MongoDB has both free (as in price) and paid versions and there will be no changes to the terms for using the free version unless one is using it as a service – as big cloud providers like AWS do.
Elliott Horowitz, the chief technology officer and co-founder of MongoDB, said in a statement that the new licence, the SSPL, had been submitted to the Open Source Initiative for certification as an open source licence.
The SSPL will make it mandatory for anyone who uses MongoDB as a service to either release the source code of the application that runs it, or else take out a paid subscription. The new licence will cover all future versions of MongoDB and also patch releases to prior versions made after 16 October.
Horowitz said the best existing solution for a company that was releasing open source software — and did not want to provide free use as a service — was to license it under the AGPL – the Affero General Public Licence.
"This approach was believed to be good enough, as most people understood their obligations to comply with AGPL," he said.
"However, as AGPL-licensed software like MongoDB has become more popular, organisations like the international cloud providers have begun to test the boundaries of this licence. We would prefer to avoid litigation to defend the AGPL, but instead devote our time to build great products for the community and our customers."
Horowitz said since MongoDB owned 100% of the software's copyright, the company could have converted its licence to a proprietary one.
"We chose not to because we fundamentally believe in open source software," he said. "We believe an open source approach leads to more valuable, robust, and secure software, and it directly enables a stronger community and better products.
"We also could have licensed most of the code for the MongoDB server as AGPL while applying a closed licence to some critical files. We chose not to do that because we believe that a uniform licensing approach, where all the code in a repository shares a single licence, makes it easier to understand the obligations of using that code, leading to a stronger development community."
One Debian GNU/Linux developer, Chris Lamb, has set up a two-man team to fork modules that add functionality to Redis, after the company put the modules under the Commons Clause and started to charge for them.
His little project to provide open-source versions of the modules in question has been started along with Nathan Scott, a developer at the Fedora project, a community GNU/Linux distribution sponsored by Red Hat.