The MIT License is the most permissive and popular open-source license. It allows you to use, copy, modify, merge, publish, distribute, sublicense, and sell the software. The only requirement is that you include the original copyright notice in your copy.
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.
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...
The Mozilla Public License 2.0 (MPL-2.0) is the "middle ground" of open source licenses. It is a weak copyleft license.
The EPL-2.0 is a business-friendly, weak copyleft license. It allows for proprietary integration while ensuring that modifications to the original files remain open source.
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...
The Open Software License 3.0 (OSL-3.0) is a strong copyleft license, often compared to the AGPL but with distinct legal mechanisms.
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.
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.
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.
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).
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...
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...
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...
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.
Strategic intelligence entry regarding Custom License. Part of the OpenTechHub Strategic Playbook.