Understand Redis data types
Overview of data types supported by Redis
Redis is a data structure server. At its core, Redis provides a collection of native data types that help you solve a wide variety of problems, from caching to queuing to event processing. Below is a short description of each data type, with links to broader overviews and command references.
If you'd like to try a comprehensive tutorial for each data structure, see their overview pages below.
Core
Strings
Redis strings are the most basic Redis data type, representing a sequence of bytes. For more information, see:
Lists
Redis lists are lists of strings sorted by insertion order. For more information, see:
Sets
Redis sets are unordered collections of unique strings that act like the sets from your favorite programming language (for example, Java HashSets, Python sets, and so on). With a Redis set, you can add, remove, and test for existence in O(1) time (in other words, regardless of the number of set elements). For more information, see:
Hashes
Redis hashes are record types modeled as collections of field-value pairs. As such, Redis hashes resemble Python dictionaries, Java HashMaps, and Ruby hashes. For more information, see:
Sorted sets
Redis sorted sets are collections of unique strings that maintain order by each string's associated score. For more information, see:
Streams
A Redis stream is a data structure that acts like an append-only log. Streams help record events in the order they occur and then syndicate them for processing. For more information, see:
Geospatial indexes
Redis geospatial indexes are useful for finding locations within a given geographic radius or bounding box. For more information, see:
Bitmaps
Redis bitmaps let you perform bitwise operations on strings. For more information, see:
Bitfields
Redis bitfields efficiently encode multiple counters in a string value. Bitfields provide atomic get, set, and increment operations and support different overflow policies. For more information, see:
- Overview of Redis bitfields
- The
BITFIELD
command.
HyperLogLog
The Redis HyperLogLog data structures provide probabilistic estimates of the cardinality (i.e., number of elements) of large sets. For more information, see:
Extensions
To extend the features provided by the included data types, use one of these options:
- Write your own custom server-side functions in Lua.
- Write your own Redis module using the modules API or check out the community-supported modules.
- Use JSON, querying, time series, and other capabilities provided by Redis Stack.