GPL only applicable for frontend, or backend too?



We are planning to build a web app based on DHTMLX.

The backend is written in Java. This Java backend is delivering HTML + Javascript as frontend to end-users and interacting with some Ajax calls that this frontend makes.

The license terms for DHTMLX are GPL and in our opinion we respect the most critical requirements. End-users get the HTML + Javascript source code directly on their browser as source code.

Since there is a well-defined API that separates the backend from the frontend, this frontend is only a client implementation that can be replaced with any other and GPL will be out of scope for the backend as mentioned on

Would you agree that on this case the backend can have whatever license decided and the frontend will be GPL?

Many thanks


From our understanding, if the client-side part communicates with the server side only via a strictly-defined API and can be easily replaced with any other frontend implementation, client-side and server-side code can be considered as separate programs. And in this case, the server side doesn’t have to be licensed under GNU GPL.
However, it’s only our point of view and we don’t provide any guarantees or legal protection. The end users of your app can have another opinion on this matter so we recommend you to consult with a lawyer first. Or you can simply purchase a Commercial license and exclude possible complications.