ERPNext is Open Source under the GNU General Public Licence v3 and has been listed as one of the Best Open Source Softwares in the world by many online blogs.
You're encouraged to help improve the quality of this documentation, by sending a pull request on the GitHub Repository. If you would like to have a discussion regarding the documentation, you can do so at the forum.
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ERPNext is used by more than 5000 companies across the world.