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Redis has recently announced a change in their license by transitioning from the open-source BSD to the more restrictive Server Side Public License (SSPLv1). The move has promptly led to a fork initiated by former maintainers and reignited discussions surrounding the sustainability of open-source initiatives.

Starting with Redis 7.4, all subsequent versions will be dual-licensed under the Redis Source Available License (RSALv2) and SSPLv1, foregoing distribution under an approved open-source license. Rowan Trollope, CEO of Redis, explains:

The new source-available licenses allow us to sustainably provide permissive use of our source code (…) Under the new license, cloud service providers hosting Redis offerings will no longer be permitted to use the source code of Redis free of charge.

Started in 2009 by Salvatore Sanfilippo, Redis has emerged as the most popular in-memory storage solution, used as a distributed, in-memory key–value database and cache. With the adoption of the more restrictive SSPL license created by MongoDB, Redis will not be an open-source project anymore. In a follow-up article to address some of the concerns, Trollope and Yiftach Shoolman, co-founder and president at Redis, address some of the concerns and announce new features:

We’re going back to our roots as the world’s fastest real-time data platform and are proud to announce the acquisition of Speedb, the world’s fastest data storage engine. Over the past two years, we’ve been working directly with Speedb, integrating it as the default storage engine in the Redis Enterprise auto-tiering functionality launched recently in version 7.2.

Reflecting on Redis’s journey, Khawaja Shams, co-founder and CEO at Momento, and Tony Valderrama, head of product at Momento, argue that “Redis did not create Redis” and “how Garantia Data pulled off the biggest heist in open source history.”

The licensing transition has raised concerns in the community and Madelyn Olson, principal engineer at Amazon ElastiCache and formerly a member of the Redis open source governance, writes:

I’ve gotten together with various former Redis contributors and we’ve started working on a fork. We are all unhappy with the license change and are looking to build a new truly open community to fill the void left by Redis. Come join us!

Similar changes in licenses by ElasticSearch triggered official forks from AWS, with the cloud provider recently building GLIDE, a new Redis client. To provide clarity on the new project, Olson clarifies:

Is this an AWS fork? AWS employs me, but this is just me trying to keep the continuity with the community. AWS is aware of what I’m doing and is preparing their own response.

Werner Vogels, CTO at Amazon, adds:

I am excited about the actions Madelyn Olson and other core Redis maintainers are taking. BTW, this is Madelyn taking action, not an official AWS announcement. She should get serious credit for her bias for action. Expect more news soon.

The new license applies to the upcoming 7.4 release, with all previous versions continuing to be open-source under the BSD license.