the code for any purpose except providing a competing commercial service. It is NOT an Open Source license (OSI definition) du...

Business Source License 1.1 (BSL)

The Business Source License (BSL or BUSL) is a "Source Available" license, NOT an Open Source license (according to OSI definitions). It allows users to copy, modify, and redistribute the code for non-production or limited production use, but typically restricts "competing" commercial u...

Elastic License 2.0 (ELv2)

The Elastic License 2.0 (ELv2) is a non-copyleft "Source Available" license created by Elastic (the company behind Elasticsearch). It is NOT an Open Source license by the OSI definition. It was designed to protect software creators from "SaaS-jacking" by large cloud providers while keep...

Sustainable Use License (Fair Code)

The Sustainable Use License (often associated with the "Fair Code" movement) is a "Source Available" license, not a strictly Open Source license (OSI definition). It grants you broad rights to view, modify, and use the software for free—with one critical restriction.

Browser-Based / Local-First

Browser-Based (Local-First) solutions run entirely inside your web browser. There is no server installation, no login, and often no backend database. The application code is downloaded once, but all data creation and processing happen locally on your device.

Managed SaaS

Managed SaaS means the Open Source creator hosts the software for you. You pay a monthly subscription fee instead of managing servers. This is the "Easy Button" for enterprises who have budget but no time.

Extension / Plugin

Extensions (or Plugins) are small software modules that live inside another host application, most commonly a Web Browser (Chrome/Firefox/Edge) or an IDE (VS Code).

Mobile Application

Mobile Applications are native software installed on smartphones (iOS/Android). In Open Source, these are distributed via standard App Stores or privacy-focused repositories like F-Droid.

Language Runtime (Pip/NPM)

Runtime Deployment means installing the application as a library or package using a language-specific manager (like Pip for Python, NPM for Node.js, or Composer for PHP).

Native System (Binary/Linux)

Native Deployment involves running the software directly on the Operating System, either as a Single Binary (common in Go/Rust) or via a system package manager (DEB/RPM). This is the "Bare Metal" approach.

Docker Container

Docker Deployment is the industry standard for self-hosting software. The application comes pre-packaged in a "Container" with all its dependencies included. It runs reliably on any standard server (Linux/Windows) without conflicts.

LAMP Stack (Linux, Apache, MySQL, PHP)

The LAMP Stack is the grandfather of the modern web. It stands for Linux (OS), Apache (Web Server), MySQL (Database), and PHP (Language). It powered the Web 2.0 revolution (WordPress, Drupal, PrestaShop) and remains the most common hosting environment globally.