closed source

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Closed source is a term used to describe software whose source code is not available to the public. Unlike open source software, closed source software does not allow users to copy, delete, or modify parts of the source code. Doing so can result in minor to severe consequences, such as voiding warranty, legal actions, etc.

Use Cases and Examples

Closed source software is also known as proprietary software or non-free software. Usually, vendors limit the number of computers on which such software can run. They can enforce it by employing different tactics, such as product activation, serial number, product key, etc.

Some examples of closed source software include Skype, Adobe Reader, Windows, Microsoft Office, mac OS, Google Earth, etc. Other than distributing the software without the source code, some are vendors that sometimes provide the source code to their customers. For example, customers of vBulletin (an internet forum software) who have purchased a license, get access to the source code. They can modify the source code for their site, but they are not allowed to redistribute it. This kind of model is usually employed if the software is based on an interpreted language where the source code is needed to be able to run the software.


Closed source software is dependent on the developers, as they are the ones responsible for more software advancements, features addition, and bugs fixes. It is in their hands to either continue the future development or not.

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