Open Source License Types: A Complete Guide
It’s not just the software buyers and the budding developers who misunderstand the meaning of the term “Open Source”. Most people presume Open Source for something that lets you use, copy, alter, and distribute software as desired and necessary.
As seen and observed, this confusion is often derived from public domains or shareware that are free to use and comes without these comprehending words - Terms and Conditions Applied. And this is exactly where Open Source License Types come in.
The fact is that open source software comes layered with multiple types of open source licenses. And there are different types of open source licenses like Copyleft License and Permissive License.
Disclaimer: This post is meant to be informational, and is geared towards enabling software development teams to have a better understanding of the open-source licensing framework. It is not meant as legal advice
What Is An Open Source License?
An Open Source License is a type of license that allows users to freely view, modify, and share the source material of the software. This way, users are able to frequently update the source code and build on the original product.
Depending on the Open Source License type chosen, users may or may not be able to do certain activities with the code, such as selling it or using it commercially. In addition, there are many different types of Open Source Licenses out there, each offering different terms and conditions depending on how you want to use the source material.
Therefore, it's important to fully understand an Open Source License type before taking advantage of its benefits, so be sure to read up more below before making any decisions.
Types Of Open Source Licenses
Open Source Licenses come in types to choose from, depending on your project's needs. However, they can be categorized into two most common types. They are:
1. Permissive Licenses
Permissive licenses in open source licenses, often referred to as 'liberal or 'Apache-style' licenses, provide developers with the greatest level of freedom. This kind of license does NOT require thing like:
Typically these licenses also contain fewer restrictions on use and distribution than other open source licenses; they may forbid certain kinds of modification of the original software but do not generally require attribution or notice when modifications have been made.
Many popular open source applications operate under permissive licenses such as MIT License and Apache License 2.0, allowing users to make use of them without worrying about any potential legal issues arising from altering your code base and distributing modified versions.
2. Copyleft Licenses
Copyleft licenses in open source provide the user of the open-source software with the author's freedom to modify, use, and redistribute the software. However, it requires users to pass on specific rights to other users downstream by granting them the same rights that were originally given to them.
Copyleft licenses define how redistribution and changes to the code are allowed, prohibiting any attempts at making it proprietary or non-open. This ensures that developers modifying the software have access to the source code to update it or even incorporate their own changes. Of course, any modifications must also be made available so others can benefit from its open source availability. This is a non-issue for academic or research use-cases, but is often a deal breaker when building commercial software.
Popular Permissive Software Licenses
Permissive software licenses are among the most popular. In essence, these licenses allow users to modify and redistribute the software as they please, with minimal restrictions. Three of the most popular versions of permissive software licenses are:
MIT License
The MIT License is the most popular and permissive open source software licenses. It provides users with notable freedoms, including allowing them to freely share, modify, use, and commercialize the material if they adhere to all the conditions set forth in the license.
Its most attractive element is the "no additional restrictions" clause – users are free to modify and redistribute derivatives of the original code as much as they wish so long as they acknowledge it following original copyright law. The MIT License has been adopted by thousands of open-source projects and software products due to its simplicity and generous terms, making it a reliable tool for widespread sharing.
Apache License 2.0
The Apache License 2.0 is a popular permissive software license that enables users to freely modify and redistribute the software while having the assurance that the resulting copyright statements and notices are kept in primary form. This open-source license allows proprietary modifications and redistribution and provides clear licensing terms so anyone can understand their rights when using the software.
It places minimal restrictions on what you can do with the code, adding only a few basic conditions for use without restricting further development or distribution. The Apache License 2.0 does not contain any payment or royalty liabilities provisions, rendering it an ideal choice for commercial applications where owners want their product to stay open source.
BSD (Berkeley Software Distribution) License
The BSD (Berkeley Software Distribution) License is one of the most popular, permissive software licenses widely adopted by developers worldwide. It was first used in the BSD operating systems and is one of the earliest open source software licenses. The key feature of this license is that it allows users to copy, modify and redistribute the software, as long as they provide copyright notice and disclaimer of warranty - two obligations that are compliant with other open-source licenses.
There are no restrictions on selling the software or using it for commercial purposes, nor does the author require any form of compensation for its use. This ensures that anyone can create and build upon existing software projects without worrying about legal repercussions such as copyright infringement. Ultimately, this makes collaboration within the developer community much easier-- allowing developers to produce great software projects.
Popular Copyleft Software Licenses
Software copyleft is a type of licensing in which users are given the freedom to run, modify, and distribute software however they please, as long as the original source code is kept intact. The two most popular copyleft licenses are:
GPL License
When it comes to copyleft software licenses, the GPL (General Public License) is one of the most popular and widely used. This open-source license grants users the freedom to distribute copies and modified versions of a program as long as they retain certain conditions, such as copyright notices, warranty disclaimers, or any other licenses that have been added to the unmodified Program.
By making software available with this license type, developers are ensuring that others have access to their source code, allowing them to make improvements and adaptations that benefit the community. In addition, this concept of "copyleft" ensures that anyone can collaboratively share the same freedoms when working with free software.
Mozilla Public License 2.0
The Mozilla Public License (MPL) 2.0 is a copyleft software license that offers both users and developers great flexibility when it comes to using, distributing, and modifying the code of open source software. It combines the strong protection of copyleft licenses with practical logistics, which makes it easier to share code within parts of an existing project without creating a restrictive environment for others.
The MPL grants recipients the right to modify, extend and distribute licensed files while only requiring that any changes they make and redistribute must also be released under MPL 2.0. This gives people a chance to monetize their work but still keep its benefits available for free elsewhere in the ecosystem.
How Can You Choose The Correct License For Your Project?
Choosing a license for your project can be a daunting task, but it is an important factor in the success of your work. Knowing which license is right for you and your project includes a variety of factors, such as its intended use, the type of software you are using, whether you will be sued or sue someone else for the project's usage, and other technological considerations.
To select an appropriate license under different circumstances, start with these suggested steps
1. If you're releasing your project under an open source license, choose a license compatible with the projects you're using.
2. If you want to allow others to use your project for commercial purposes, choose a license that permits this.
3. If you want to allow others to modify and distribute your project, choose a license that permits this.
4. If you want to ensure that your project remains free and open source, choose a copyleft license.
Ultimately, when selecting a license, it is important to find one that fits well within the specific context of your project. Choosing the correct license for your project can be fast and easy with proper attention and research.
How Can Licenses of other Open-Source Projects affect You?
Most software developers do not create projects from scratch, and generally do not have to worry about distribution and modification concerns with regards to the code they write. However, they still need to be mindful of the licenses of the open-source libraries they use.
For example, using the popular Maven library itext for PDF generation can greatly speed up the development of a PDF reporting functionality. However, the library is licenses under and AGPL license, which means all derivate works would need to open-sourced. If your code is proprietary (for example, you are writing coding at your job, or as a vendor for a software development project), you would be in violation of the license and may be subject to litigation and/or licensing fees.
As a software developer, you must always use open-source components that are licensed as per the approved open-source policy of your organization.
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