Strings are Redis's most basic value type, and keys identify all data in Redis. Understanding string commands (including atomic counters) and key conventions/management is fundamental to everyday Redis use.
SET name
GET name
SET name EX 60
SETNX lock
MSET a b
APPEND name
STRLEN name
Strings hold text, numbers, or even binary data (up to 512MB). They're versatile — used for cached values, flags, serialized objects, and counters.
SET views 0
INCR views # => 1 (atomic increment)
INCRBY views 10 # => 11
DECR views # decrement
# atomic — safe even with concurrent clients (no race conditions)
Strings holding numbers support atomic increment/decrement — perfect for counters (page views, rate limits, IDs) that are correct even under concurrent access.
# convention: use colon-separated namespaces for organization
SET user:1000:name "Ann" # user 1000's name
SET user:1000:email "[email protected]"
EXISTS user:1000:name # does the key exist? => 1
DEL user:1000:name # delete a key
KEYS user:* # find keys by pattern (⚠️ slow on big DBs — avoid in prod)
SCAN 0 MATCH user:* # iterate keys safely (preferred over KEYS)
TYPE user:1000 # the value's data type
RENAME oldkey newkey # rename
Key naming convention: colon-separated namespaces (user:1000:name) organize keys logically. Important: avoid KEYS in production (it scans all keys, blocking the server) — use SCAN for safe iteration.
Strings and keys are the foundation of everyday Redis use, so understanding them is essential, frequently-applied knowledge. Strings (Redis's most basic and versatile value type) are used constantly — for cached values, flags, serialized data, and especially atomic counters: the atomic INCR/DECR commands make strings perfect for correctly counting things (page views, rate limits, IDs) even under concurrent access, with no race conditions — a valuable, commonly-used capability.
Understanding the string commands (including SET with expiry for TTLs, SETNX for set-if-not-exists which is useful for locks) is everyday practical knowledge. Keys identify all Redis data, and understanding key management is equally important: the naming convention of colon-separated namespaces (user:1000:name) for logically organizing keys is a widely-used best practice that keeps Redis data manageable, and knowing key commands (EXISTS, DEL, TYPE, RENAME) is essential.
A particularly important practical point is avoiding KEYS in production (it scans every key, blocking the single-threaded server — a real performance/availability hazard) in favor of SCAN for safe iteration — a common production pitfall worth knowing.
Since strings and keys are involved in virtually every Redis interaction, and since understanding string commands (especially atomic counters), key naming conventions, and key management (including the KEYS-vs-SCAN production concern) is fundamental to using Redis correctly and safely, understanding strings and keys is essential, must-know knowledge for everyday Redis work, the practical foundation for storing and managing data in Redis.