Should You Trust Redis’s Rebaptism Into the Holy Open Source Spirit?

Be sure to take the included poll after you read this delve into Redis and the wishy-washy world that has become the company’s relationship with open-source.

Somewhere out there I’m sure there are former Redis customers — or even current customers who’ve made plans to adopt a Valkey-based solution — who might be seriously considering returning or staying with Redis now that the company has seen the error of its ways and is reinstating open-source licensing. If so, I would advise them to think long and hard before doing so.

Redis, if you don’t know, is an in-memory, NoSQL database that’s popular among enterprise DevOps folks because of the high performance, low-latency data access it brings to the table, as well as because of its flexibility in handling a variety of data structures. Because it resides in memory, it’s lightening fast, which is always important in modern cloud native architectures.

It’s also widely used. Companies that use Redis Enterprise, the company’s bread-and-butter offering that adds advanced proprietary features, include the cosmetics chain Ultra Beauty, which uses it for real-time inventory management and microservices caching; the office supply chain Staples, which migrated to Redis from a relational database management system some time back; and Freshworks, a software-as-a-service company that uses Redis as a frontend cache, as well as for session management and analytics.

Users can be downright gushy when talking about its versatility and effectiveness at meeting their needs.

“I love the way it scales and handles the concurrent request loads,” one user of Redis Enterprise Cloud identified as Deepak M. wrote on Amazon Web Services’ Marketplace. “This makes our application so fast and it’s a must-have tech stack for all applications.”

Now that Redis is again open source, would you be more likely to choose Redis or Valkey if you needed Redis/Valkey functionality? Redis Valkey It depends on other factors. I don't know. View Results  Loading ...

“We recently planned to rebuild our platform and opted for using this tool for data caching so that the dependency on the MySQL database would be reduced, resulting in fewer server spikes,” another user, Ghoshita N., wrote.

Use of the company’s software is not without downsides, however.

Deepak: “It’s very expensive when we need to handle large data sets in the cache.”

Goshita: “Support is not that helpful if we are stuck.”

Open Source… Then Poof!

Although Redis Enterprise has been a proprietary offering from its first release in 2015, Redis’s core software and its large assortment of client libraries had been open source from its first release in 2009, covered under the BSD-3-Clause license.

That changed in March of 2024 when without warning — and coinciding with the release of Redis 7.4 — the software’s open-source underpinnings disappeared, replaced by a dual-licensing model which gave users the choice to use the Redis Source Available License 2.0, a new variation of a license that Redis had been using for Redis modules since 2019, or the Server Side Public License, which was created in 2018 by MongoDB for its previously open-source NoSQL database.

Neither license is open source, although both have enough open-source similarities to cause open-source advocates to derisively call them “fauxpen source.” The folks at MongoDB tried to get OSI approval for the SSPL when they first started using it, but withdrew it from consideration when it became obvious that they were going to be unsuccessful. Redis acknowledged from the start that RSALv2 isn’t open source.

When announcing the license change on the company’s website, Redis’s CEO Rowan Trollope blamed it on the big public clouds, who he said were “stealing” the companies IP to offer SaaS versions of the software without remunerating Redis. This is a familiar tune, which during the last decade or so has become something of an anthem for open-source database companies.

Examples are many and include not only MongoDB, whose flagship software had long been available under AGPLv3, until it created the SSPL for exactly the same stated reason. In 2019, CockroachDB moved its open-source software — previously licensed under Apache 2 — to the Business Source License, another fauxpen license that was originally written for the folks at MariaDB, another open source database company.

“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,” Trollope wrote. “For example, cloud service providers will be able to deliver Redis 7.4 only after agreeing to licensing terms with Redis.”

Apparently lost in the shuffle were the many volunteer coders who for more than a decade had happily contributed code to an open-source project that was now proprietary… and so was the code they had written.

Does This Make Things Right?

Trollope gives a lot of credit to Salvatore Sanfilippo, the project’s original developer and maintainer, for being the major mover behind the company’s return to open source.

Sanfilippo left Redis in 2020, but returned late last year, nine months or so after Redis’s move to proprietary. Although he supported the company’s move to proprietary in a somewhat rambling personal blog posted early this year, he exhibited a great deal of ambivalence about the move, and was obviously struggling to justify what had been done in his absence.

“If you read the new Redis license, sure it’s not BSD, but basically as long as you don’t sell Redis as a service, you can use it in very similar ways and with similar freedoms as before (what I mean is that you can still modify Redis, redistribute it, use Redis commercially in your for-profit company for free, and so forth),” he wrote. “You can even still sell Redis as a service if you want, as long as you release all the orchestration systems under the same license (something that nobody would likely do, but this shows the copyleft approach of the license). The license language is almost the same as the AGPL, with changes regarding the SaaS stuff. So, not OSI approved? Yes, but I have issues calling the SSPL a closed license.”

In another post that went up late last week at the time of Redis’s change back to open source, Sanfilippo spoke of code he wrote for a new vector set feature that was included in Redis 8, and of his desire to have that code released as open source.

“I truly wanted the code I wrote for the new vector sets data type to be released under an open source license,” he said. “Writing open source software is too rooted in me; I rarely wrote anything else in my career. I’m too old to start now. This may be childish, but I wrote vector sets with a huge amount of enthusiasm exactly because I knew Redis (and my new work) was going to be open source again.”

That enthusiasm notwithstanding, this seems to indicate that Redis’s commitment to openness going forward might be dependent on Sanfilippo remaining with the company and also might be limited to areas in which he willing to make the effort to step up to the plate.

It should be noted as well that Redis’s move away from BSD, its previous open source license, to AGPL might be something of an end run. The successful Redis clone Valkey continues to be licensed under Redis’s original BSD 3-Clause license, which is only one-way compatible with the AGPL. This means that Redis is free to move any improvements or innovations made to Valkey into Redis, while Valkey developers will not be able to move Redis innovations, such as the new vector sets, into Valkey without at least rewriting the code first.

Considering that Valkey is now an official Linux Foundation project, and receives support from a long list of enterprise players that includes Amazon Web Services, Google Cloud, Oracle, Ericsson, Alibaba, Huawei, and Tencent, I think I would be inclined to stick with Valkey and not place my trust in Redis, especially since enterprise-grade features comparable to Redis Enterprise are now available on Valkey-based platforms.

Redis rolled the dice and lost. The future belongs to Valkey.