In the last four years, I made over $350K from a simple JavaScript library called lightGallery using a dual-licensing business model. Here is everything you need to know about monetizing your commercial open-source software (COSS) project using dual licensing. What is the dual-licensing business model? It is a proven commercial open-source strategy where you offer your software under two different licenses: A free, copyleft open-source license (GPL or AGPLv3) A paid, commercial license for proprietary use When software is dual-licensed, users can choose the legal terms under which they want to use the software. How does this work? If a developer chooses the free GPL license and includes that code in their project, as per GPL terms, they are often required to open-source their entire project. For instance, if a company uses your GPL-licensed JavaScript on their website, the viral nature of the license may require them to release their entire website’s source code. Most enterprise companies cannot do this.…