Linux Foundation Says Yes To Nosql Via Documentdb

The Linux Foundation on Monday welcomed Microsoft’s DocumentDB into its stable of open source projects, waving the document database’s permissive MIT license as if it were an “Open for Business” sign.

The project adoption represents a response to MongoDB’s 2018 decision to switch to the Server Side Public License (SSPL), which requires cloud providers to release service-related source code, something they’re generally loath to do. 

In the past decade, those attempting to build companies atop open source projects have often adopted somewhat restrictive software licenses that try to limit the ability of cloud giants (AWS, Google, Microsoft, etc) to offer competing services. Who wants a hyperscaler with huge market advantages using your own code to beat you?

More restrictive licenses like the SSPL, which don’t qualify as open source under the OSI definition, are not particularly popular or enduring. Redis, for example, recently abandoned it and adopted the more permissive AGPL license instead after the Linux Foundation and a group of vendors planned to offer a forked version of Redis, Valkey, under a more permissive license. (The AGPL, while a FOSS license, comes with more obligations than the laissez-faire MIT license – it’s kind of a middle ground between the two.) Grafana and Elastic have also added the AGPL as an option, though SSPL 1.0 and the similarly restrictive Elastic License 2.0 remain options.

Microsoft began developing DocumentDB in 2024 as a set of PostgreSQL extensions for Binary JavaScript Object Notation (BSON) data models and MongoDB-compatible create, read, update, and delete (CRUD) operations. The idea is to implement a NoSQL datastore using PostgreSQL, an open source object-relational database system.

Relational (SQL) and non-relational (NoSQL) databases rely on different techniques for data storage. The former depends upon a schema, uses structured query language (SQL), and makes atomicity, consistency, isolation, and durability (ACID) guarantees. The latter stores unstructured or semi-structured data using key-value pairs or JSON, offering high performance with less ACID assurance. As The Register has noted previously, DocumentDB brings the two approaches closer together.

When it announced the official release of DocumentDB in January, Microsoft made a point of differentiating the project’s permissive MIT license from the SSPL.

“While contributions to the project are always welcome and encouraged, there are no requirements for users to commit their customizations, contributions, and enhancements back to the project,” said Abinav Rameesh, principal program manager for Microsoft Azure Cosmos DB. “The MIT license guarantees complete freedom to fork the repository, use, and distribute with no obligations.”

DocumentDB could be viewed as the successful outcome of an earlier rebellion against MongoDB’s licensing practices. In 2023, startup FerretDB released FerretDB 1.0 to provide a PostgreSQL alternative for MongoDB and rallied the Document Database Community to develop a standard query language, similar to SQL for relational databases, that works across document databases.

In a post to LinkedIn on Monday, FerretDB CEO and co-founder Peter Farkas recounted a MongoDB exec threatening them for creating a compatible product – litigation that commenced as a patent lawsuit [PDF] in May 2025.

“Being called a thief by a leader of a (then) $35B company was a moment of stark clarity on MongoDB’s opinion about our work and the need for a standard,” he wrote. “At the end of that call, I told them the industry would inevitably come together to create the open standard they refused to provide.”

Farkas said Mongo’s VP dismissed that scenario.

“Today, the market has spoken,” Farkas wrote on Tuesday. “The Linux Foundation has announced the adoption of the DocumentDB project to create an open standard with MongoDB compatibility, the exact thing we were sued for earlier this year.”

Microsoft VP Kirill Gavrylyuk said in a statement that the company developed DocumentDB to provide developers with an open document database that combined the flexibility of NoSQL with the reliability, openness, and ecosystem of Postgres.

“In just a few months, the community has embraced the project,” said Gavrylyuk. “By joining the Linux Foundation, we’re deepening our commitment to transparency, open governance, and developer-first principles – ensuring DocumentDB remains an open, extensible document database developers can confidently build on for years to come.”

In a statement provided after publication, a MongoDB spokesperson said, “After years of parallel attempts in the market, Microsoft has now chosen to move stewardship of its document database service to the community. However, the service still relies upon Postgres and still has all the disadvantages of a relational database. This underscores the challenges of retrofitting infrastructure that was not built for a true document database.

“MongoDB believes in open source approaches that respect innovation and support sustainable businesses. Our broader partnership with Microsoft has never been stronger.” ®

Original Source