ERPNext is the most popular 100% open source ERP system in the world. https://erpnext.com/
There is hidden code. Entire code is available on GitHub. ( https://github.com/frappe/erpnext ) Anyone can download the code and use it. The code is released on GPLV3, which allow anyone to download, use, and customize the code. https://www.gnu.org/licenses/gpl-3.0.en.html
There is dedicated support team from Frappe to support the code, which include upgrades, new editions, bug fixing, and security patches.
Claudion has dedicated team to support ERPNext customization, Arabic support and other localizations. Claudion also works on the same GPL V3 and share the code with the world. Our source code also published regularly on the Gib ( https://www.gnu.org/licenses/gpl-3.0.en.html )
ERPNext rated as top-performing softwares by GetApp .
More than 5000 companies across the world use ERPNext for mission critical ERP system.
Best and easy user interface and modules cover all aspects of the business are two main reasons attracting clients all over the world to ERPNext.
You can always contact our support team on on email@example.com