There are three versions of Neo4j apparently, called Community, Advanced, and Enterprise. Neo4j's Licensing Guide says that Community is GPL3 (which I confirmed from the LICENSE file in the tarball) and the Advanced/Enterprise seems to be dual licensed under AGPL3 and a proprietary license. What exactly does statement of the guide mean?:

If you’re using Neo4j to build closed-source online applications that are central to your business, then you’ll want to talk to us about commercial licensing of Neo4j Advanced or Enterprise editions.

What exactly is meant by a closed source application in the context of server software? Does writing software that merely talks to neo4j over RPC trigger the AGPL under Neo's interpretations? If so, that's vastly differently from how the 10gen treats MongoDB (AGPL).

The above wouldn't be as confusing if it weren't for the following statement:

... you’re free to use the Community edition of Neo4j Server under a GPL license – which means you can use it anywhere you would use something like MySQL. Used in this way, only changes you make to the Neo4j software itself should be open-sourced and shared with the community.

That last sentence is not required of GPL3 software modified for an organization but never distributed and only ever made available as a web application. In fact that's the exact reason AGPL3 was invented, to plug that gap.

Further, the following statement makes no sense since a public domain project is a project without copyright:

We love open source development: so you are free to use all Neo4j components for your open-source, public domain project under either the GPL (for Community edition) or the AGPL (for Advanced and Enterprise).

2 Answers 2


Closed source means the same thing for server-side software as for all other kinds of software: The source code is not available to the users of the software (or only under very restrictive conditions).

If you write software that communicates over a network with other software, then your choice of license for your software is not affected by the copyright license that is used for the remote software you communicate with. (Just think about it, if the AGPL affected the software used to access an AGPL site, users of IE would be in violation of copyright. That can't be right.)
This means that it is no problem to access a service that uses AGPL with a closed-source application.

The (A)GPL license of Neo4j would start to kick in if you make modifications to Neo4j or if your application builds upon Neo4j in the sense that Neo4j is included in your application as a library.

  • 1
    Hi Bart, just to be on the safe side here, could you please clarify once again for me: if I install neo4j on my server and talk to it via API, not touching the source code of neo4j: am I allowed to sell my program/web based application?
    – the.polo
    Jun 6, 2017 at 8:54
  • EDIT: am I allowed to sell my program/web based application as a closed program?
    – the.polo
    Jun 6, 2017 at 9:01
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    @the.polo: Yes, that is allowed to my knowledge. Jun 6, 2017 at 10:36

My reading is that those quotes you provide from the guide are written by someone with a less than perfect grasp of copyright and software licensing issues, and possibly other motivations.

Your rights in using any piece of software not owned by you are strictly governed by the licence you hold for that software. If the actual licence that accompanies the software from an authorised distribution is GPL3 then you are obliged to adhere to the terms of that licence, and nothing you find elsewhere can change that. The licence with the software is the licence for the software.

It's hardly surprising that a commercial organisation will write words that encourage potential users of its sofware to choose a licence that provides them with revenue, rather than one that does not. Those words carry no force as far as licensing is concerned. They might have meaning from a contractual or trade description point of view, but that wasn't the question.

  • @robertH: Why the edit? I don't see the point.
    – david.pfx
    Jul 11, 2014 at 4:23

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