Introduction to Redis

• 1: Who's using Redis?
• 2: Redis open source governance
• 3: Redis release cycle
• 4: Redis sponsors
• 5: Redis license
• 6: Redis trademark guidelines

1 - Who's using Redis?

A list of well known companies using Redis:

• Twitter
• GitHub
• Snapchat
• Craigslist
• StackOverflow

And many others! techstacks.io maintains a list of popular sites using Redis.

2 - Redis open source governance

From 2009-2020, Salvatore Sanfilippo built, led, and maintained the Redis open source project. During this time, Redis had no formal governance structure, operating primarily as a BDFL-style project.

As Redis grew, matured, and expanded its user base, it became increasingly important to form a sustainable structure for its ongoing development and maintenance. Salvatore and the core Redis contributors wanted to ensure the project’s continuity and reflect its larger community. With this in mind, a new governance structure was adopted.

Current governance structure

Starting on June 30, 2020, Redis adopted a light governance model that matches the current size of the project and minimizes the changes from its earlier model. The governance model is intended to be a meritocracy, aiming to empower individuals who demonstrate a long-term commitment and make significant contributions.

The Redis core team

Salvatore Sanfilippo named two successors to take over and lead the Redis project: Yossi Gottlieb (yossigo) and Oran Agra (oranagra)

With the backing and blessing of Redis Ltd., we took this opportunity to create a more open, scalable, and community-driven “core team” structure to run the project. The core team consists of members selected based on demonstrated, long-term personal involvement and contributions.

The current core team members are:

• Project Lead: Yossi Gottlieb (yossigo) from Redis Ltd.
• Project Lead: Oran Agra (oranagra) from Redis Ltd.
• Community Lead: Itamar Haber (itamarhaber) from Redis Ltd.
• Member: Zhao Zhao (soloestoy) from Alibaba
• Member: Madelyn Olson (madolson) from Amazon Web Services

The Redis core team members serve the Redis open source project and community. They are expected to set a good example of behavior, culture, and tone in accordance with the adopted Code of Conduct. They should also consider and act upon the best interests of the project and the community in a way that is free from foreign or conflicting interests.

The core team will be responsible for the Redis core project, which is the part of Redis that is hosted in the main Redis repository and is BSD licensed. It will also aim to maintain coordination and collaboration with other projects that make up the Redis ecosystem, including Redis clients, satellite projects, major middleware that relies on Redis, etc.

Roles and responsibilities

The core team has the following remit:

• Managing the core Redis code and documentation
• Managing new Redis releases
• Maintaining a high-level technical direction/roadmap
• Providing a fast response, including fixes/patches, to address security vulnerabilities and other major issues
• Project governance decisions and changes
• Coordination of Redis core with the rest of the Redis ecosystem
• Managing the membership of the core team

The core team aims to form and empower a community of contributors by further delegating tasks to individuals who demonstrate commitment, know-how, and skills. In particular, we hope to see greater community involvement in the following areas:

• Support, troubleshooting, and bug fixes of reported issues
• Triage of contributions/pull requests

Decision making

• Normal decisions will be made by core team members based on a lazy consensus approach: each member may vote +1 (positive) or -1 (negative). A negative vote must include thorough reasoning and better yet, an alternative proposal. The core team will always attempt to reach a full consensus rather than a majority. Examples of normal decisions:
  • Day-to-day approval of pull requests and closing issues
  • Opening new issues for discussion
• Major decisions that have a significant impact on the Redis architecture, design, or philosophy as well as core-team structure or membership changes should preferably be determined by full consensus. If the team is not able to achieve a full consensus, a majority vote is required. Examples of major decisions:
  • Fundamental changes to the Redis core
  • Adding a new data structure
  • Creating a new version of RESP (Redis Serialization Protocol)
  • Changes that affect backward compatibility
  • Adding or changing core team members
• Project leads have a right to veto major decisions

Core team membership

• The core team is not expected to serve for life, however, long-term participation is desired to provide stability and consistency in the Redis programming style and the community.
• If a core-team member whose work is funded by Redis Ltd. must be replaced, the replacement will be designated by Redis Ltd. after consultation with the remaining core-team members.
• If a core-team member not funded by Redis Ltd. will no longer participate, for whatever reason, the other team members will select a replacement.

Community forums and communications

We want the Redis community to be as welcoming and inclusive as possible. To that end, we have adopted a Code of Conduct that we ask all community members to read and observe.

We encourage that all significant communications will be public, asynchronous, archived, and open for the community to actively participate in using the channels described here. The exception to that is sensitive security issues that require resolution prior to public disclosure.

To contact the core team about sensitive matters, such as misconduct or security issues, please email redis@redis.io.

New Redis repository and commits approval process

The Redis core source repository is hosted under https://github.com/redis/redis. Our target is to eventually host everything (the Redis core source and other ecosystem projects) under the Redis GitHub organization (https://github.com/redis). Commits to the Redis source repository will require code review, approval of at least one core-team member who is not the author of the commit, and no objections.

Project and development updates

Stay connected to the project and the community! For project and community updates, follow the project channels. Development announcements will be made via the Redis mailing list.

Updates to these governance rules

Any substantial changes to these rules will be treated as a major decision. Minor changes or ministerial corrections will be treated as normal decisions.

3 - Redis release cycle

Redis is system software and a type of system software that holds user data, so it is among the most critical pieces of a software stack.

For this reason, Redis' release cycle is such that it ensures highly-stable releases, even at the cost of slower cycles.

New releases are published in the Redis GitHub repository and are also available for download. Announcements are sent to the Redis mailing list and by @redisfeed on Twitter.

Release cycle

A given version of Redis can be at three different levels of stability:

• Unstable
• Release Candidate
• Stable

Unstable tree

The unstable version of Redis is located in the unstable branch in the Redis GitHub repository.

This branch is the source tree where most of the new features are under development. unstable is not considered production-ready: it may contain critical bugs, incomplete features, and is potentially unstable.

However, we try hard to make sure that even the unstable branch is usable most of the time in a development environment without significant issues.

Release candidate

New minor and major versions of Redis begin as forks of the unstable branch. The forked branch's name is the target release

For example, when Redis 6.0 was released as a release candidate, the unstable branch was forked into the 6.0 branch. The new branch is the release candidate (RC) for that version.

Bug fixes and new features that can be stabilized during the release's time frame are committed to the unstable branch and backported to the release candidate branch. The unstable branch may include additional work that is not a part of the release candidate and scheduled for future releases.

The first release candidate, or RC1, is released once it can be used for development purposes and for testing the new version. At this stage, most of the new features and changes the new version brings are ready for review, and the release's purpose is collecting the public's feedback.

Subsequent release candidates are released every three weeks or so, primarily for fixing bugs. These may also add new features and introduce changes, but at a decreasing rate and decreasing potential risk towards the final release candidate.

Stable tree

Once development has ended and the frequency of critical bug reports for the release candidate wanes, it is ready for the final release. At this point, the release is marked as stable and is released with "0" as its patch-level version.

Versioning

Stable releases liberally follow the usual major.minor.patch semantic versioning schema. The primary goal is to provide explicit guarantees regarding backward compatibility.

Patch-Level versions

Patches primarily consist of bug fixes and very rarely introduce any compatibility issues.

Upgrading from a previous patch-level version is almost always safe and seamless.

New features and configuration directives may be added, or default values changed, as long as these don’t carry significant impacts or introduce operations-related issues.

Minor versions

Minor versions usually deliver maturity and extended functionality.

Upgrading between minor versions does not introduce any application-level compatibility issues.

Minor releases may include new commands and data types that introduce operations-related incompatibilities, including changes in data persistence format and replication protocol.

Major versions

Major versions introduce new capabilities and significant changes.

Ideally, these don't introduce application-level compatibility issues.

Release schedule

A new major version is planned for release once a year.

Generally, every major release is followed by a minor version after six months.

Patches are released as needed to fix high-urgency issues, or once a stable version accumulates enough fixes to justify it.

For contacting the core team on sensitive matters and security issues, please email redis@redis.io.

Support

As a rule, older versions are not supported as we try very hard to make the Redis API mostly backward compatible.

Upgrading to newer versions is the recommended approach and is usually trivial.

The latest stable release is always fully supported and maintained.

Two additional versions receive maintenance only, meaning that only fixes for critical bugs and major security issues are committed and released as patches:

• The previous minor version of the latest stable release.
• The previous stable major release.

For example, consider the following hypothetical versions: 1.2, 2.0, 2.2, 3.0, 3.2.

When version 2.2 is the latest stable release, both 2.0 and 1.2 are maintained.

Once version 3.0.0 replaces 2.2 as the latest stable, versions 2.0 and 2.2 are maintained, whereas version 1.x reaches its end of life.

This process repeats with version 3.2.0, after which only versions 2.2 and 3.0 are maintained.

The above are guidelines rather than rules set in stone and will not replace common sense.

4 - Redis sponsors

From 2015 to 2020, Salvatore Sanfilippo's work on Redis was sponsored by Redis Ltd. Since June 2020, Redis Ltd. has sponsored the governance of Redis. Redis Ltd. also sponsors the hosting and maintenance of redis.io.

Past sponsorships:

• The Shuttleworth Foundation has donated 5000 USD to the Redis project in form of a flash grant.
• From May 2013 to June 2015, the work Salvatore Sanfilippo did to develop Redis was sponsored by Pivotal.
• Before May 2013, the project was sponsored by VMware with the work of Salvatore Sanfilippo and Pieter Noordhuis.
• VMware and later Pivotal provided a 24 GB RAM workstation for Salvatore to run the Redis CI test and other long running tests. Later, Salvatore equipped the server with an SSD drive in order to test in the same hardware with rotating and flash drives.
• Linode, in January 2010, provided virtual machines for Redis testing in a virtualized environment.
• Slicehost, January 2010, provided Virtual Machines for Redis testing in a virtualized environment.
• Citrusbyte, in December 2009, contributed part of Virtual Memory implementation.
• Hitmeister, in December 2009, contributed part of Redis Cluster.
• Engine Yard, in December 2009, contributed blocking POP (BLPOP) and part of the Virtual Memory implementation.

Also thanks to the following people or organizations that donated to the Project:

• Emil Vladev
• Brad Jasper
• Mrkris

The Redis community is grateful to Redis Ltd., Pivotal, VMware and to the other companies and people who have donated to the Redis project. Thank you.

redis.io

Citrusbyte sponsored the creation of the official Redis logo (designed by Carlos Prioglio) and transferred its copyright to Salvatore Sanfilippo.

They also sponsored the initial implementation of this site by Damian Janowski and Michel Martens.

The redis.io domain was donated for a few years to the project by I Want My Name.

5 - Redis license

Redis is open source software released under the terms of the three clause BSD license. Most of the Redis source code was written and is copyrighted by Salvatore Sanfilippo and Pieter Noordhuis. A list of other contributors can be found in the git history.

The Redis trademark and logo are owned by Redis Ltd. and can be used in accordance with the Redis Trademark Guidelines.

Three clause BSD license

Every file in the Redis distribution, with the exceptions of third party files specified in the list below, contain the following license:

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

• Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

• Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

• Neither the name of Redis nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Third-party files and licenses

Redis uses source code from third parties. All this code contains a BSD or BSD-compatible license. The following is a list of third-party files and information about their copyright.

• Redis uses the LHF compression library. LibLZF is copyright Marc Alexander Lehmann and is released under the terms of the two-clause BSD license.

• Redis uses the sha1.c file that is copyright by Steve Reid and released under the public domain. This file is extremely popular and used among open source and proprietary code.

• When compiled on Linux Redis uses the Jemalloc allocator, that is copyright by Jason Evans, Mozilla Foundation and Facebook, Inc and is released under the two-clause BSD license.

• Inside Jemalloc the file pprof is copyright Google Inc and released under the three-clause BSD license.

• Inside Jemalloc the files inttypes.h, stdbool.h, stdint.h, strings.h under the msvc_compat directory are copyright Alexander Chemeris and released under the three-clause BSD license.

• The libraries hiredis and linenoise also included inside the Redis distribution are copyright Salvatore Sanfilippo and Pieter Noordhuis and released under the terms respectively of the three-clause BSD license and two-clause BSD license.

6 - Redis trademark guidelines

1. OPEN SOURCE LICENSE VS. TRADEMARKS. The three-clause BSD license gives you the right to redistribute and use the software in source and binary forms, with or without modification, under certain conditions. However, open source licenses like the three-clause BSD license do not address trademarks. Redis trademarks and brands need to be used in a way consistent with trademark law, and that is why we have prepared this policy – to help you understand what branding is allowed or required when using our software.

2. PURPOSE. To outline the policy and guidelines for using the Redis trademark (“Mark”) and logo (“Logo”).

3. WHY IS THIS IMPORTANT? The Mark and Logo are symbols of the quality and community support associated with the open source Redis. Trademarks protect not only its owners, but its users and the entire open source community. Our community members need to know that they can rely on the quality represented by the brand. No one should use the Mark or Logo in any way that misleads anyone, either directly or by omission, or in any way that is likely to confuse or take advantage of the community, or constitutes unfair competition. For example, you cannot say you are distributing Redis software when you are distributing a modified version of Redis open source, because people will be confused when they are not getting the same features and functionality they would get if they downloaded the software directly from Redis, or will think that the modified software is endorsed or sponsored by us or the community. You also cannot use the Mark or Logo on your website or in connection with any services in a way that suggests that your website is an official Redis website or service, or that suggests that we endorse your website or services.

4. PROPER USE OF THE REDIS TRADEMARKS AND LOGO. You may do any of the following:

   • a. When you use an unaltered, unmodified copy of open source Redis downloaded from https://redis.io (the “Software”) as a data source for your application, you may use the Mark and Logo to identify your use. The open source Redis software combined with, or integrated into, any other software program, including but not limited to automation software for offering Redis as a cloud service or orchestration software for offering Redis in containers is considered “modified” Redis software and does not entitle you to use the Mark or the Logo, except in a case of nominative use, as described below. Integrating the Software with other software or service can introduce performance or quality control problems that can devalue the goodwill in the Redis brand and we want to be sure that such problems do not confuse users as to the quality of the product.
   • b. The Software is developed by and for the Redis community. If you are engaged in community advocacy, you can use the Mark but not the Logo in the context of showing support for the open source Redis project, provided that:
     • i. The Mark is used in a manner consistent with this policy;
     • ii. There is no commercial purpose behind the use and you are not offering Redis commercially under the same domain name;
     • iii. There is no suggestion that you are the creator or source of Redis, or that your project is approved, sponsored, or affiliated with us or the community; and
     • iv. You must include attribution according to section 6.a. below.
   • c. Nominative Use: Trademark law permits third parties the use of a mark to identify the trademark holder’s product or service so long as such use is not likely to cause unnecessary consumer or public confusion. This is referred to as a nominative or fair use. When you distribute, or offer an altered, modified or combined copy of the Software, such as in the case of a cloud service or a container service, you may engage in “nominative use” of the Mark, but this does not allow you to use the Logo.
   • d. Examples of Nominative Use:
     • i. Offering an XYZ software, which is an altered, modified or combined copy of the open source Redis software, including but not limited to offering Redis as a cloud service or as a container service, and while fully complying with the open source Redis API - you may only name it "XYZ for Redis®" or state that "XYZ software is compatible with the Redis® API". No other term or description of your software is allowed.
     • ii. Offering an ABC application, which uses an altered, modified or combined copy of the open source Redis software as a data source, including but not limited to using Redis as a cloud service or a container service, and while the modified Redis fully complies with the open source Redis API - you may only state that "ABC application is using XYZ for Redis®", or "ABC application is using a software which is compatible with the Redis® API". No other term or description of your application is allowed.
     • iii. If, however, the offered XYZ software, or service based thereof, or application ABC uses an altered, modified or combined copy of the open source Redis software that does not fully comply with the open source Redis API - you may not use the Mark and Logo at all.
   • e. In any use (or nominative use) of the Mark or the Logo as per the above, you should comply with all the provisions of Section 6 (General Use).

5. IMPROPER USE OF THE REDIS TRADEMARKS AND LOGOS. Any use of the Mark or Logo other than as expressly described as permitted herein is not permitted because we believe that it would likely cause impermissible public confusion. Use of the Mark that we will likely consider infringing without permission for use include:

   • a. Entity Names. You may not form a company, use a company name, or create a software product or service name that includes the Mark or implies any that such company is the source or sponsor of Redis. If you wish to form an entity for a user or developer group, please contact us and we will be glad to discuss a license for a suitable name;
   • b. Class or Quality. You may not imply that you are providing a class or quality of Redis (e.g., "enterprise-class" or "commercial quality" or “fully managed”) in a way that implies Redis is not of that class, grade or quality, nor that other parties are not of that class, grade, or quality;
   • c. False or Misleading Statements. You may not make false or misleading statements regarding your use of Redis (e.g., "we wrote the majority of the code" or "we are major contributors" or "we are committers");
   • d. Domain Names and Subdomains. You must not use Redis or any confusingly similar phrase in a domain name or subdomain. For instance “www.Redishost.com” is not allowed. If you wish to use such a domain name for a user or developer group, please contact us and we will be glad to discuss a license for a suitable domain name. Because of the many persons who, unfortunately, seek to spoof, swindle or deceive the community by using confusing domain names, we must be very strict about this rule;
   • e. Websites. You must not use our Mark or Logo on your website in a way that suggests that your website is an official website or that we endorse your website;
   • f. Merchandise. You must not manufacture, sell or give away merchandise items, such as T-shirts and mugs, bearing the Mark or Logo, or create any mascot for Redis. If you wish to use the Mark or Logo for a user or developer group, please contact us and we will be glad to discuss a license to do this;
   • g. Variations, takeoffs or abbreviations. You may not use a variation of the Mark for any purpose. For example, the following are not acceptable:
     • i. Red;
     • ii. MyRedis; and
     • iii. RedisHost.
   • h. Rebranding. You may not change the Mark or Logo on a redistributed (unmodified) Software to your own brand or logo. You may not hold yourself out as the source of the Redis software, except to the extent you have modified it as allowed under the three-clause BSD license, and you make it clear that you are the source only of the modification;
   • i. Combination Marks. Do not use our Mark or Logo in combination with any other marks or logos. For example Foobar Redis, or the name of your company or product typeset to look like the Redis logo; and
   • j. Web Tags. Do not use the Mark in a title or metatag of a web page to influence search engine rankings or result listings, rather than for discussion or advocacy of the Redis project.

6. GENERAL USE INFORMATION.

   • a. Attribution. Any permitted use of the Mark or Logo, as indicated above, should comply with the following provisions:
     • i. You should add the R mark (®) and an asterisk (*) to the first mention of the word "Redis" as part of or in connection with a product name;
     • ii. Whenever "Redis®*" is shown - add the following legend (with an asterisk) in a noticeable and readable format: "* Redis is a trademark of Redis Ltd. Any rights therein are reserved to Redis Ltd. Any use by <company XYZ> is for referential purposes only and does not indicate any sponsorship, endorsement or affiliation between Redis and <company XYZ>"; and
     • iii. Sections i. and ii. above apply to any appearance of the word "Redis" in: (a) any web page, gated or un-gated; (b) any marketing collateral, white paper, or other promotional material, whether printed or electronic; and (c) any advertisement, in any format.
   • b. Capitalization. Always distinguish the Mark from surrounding text with at least initial capital letters or in all capital letters, (e.g., as Redis or REDIS).
   • c. Adjective. Always use the Mark as an adjective modifying a noun, such as “the Redis software.”
   • d. Do not make any changes to the Logo. This means you may not add decorative elements, change the colors, change the proportions, distort it, add elements or combine it with other logos.

7. NOTIFY US OF ABUSE. Do not make any changes to the Logo. This means you may not add decorative elements, change the colors, change the proportions, distort it, add elements or combine it with other logos.

8. MORE QUESTIONS? If you have questions about this policy, or wish to request a license for any uses that are not specifically authorized in this policy, please contact us at legal@redis.com.