A software license is a legally binding agreement between a software creator/owner and the end-user, defining how the product can be used, shared, or modified. It acts as a contract protecting intellectual property rights, outlining user responsibilities, and setting terms for installation, redistribution, and liability.

There are 2 main types of licence:

Proprietary: includes commercial, subscription, freeware and shareware

Open source: source code is available to view, use, modify, and distribute under an open licence (e.g. Linux, Python)

This type of license restricts users from accessing the source code of the software and often limits how the software can be used. Users typically receive the compiled program, and they must abide by the terms and conditions set by the software's owner.

Pros

• Proprietary licenses ensure that the software owner retains full control over how the software is used

Cons

• Proprietary licenses restrict user flexibility by not allowing access to the software’s source code.
• Users are usually required to pay for the software, which may make it less accessible for some individuals or organizations.

Open source licenses grant users the right to view, modify, and distribute the source code of the software freely. There are various open source licenses, including the GNU General Public License (GPL), Apache License, and MIT License, each with its own terms and conditions.

Pros

• Open source licenses encourage collaboration and innovation by allowing users to view, modify, and distribute the source code.
• They promote transparency and community-driven development.

Cons

• Open source software may not come with dedicated support or warranties, making it harder for users to resolve issues..

Permissive licenses, such as the MIT License and the Apache License, allow users to modify and distribute the software under relatively lenient terms. Users can incorporate permissively licensed code into their projects, even proprietary ones, without significant restrictions.

Pros

• Permissive licenses are highly flexible and allow integration into both open source and proprietary projects.

Cons

• Permissive licenses provide limited protection against misuse, allowing others to use or commercialize derivative works without much restriction.
• This can result in the original creator losing some control over their software.

Commercial licenses are typically used for proprietary software and require users to purchase a license or pay a fee for specific uses. These licenses often provide additional features, support, or warranties in exchange for payment.

There are different types of commerical licence but they include:

• Single user licenses
• Multi-user licences
• Site licences
• Muli-seat licences

Freeware & Shareware  licenses allow users to use the software for free, but they may have restrictions on distribution, modification, or commercial use. It also often lacks advanced features, updates, or dedicated technical support.

They often allow users to try the software for free before requiring payment for continued use or access to additional features.

Continued use or access to full features often requires payment after the trial period ends. Shareware versions may also limit functionality compared to the full paid version.

Software in the public domain is not protected by copyright, allowing anyone to use, modify, and distribute it freely without restrictions. It promotes open access and creativity without any legal limitations.

Public domain software however comes with no support, warranties, or guarantees. The lack of control over derivative works may result in misuse or unintended consequences.

Also known as a single-seat license or individual license, is a software licensing arrangement that grants the right to install and use a software application on a single computer or device, typically for a single user.

In most cases, single-user licenses are non-transferable, meaning the license cannot be shared, resold, or used by multiple individuals on different devices. 

Single-user licenses are often associated with software intended for personal or individual use, such as productivity software (e.g., Microsoft Office), creative applications (e.g., Adobe Photoshop), or specialized tools (e.g., accounting software).

A multi-user license, sometimes referred to as a concurrent license, allows a specified number of users to access and use a software application simultaneously.

The number of users permitted under the license is defined in the agreement, and when that limit is reached, additional users cannot access the software until existing users log out.

A site license is a software licensing agreement that grants an organization or institution the right to use a particular software product on an unlimited number of computers or for an unrestricted number of users within a single physical location or site.

Site licenses are often employed by educational institutions, government agencies, and large enterprises to provide widespread access to software applications while simplifying management and reducing costs.

A multi-seat license, often referred to as a concurrent or shared license, enables multiple users to access and use a software application. However, the number of users who can use the software at the same time is limited to a specified number defined in the licensing agreement.

When the maximum number of concurrent users is reached, any additional users attempting to access the software must wait until an active user logs out or releases their session.

These licenses are often offered to educational institutions, students, or researchers, allowing them to use the software for educational or research purposes under specific terms and conditions.