Redis

Redis (Remote Dictionary Server) is an in-memory data store used as a database, cache, and message broker. It supports strings, hashes, lists, sets, sorted sets, bitmaps, and more.

Overview

Redis is known for its exceptional performance, as data resides in memory. It supports persistence via RDB snapshots and AOF (Append Only File) logs. Redis also provides clustering for horizontal scaling and Sentinel for high availability.

Key Features

  • In-memory data storage with sub-millisecond latency
  • Rich data structures: strings, lists, sets, hashes, streams
  • Pub/Sub messaging and streams for event-driven architectures
  • Replication and Redis Cluster for horizontal scaling
  • Redis Sentinel for high availability
  • Redis Modules for extending functionality (search, graph, AI)

Licensing

Redis uses a tri-license model as of version 8.0:

  • Redis Open Source (AGPL v3): The core Redis code is available under the GNU Affero General Public License, making it freely usable and modifiable.
  • Redis Source Available (RSALv2): For cloud and enterprise features that cannot be used under AGPL.
  • Redis Commercial: Enterprise-grade commercial license.

Redis Community Edition (formerly Redis Open Source) remains free and open source.

See Redis Licensing for details.

Official Resources