Software Licenses

What Is a Software License?

Software licensing as a type of contract which exists between the person of company who produces a type of software, and the end user, or person who purchases or downloads the software to use. It is created to protect the copyright of the software, and actually restricts the ways in which the end user can utilize it. Most of these restrictions consist of duplicating the software or installing it on more than one computer. Changing the software in any way or editing it’s code is also normally forbidden by the software license.

The software license usually answers questions such as,

• Where and how and how often can you install the program?
• Can you copy, modify, or redistribute it?
• Can you look at the underlying source code?

There are many different types of software licenses, and the penalties for license noncompliance can be harsh. If you reuse a component without following the obligations of its license, the licencor might sue, and you might be forced to publish your own source code. To protect your code and your organization, you need to understand these software licenses before using any code, including libraries and frameworks.

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 adding it to your 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 License and the BSD License, another common variant is the MIT License. LGPL. The GNU Lesser General Public License allows you to lin

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 license 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.

The Apache License

The Apache License is an open source software license released by the Apache Software Foundation (ASF). It’s a popular and widely deployed license backed by a strong community. The Apache License allows you to freely use, modify, and distribute any Apache licensed product. However, while doing so, you’re required to follow the terms of the Apache License.

Microsoft Public Licenses (Ms-PL)

The Microsoft Public License is a free and open source software license released by Microsoft, which wrote it for its projects that were released as open source.

You are free to reproduce and distribute original or derivative works of any software licensed under the Ms-PL license. However, you may not use any contributors’ name, logo, or trademarks when you do so. The Ms-PL protects the authors by explicitly not offering any express warranties or guarantees for using your code, so the author is not liable if the code doesn’t work well in some cases.

MIT License

MIT is one of the most permissive free software licenses. Basically, you can do whatever you want with software licensed under the MIT license — only if you add a copy of the original MIT license and copyright notice to it. Its simplicity is the reason behind its high adoption rate among developers.

Berkeley Software Distribution (BSD)

The BSD License lets you freely modify and distribute your software’s code in the source or binary format as long as you retain a copy of the copyright notice, list of conditions, and the disclaimer.
The original BSD License or the 4-clause BSD License also contains an advertising clause and a non-endorsement clause