Core data types

Redis is a data structure server whose native types cover problems from caching to queuing to event processing. Strings are the most basic type, representing a sequence of bytes. Bitfields efficiently encode multiple counters in a string value, with atomic get, set, and increment operations and different overflow policies; bitmaps perform bitwise operations on strings. Arrays are sparse, index-addressable sequences of strings, and geospatial indexes find locations within a given geographic radius or bounding box. Hashes are record types modeled as collections of field-value pairs, resembling Python dictionaries, Java HashMaps, and Ruby hashes. JSON provides structured, hierarchical arrays and key-value objects matching the JSON text format, while lists, sets, sorted sets, streams, time series, and vector sets round out the general types. Probabilistic types — Bloom filter, Count-min sketch, Cuckoo filter, HyperLogLog, t-digest, and Top-K — compute statistics approximately but efficiently; HyperLogLog estimates the cardinality of large sets. The Compare data types page advises which general-purpose type fits common tasks. Scope: Redis. Reviewed October 4, 2026.