Skip to main content
best open source licenses
Software Engineering

The 5 best open source licenses for securing your software rights

Even though you may rarely ever read them (I know I’m guilty), you’re probably familiar with the concept of “terms and conditions” you must agree to before using any software. Regardless of the software, there are strict rules about what you can and can’t do with it – especially when it comes to modifications.

That’s where the open source movement comes in. Open source software is made to be modified and used freely (for the most part). However, just because it has different rules, it doesn’t mean there aren’t any. When building and managing open source projects, developers must choose an open source license to protect their software, and not all licenses are made equal. We’ll take a look at what licenses are best for securing your software rights, but first, let’s look at what open source software is.

What is open source software?

open source licenses

Image sourced from

The idea behind open source software is that people can change or modify the software and that the software is publicly accessible and shareable. You will find multiple open source projects and initiatives online that support the idea of exchanging information and collaborating with others.

Unlike proprietary software (also called closed source), the relevant source code can usually be inspected by anybody. They can then modify or enhance that code if they see where improvements can be made or if they want to tailor the software to particular requirements. Some examples of open source software are LibreOffice, Mozilla Firefox, and freeCodeCamp. You can learn more about how to manage open source projects here.

Why do you normally need a software license?

So you want to release an open source program. You might be thinking, ‘Surely I can just put it out there for free?’

Unfortunately, it’s not that easy! Without using an open source license, others can’t use your work. You need to provide explicit permission. Even if you’ve posted it publicly on GitHub, the most their Terms and Conditions allow is to view and fork your project – not to use, change, or share it.

The two main types of licenses

When you look at open source software licenses, there are two broad categories to consider. The first is copyleft licenses, which require developers to license any modified versions under the same terms as the original version.

The other category is permissive licenses. These allow developers to use the original software in any project they want without licensing any changed versions under the original terms. This allows developers to create a new product based on the original software.

So, if you’re creating software that lets you design a digital business card, you need to ask yourself: do you want others to be able to take that code and implement it into their commercial endeavors? Or do you want to enforce it as being non-commercial and their projects being under the same terms? This will help you choose between a copyleft and a permissive license.

The 5 best open source licenses

1. Berkeley Software Distribution License (BSD)

BSD licenses originated from a Unix-type operating system. They fall under the category of permissive licenses, and there is minimal restriction on how you use and distribute them. This type of license allows you to take an original BSD open source product, then copy it, modify it, and distribute it according to your own needs.

There are two main types of BSD license:

1. the Modified BSD license (3 clauses), which allows you virtually unlimited freedom to change the original product as long as you include the original BSD copyright and license notice.

2. the FreeBSD license which contains 2 clauses referring to what you can do with it.

2. MIT license (Massachusetts Institute of Technology)

The MIT license is another permissive license. It’s been around since the late 1980s, so is very popular with developers who want to change software code to their own needs and create a new product without facing any restrictions or at least minimal restrictions.

One of the main reasons that the MIT license is so popular is that they can modify the code, add to it, and then publish and distribute their own version as well as being able to sell it. If you make things like templates for indemnity agreements or other such software that would work well in a larger context, and you don’t mind other people using your code in commercial projects, then the MIT license is a good choice.

3. GNU General Public License (GNU GPL)

The GNU GPL is a copyleft license and perhaps the most popular of the open source licenses. It guarantees developers the freedom to take a program and modify it in any way they want, as long as they then distribute that altered version as free software. It comes in two slightly different versions, GPLV2 and GPLV3, with the former having a library exclusion that the latter does not.

Developed in 1989 (by Richard Stallman), it was originally designed to protect software developed under the auspices of the GNU Project. If you have a project that you want to ensure remains accessible, even in modified forms, then this license is the one to choose. This license allows your code to be used by anyone while ensuring modified versions are also released as open-source products. That includes making the completely modified source code available to the public.

4. Apache License 2.0

Produced by the Apache Software Foundation (formerly known as the Apache Group), Apache 2.0 is a permissive free software license that is very popular with developers and commercial organizations. As with other permissive licenses, anyone can take the original software and modify it as they see fit, then distribute their modified version under the terms of the original Apache product.

Developers and organizations no longer need to include any attribution to the Apache license if the advertising clause has been removed. Apache 2.0 grants patent rights and carefully defines any concept included in the program itself. For instance, if you designed an email verification program and released it under Apache, a company could incorporate it into a CRM system they sell.

5. Internet Systems Consortium (ISC) License

Similar to the MIT license, the ISC version is a permissive license. It could be described as a ‘stripped-down’ version of the MIT license as it removes some of the language and jargon that some people consider unnecessary. While the language has been changed or removed, it operates on the same functional level as its MIT ‘cousin.’

Like the MIT license, the ISC license has only two requirements for anyone who modifies a program. The first is that anyone who alters the software has to include the original license. The second is that they must include a copy of the license itself when they copy or modify the original licensed code in any new version. Organizations that use the software under an ISC license can use any new code commercially.



Why do I need a software license for open-source projects?

A software license provides explicit permission for others to use, modify, and share your work legally.

What are the main types of open-source licenses?

There are two broad categories: copyleft licenses, which require modifications to be licensed under the same terms, and permissive licenses, which allow for more freedom in using the software.

How do I choose the right open-source license for my project?

Consider how you want others to use your code—whether in commercial projects or to remain open—and select a license that aligns with those goals.


Open source licenses can be of enormous use to developers who want to build something that can be legally iterated on, but still on their own terms. Choosing which open source license best suits their development–and organization’s–needs can be a crucial decision.

Deciding on the type of open source license you need depends on how you wish others to engage with your code. If you want them to be able to modify it and use it commercially, then it’s best to choose a permissive program that allows the distribution and selling of a modified program. However, if you want to make something simple that remains publicly accessible even when modified, you’ll want one of the copyleft licenses.

Ready to start your open source project? Try managing it in Zenhub with a free 14-day trial here.

About the author

Yauhen Zaremba – Director of Demand Generation

Yauhen is the Director of Demand Generation at PandaDoc, all-in-one document management tool for almost all types of documents including the PandaDoc rental lease agreement template. He’s been a marketer for 10+ years, and for the last five years, he’s been entirely focused on the electronic signature, proposal, and document management markets. Yauhen has experience speaking at niche conferences where he enjoys sharing his expertise with other curious marketers. And in his spare time, he is an avid fisherman and takes nearly 20 fishing trips every year.

Share this article

Work smarter, not harder. With Zenhub AI

Simplified agile processes. Faster task management. All powered by AI.

Get Early Access

Hone your skills with a bi-weekly email course. Subscribe to Zenhub’s newsletter.

Return to top