Connection & Info
redis-cli # Connect (default localhost:6379)
redis-cli -h <host> -p <port> # Connect to specific host/port
redis-cli --tls -u <conn_string> --cacert name.crt # Connect using TLS and CA
PING # Test connection (returns PONG)
INFO # Get server statistics and information
CONFIG GET * # View all configuration parameters
HELLO # Basic server infoKey Operations
KEYS * # List all keys — NEVER in production, O(N) blocks server
SCAN 0 # Iterate through keys safely (cursor-based)
SCAN 0 MATCH user:* COUNT 100 # Filtered cursor iteration
EXISTS <key> # Check if key exists
DEL <key> # Delete a key
TYPE <key> # Get the data type of a key
TTL <key> # Get time to live in seconds
EXPIRE <key> <seconds> # Set expiration time
PERSIST <key> # Remove expiration from key
RENAME <oldkey> <newkey> # Rename a key
MEMORY USAGE <key> # Bytes consumed by keyString Operations
The atomic unit. Max 512 MB per value.
SET <key> <value> # Set a string value
SET <key> <value> EX <seconds> # Set with expiration (replaces SETEX)
SET <key> <value> NX # Set only if not exists (replaces SETNX)
GET <key> # Get a string value
GETSET <key> <value> # Atomic swap — set and return old value
MGET <key1> <key2> ... # Get multiple values
INCR <key> # Increment integer value by 1
DECR <key> # Decrement integer value by 1
INCRBY <key> <increment> # Increment by specific amount
INCRBYFLOAT <key> <increment> # Increment by float
APPEND <key> <value> # Append to string
STRLEN <key> # Get string length
GETRANGE <key> <start> <end> # Get substring
SETRANGE <key> <offset> <value> # Overwrite part of string
# Examples
SET user:1:name "Alice"
SET user:2:data "{\"hello\": \"world\"}"
SET session:user123 "alice" EX 3600
SET user:3:bin "\x63\x69\x61\x6F" # Write in hex format
INCR visits
INCRBY visits 10Hash Operations
The natural fit for structured objects. More memory-efficient than a JSON string when fields are accessed individually.
HSET <key> <field> <value> # Set hash field (also accepts multiple field-value pairs)
HGET <key> <field> # Get hash field value
HMGET <key> <field1> <field2> # Get multiple fields
HGETALL <key> # Get all fields and values
HDEL <key> <field> # Delete hash field
HKEYS <key> # Get all field names
HVALS <key> # Get all values
HLEN <key> # Get number of fields
HEXISTS <key> <field> # Check if field exists
HINCRBY <key> <field> <increment> # Increment hash field
HSCAN <key> <cursor> # Iterate hash fields
# Example
HSET user:1 name "Alice" age 30 role "architect"
HGET user:1 name
HGETALL user:1
HINCRBY user:1 age 1List Operations
Backed by a doubly-linked list (or listpack for small sizes).
LPUSH <key> <value> # Push to list head
RPUSH <key> <value> # Push to list tail
LPOP <key> # Pop from list head
RPOP <key> # Pop from list tail
LRANGE <key> <start> <stop> # Get range (LRANGE key 0 -1 for all)
LLEN <key> # Get list length
LINDEX <key> <index> # Get element by index
LSET <key> <index> <value> # Set element by index
LINSERT <key> BEFORE|AFTER <pivot> <value> # Insert element
LTRIM <key> <start> <stop> # Trim list to range
BLPOP <key> <timeout> # Blocking pop from head
BRPOP <key> <timeout> # Blocking pop from tail
RPOPLPUSH <source> <dest> # Pop from one list, push to another
BRPOPLPUSH <source> <dest> <timeout> # Blocking version
# Example
LPUSH jobs:queue job:3 job:2 job:1
RPUSH jobs:queue job:4
LRANGE jobs:queue 0 -1
BRPOP jobs:queue 30Set Operations
Unordered collection of unique members (hashtable internally).
SADD <key> <member> # Add member to set
SMEMBERS <key> # Get all set members
SISMEMBER <key> <member> # O(1) membership check
SREM <key> <member> # Remove member from set
SCARD <key> # Get set cardinality (size)
SPOP <key> # Remove and return random member
SRANDMEMBER <key> <count> # Get random member(s)
SSCAN <key> <cursor> # Iterate set members
# Set algebra — great for tag intersection, friend-of-friend
SDIFF <key1> <key2> # Set difference
SINTER <key1> <key2> # Set intersection
SUNION <key1> <key2> # Set union
SDIFFSTORE <dest> <key1> <key2> # Store difference result
SINTERSTORE <dest> <key1> <key2> # Store intersection result
SUNIONSTORE <dest> <key1> <key2> # Store union result
# Example
SADD tags:redis post:1 post:3
SADD tags:backend post:2 post:3
SINTER tags:redis tags:backend # {post:3}Sorted Set / ZSET Operations
The killer feature. Members sorted by a float score. O(log N) for most ops.
ZADD <key> <score> <member> # Add member with score
ZRANGE <key> <start> <stop> # Get range by index
ZRANGE <key> 0 -1 WITHSCORES REV # Top to bottom with scores
ZRANGEBYSCORE <key> <min> <max> # Get range by score
ZREVRANGE <key> <start> <stop> # Get range in reverse order
ZREM <key> <member> # Remove member
ZCARD <key> # Get sorted set size
ZCOUNT <key> <min> <max> # Count members in score range
ZINCRBY <key> <increment> <member> # Increment member score
ZRANK <key> <member> # Get member rank (ascending)
ZREVRANK <key> <member> # Get member rank (descending)
ZSCORE <key> <member> # Get member score
ZREMRANGEBYRANK <key> <start> <stop> # Remove by rank range
ZREMRANGEBYSCORE <key> <min> <max> # Remove by score range
ZUNIONSTORE <dest> <numkeys> <key...> # Union of sorted sets
ZINTERSTORE <dest> <numkeys> <key...> # Intersection of sorted sets
ZSCAN <key> <cursor> # Iterate sorted set members
ZPOPMIN <key> <count> # Pop members with lowest scores
ZPOPMAX <key> <count> # Pop members with highest scores
# Use cases: leaderboards, priority queues, time-series indexes, geo
ZADD leaderboard 9500 "alice" 8200 "bob" 7100 "charlie"
ZRANGEBYSCORE leaderboard 8000 +inf
ZINCRBY leaderboard 300 "bob"JSON (RedisJSON)
Nested documents with JSONPath access. Prefer over a serialized String when fields change independently.
JSON.SET <key> $ '<json>' # Set JSON document
JSON.GET <key> # Get full document
JSON.GET <key> $.field # Get specific field (JSONPath)
JSON.SET <key> $.field <value> # Update specific field
JSON.NUMINCRBY <key> $.field <n> # Increment numeric field
JSON.ARRAPPEND <key> $.array <val> # Append to array
JSON.DEL <key> $.field # Delete field
# Example
JSON.SET user:1 $ '{"name":"Alice","age":30,"tags":["redis","architect"]}'
JSON.GET user:1 $.name
JSON.SET user:1 $.age 31
JSON.ARRAPPEND user:1 $.tags '"cache"'Stream Operations
An append-only log with consumer groups — Kafka-lite.
XADD <key> * <field> <value> # Add entry to stream (* = auto ID)
XREAD STREAMS <key> <id> # Read from stream
XRANGE <key> <start> <end> # Get range of entries
XLEN <key> # Get stream length
# Consumer groups
XGROUP CREATE <key> <group> <id> # Create consumer group
XREADGROUP GROUP <group> <consumer> STREAMS <key> > # Read as consumer
XACK <key> <group> <id> # Acknowledge message
XPENDING <key> <group> # Check pending messages
XAUTOCLAIM <key> <group> <consumer> <min-idle> 0 # Reclaim stale messages
# Example
XADD events:orders * order_id 42 amount 199.99 user alice
XGROUP CREATE events:orders shipping $ MKSTREAM
XREADGROUP GROUP shipping worker1 COUNT 5 STREAMS events:orders >
XACK events:orders shipping <message-id>Pub/Sub (Messaging)
Fire-and-forget broadcast — no persistence, no consumer groups.
PUBLISH <channel> <message> # Send message to channel
SUBSCRIBE <channel> # Subscribe to channel(s)
PSUBSCRIBE <pattern> # Subscribe using pattern matching
UNSUBSCRIBE <channel> # Unsubscribe from channel
PUBSUB CHANNELS # List active channels
PUBSUB NUMSUB <channel> # Get subscriber count for channels
# Example
# Terminal 1 - subscriber
SUBSCRIBE channel:notifications
# Terminal 2 - publisher
PUBLISH channel:notifications '{"event":"order_paid","id":42}'
# Pattern subscribe
PSUBSCRIBE channel:*Transactions
MULTI # Start transaction block
EXEC # Execute all commands in transaction
DISCARD # Cancel transaction
WATCH <key> # Watch key for optimistic locking (CAS)
UNWATCH # Clear all watched keysLua Scripting
Scripts run atomically on the server — no other commands execute in between. Use for read-modify-write sequences without transaction overhead.
EVAL <script> <numkeys> <key...> <arg...> # Execute Lua script
EVALSHA <sha1> <numkeys> <key...> <arg...> # Execute cached script
SCRIPT LOAD <script> # Load script into cache
SCRIPT EXISTS <sha1> # Check if script is cached
SCRIPT FLUSH # Remove all cached scripts
SCRIPT KILL # Kill running scriptTypeScript example — rate limiter:
import { createClient } from 'redis'
const redis = createClient()
await redis.connect()
// KEYS[1] = rate limit key, ARGV[1] = limit, ARGV[2] = window TTL in seconds
const rateLimiter = `
local current = redis.call('INCR', KEYS[1])
if current == 1 then
redis.call('EXPIRE', KEYS[1], ARGV[2])
end
return current
`
const key = 'ratelimit:user:42'
// In production: use SCRIPT LOAD + EVALSHA (or the client's built-in method) instead of EVAL
const count = await redis.eval(rateLimiter, { keys: [key], arguments: ['10', '60'] })
console.log(count <= 10 ? 'allowed' : 'rate limited')Bit Operations (Bitmaps)
SETBIT <key> <offset> <value> # Set bit at offset
GETBIT <key> <offset> # Get bit at offset
BITCOUNT <key> # Count set bits
BITOP AND|OR|XOR|NOT <destkey> <key...> # Bitwise operations
BITPOS <key> <bit> # Find first bit set/clearHyperLogLog (Cardinality Estimation)
Approximate unique count, fixed 12 KB, < 1% error.
PFADD <key> <element...> # Add elements
PFCOUNT <key...> # Get approximate count
PFMERGE <destkey> <sourcekey...> # Merge HyperLogLogs
# Example
PFADD page:views:2024-01-01 user:1 user:2 user:3 user:1 # duplicates ignored
PFCOUNT page:views:2024-01-01 # ≈ 3
PFMERGE page:views:week page:views:2024-01-01 page:views:2024-01-02Probabilistic (Bloom Filter)
Built-in from Redis 8 via RedisBloom. Set membership with no false negatives.
BF.ADD <key> <item> # Add item to Bloom filter
BF.EXISTS <key> <item> # Check membership (may false-positive; never false-negative)
BF.MADD <key> <item...> # Add multiple items
# Example
BF.ADD blocklist "spam@example.com"
BF.EXISTS blocklist "spam@example.com" # 1
BF.MADD blocklist "a@b.com" "c@d.com"Geospatial
Coordinates encoded into a Sorted Set score. O(log N) radius queries.
GEOADD <key> <long> <lat> <member> # Add location
GEODIST <key> <member1> <member2> <unit> # Get distance
GEOPOS <key> <member> # Get coordinates
GEOHASH <key> <member> # Get geohash string
GEOSEARCH <key> FROMLONLAT <long> <lat> BYRADIUS <radius> <unit> # Query from coordinates
GEOSEARCH <key> FROMMEMBER <member> BYRADIUS <radius> <unit> # Query from member
# Example
GEOADD locations 13.361389 38.115556 "Palermo" 15.087269 37.502669 "Catania"
GEODIST locations Palermo Catania km
GEOSEARCH locations FROMLONLAT 15 37 BYRADIUS 200 km ASC COUNT 5 WITHCOORD WITHDISTTime Series (RedisTimeSeries)
Append-only timestamped metrics with built-in downsampling and aggregation.
TS.CREATE <key> RETENTION <ms> LABELS <label> <value> # Create time series
TS.ADD <key> * <value> # Add entry (* = auto timestamp)
TS.RANGE <key> <from> <to> COUNT <n> # Query range
TS.MGET FILTER <label>=<value> # Multi-key label query
TS.CREATERULE <src> <dest> AGGREGATION <func> <bucket> # Downsampling rule
# Example
TS.CREATE cpu:host1 RETENTION 86400000 LABELS host host1 metric cpu
TS.ADD cpu:host1 * 72.5
TS.RANGE cpu:host1 - + COUNT 10
TS.CREATERULE cpu:host1 cpu:host1:5m AGGREGATION avg 300000Vector Sets
Fixed-dimension float vectors for approximate nearest-neighbor search. Powers semantic search and RAG pipelines.
VADD <key> VALUES <dim> <v1> <v2> ... <member> # Add vector
VSIM <key> VALUES <dim> <v1> <v2> ... COUNT <n> # k-nearest neighbors
VCARD <key> # Count vectors
VREM <key> <member> # Remove vector
# Example
VADD doc:embeddings VALUES 3 1.0 0.2 0.8 "doc:1"
VADD doc:embeddings VALUES 3 0.9 0.3 0.7 "doc:2"
VSIM doc:embeddings VALUES 3 1.0 0.1 0.9 COUNT 3Database & Admin
SELECT <db> # Switch to database number (0–15 by default)
FLUSHDB # Clear current database
FLUSHALL # Clear all databases
DBSIZE # Get number of keys in current database
MONITOR # Watch all commands in real-time (debug only)
SAVE # Synchronous save to disk
BGSAVE # Background save to disk
MOVE <key> <db> # Atomically move key to another databaseMemory & Performance
MEMORY USAGE <key> # Get memory used by key
MEMORY STATS # Memory allocation stats
MEMORY DOCTOR # Memory usage report
SLOWLOG GET <count> # Get slow queries
SLOWLOG LEN # Get slow log length
SLOWLOG RESET # Clear slow logConnection Management
CLIENT LIST # List connected clients
CLIENT KILL <ip:port> # Kill client connection
CLIENT SETNAME <name> # Set client name
CLIENT GETNAME # Get client nameDebug & Introspection
TYPE <key> # Get data type
OBJECT ENCODING <key> # Get internal encoding (listpack vs hashtable)
OBJECT REFCOUNT <key> # Get reference count
OBJECT IDLETIME <key> # Get idle time in seconds
DEBUG OBJECT <key> # Get debug info about key
DUMP <key> # Serialize key value
RESTORE <key> <ttl> <data> # Restore serialized valueCluster Commands
CLUSTER INFO # Get cluster information
CLUSTER NODES # List all nodes
CLUSTER SLOTS # Get slot assignments
CLUSTER KEYSLOT <key> # Get hash slot for key
# CLI cluster management
redis-cli --cluster create host1:6379 host2:6379 ... --cluster-replicas 1
redis-cli --cluster rebalance host1:6379
redis-cli --cluster reshard host1:6379CLI Options & Modes
redis-cli --scan --pattern "user:*" # Search for keys by pattern
redis-cli --bigkeys # Find biggest keys
redis-cli --stat # Show continuous stats
redis-cli --latency # Measure latency
redis-cli --latency-history # Latency history
redis-cli --intrinsic-latency <seconds> # Measure system latency
redis-cli --rdb <filename> # Download RDB backup
redis-cli --pipe # Pipe mode for mass insertion
redis-cli --csv # Output in CSV format
redis-cli --ldb # Start Lua debugger
redis-cli --eval <file> <keys> , <args> # Execute Lua script from file