Software Licensing
What is Software Licensing?
A software licence is a legal instrument governing the use or redistribution of software. Under United States copyright law, all software is copyright protected, in both source code and object code forms, unless that software was developed by the United States Government, in which case it cannot be copyrighted. Authors of copyrighted software can donate their software to the public domain, in which case it is also not covered by copyright and, as a result, cannot be licensed.
A typical software license grants the licensee, typical and end-user permission to use one or more copies of software in ways where such a use would otherwise potentially constitute copyright infringement of the software owner’s exclusive rights under copyright.
Different types of Software Licensing
Different types of software licenses require you to meet certain obligations if you want to reuse the code. Here are 5 common types of software licences.
If you write code, you also reuse code, including code snippets, libraries, functions, frameworks, and entire applications. All software code comes with certain rights and obligations if you want to add it to your codebase. Free and open source software (FOSS) is free of cost, but you aren’t free to user it as you wish. Even unlicensed code snippets copied from Stack Overflow have obligations for reuse. But formally developed code usually comes with a specific software license.
Public domain
This is the most permissive type of software license. When software is in the public domain, anyone can modify and use the software without any restrictions. But you should always make sure it’s secure before addign it to you own codebase. Warning: Code that doesn’t have an explicit license is NOT automatically in the public domain. This includes code snippets you find on the internet.
Permissive
Permissive licenses are also known as “Apache style” or “BSD style.” They contain minimal requirements about how the software can be modified or redistributed. This type of software license is perhaps the most popular license used with free and open source software. Aside from the Apache Licence and the BSD License, another common variant is the MIT License.
LGPL
The GNU lesser General Public License allows you to link to open source libraries in your software. if you simply compile or link an LGPL-licensed library with your own code, you can release your application under any licence you want, even a proprietary license. But if you modify the library or copy parts of it into your code, you’ll have to release your application under similar terms as the LGPL.
Copyleft
Copyleft licenses are also known as reciprocal licenses or restrictive licenses. The most well-known example of a copyleft or reciprocal license is the GPL. These licenses allow you to modify the licensed code and distribute new works based on it, as long as you distribute any new works or adaptations under the same software license. For example, a component’s license might say the work is free to use and distribute for personal use only. So any derivative you create would also be limited to personal use only.
Proprietary
All types of software licenses, this is the most restrictive. The idea behind it is that all rights are reserved. It’s generally used for proprietary software where the work may not be modified or redistributed.
