'''[http://redis.io/%|%Redis]''', by [SS], is an in-memory data structure store.


** Attributes **

&| Website        | http://redis.io |&
&| Repository     | https://github.com/redis/redis |&
&| Latest release | 7.x |&
&| License        | BSD-3-Clause before version 7.4, Redis Source Available License v2 or https://en.wikipedia.org/wiki/Server_Side_Public_License%|%Server Side Public License%|% v1 since. |&
&| Maintainer     | Redis Ltd. |&

[SS] http://antirez.com/news/133%|%stepped down%|% as the maintainer of Redis in June 2020. In March 2024 Redis Ltd. announced it was adopting source-available licenses for Redis, leading to forks.


** Alternatives and forks **

   * https://github.com/valkey-io/valkey%|%Valkey%|% — a fork by former contributors under the original license.
   * https://redict.io%|%Redis%|% — an [LGPL%|%LGPL-3.0-only%|%] fork by Drew DeVault.
   * https://github.com/Snapchat/KeyDB%|%KeyDB%|% — a multithreaded fork under the original license.
   * A https://github.com/stars/dbohdan/lists/resp-databases%|%list of Redis-protocol databases%|% by [dbohdan].


** See Also **

   * [StarStore] — a Redis-like API for [Metakit].


** Description **

Redis is an in-memory data structure store that persists on disk. The data model is key-value, but many different kinds of values are supported: Strings, Lists, Sets, Sorted Sets, Hashes.  It is somewhat like [Memcached], but persistent.

Redis is implemented in C with a test suite written in Tcl. The test suite includes a Tcl https://github.com/antirez/redis/blob/unstable/tests/support/redis.tcl%|%client library%|%.

The first version of Redis, then called "LMDB" (unrelated to [LMDB]), was itself implemented in Tcl. [SS] has published its source code as a https://gist.github.com/antirez/6ca04dd191bdb82aad9fb241013e88a8%|%Gist%|% on [GitHub].


** Tcl clients **

*** Retcl ***

[https://github.com/gahr/retcl%|%Retcl] is an event-driven, object-oriented, Redis client library targeting the Tcl scripting language.

Things that Retcl does which are missing in Salvatore's client are:

   * Pub/Sub support
   * Callbacks specified per subscription pattern / channel
   * Configurable results cache
   * Global and per-command sync / async modes
   * User-defined error handler

*** Other clients ***

There is another client [https://github.com/efrecon/disque/blob/master/resp-0.2.tm%|%library] in the [https://github.com/efrecon/disque%|%disque] client implementation.

https://github.com/bradvoth/redis-tcl%|%redis-tcl%|%: Tcl library for Redis access.



** Redis and Jim Tcl **

Jim Tcl was originally another project of antirez.

Since version 0.81, Jim Tcl can be built with a Redis-client C extension.

You can find a basic Redis client library in pure [Jim Tcl] in [jimhttp]. The library also works in Tcl 8.6 and later.


<<categories>> Caching | Database