$devvkit resources --cheatsheet redis-cheatsheet

Redis Cheatsheet

[databases]

Every essential Redis command: strings, hashes, lists, sets, sorted sets, expiration, pub/sub, and transactions, with syntax and real use cases.99 commands · 7 sections

Redis is an in-memory data store used for caching, queues, sessions, and leaderboards. This cheatsheet covers the commands you use daily: strings and counters, hashes, lists as queues, sets and sorted sets, key expiration, pub/sub, and transactions.

Every command shows its syntax with placeholders followed by the use case.

Strings17

$SET key value

Use case: Store a string value.Example: SET user:1:name "Jane"

$GET key

Use case: Read a string value.Example: GET user:1:name

$SET key value EX 60

Use case: Set with expiration: cache entries that auto-expire.Example: SET page:home "<html>" EX 300

$SET key value NX

Use case: Set only if the key does NOT exist: locks and dedup.Example: SET lock:job 1 NX EX 30

$SET key value XX

Use case: Set only if the key already exists: update-only.Example: SET counter:today 5 XX

$SETEX key 60 value

Use case: Set with expiration in one command.Example: SETEX otp:user:5 120 "123456"

$INCR key

Use case: Increment a counter: page views, API usage.Example: INCR stats:visits

$INCRBY key 10

Use case: Increment by a specific amount.Example: INCRBY user:5:score 10

$DECR key / DECRBY key 5

Use case: Decrement a counter: inventory, tokens.Example: DECR stock:sku-42

$SETNX key value

Use case: Set-if-not-exists: the distributed lock primitive.Example: SETNX lock:deploy 1

$GETSET key newvalue

Use case: Get the old value AND set a new one atomically.Example: GETSET last:seen "2026-08-17"

$MGET k1 k2 k3

Use case: Read multiple keys in one round-trip.Example: MGET user:1:name user:2:name

$MSET k1 v1 k2 v2

Use case: Write multiple keys atomically.Example: MSET user:1:name "Jane" user:1:plan "pro"

$APPEND key value

Use case: Append to a string value: log builders.Example: APPEND log:errors "line1 "

$STRLEN key

Use case: Length of a string value.Example: STRLEN otp:user:5

$GETRANGE key start end

Use case: Substring of a value.Example: GETRANGE token 0 9

$GETEX key EX 60

Use case: Get a value and set its expiration in one call: touch pattern.Example: GETEX session:42 EX 900

Hashes11

$HSET key field value

Use case: Set one field of a hash: user profiles.Example: HSET user:5 name "Jane" plan "pro"

$HGET key field

Use case: Read one field.Example: HGET user:5 plan

$HGETALL key

Use case: Read ALL fields: the full object.Example: HGETALL user:5

$HMGET key f1 f2

Use case: Read multiple fields in one call.Example: HMGET user:5 name email

$HINCRBY key field 1

Use case: Increment a numeric field inside a hash.Example: HINCRBY user:5 login_count 1

$HDEL key field

Use case: Delete a field from a hash.Example: HDEL user:5 temp_field

$HEXISTS key field

Use case: Check if a field exists.Example: HEXISTS user:5 email

$HLEN key

Use case: Number of fields.Example: HLEN user:5

$HKEYS key

Use case: List all field names.Example: HKEYS user:5

$HSETNX key field value

Use case: Set a field only if it does not exist.Example: HSETNX user:5 referrer "google"

$HSCAN key 0 MATCH user:* COUNT 100

Use case: Incrementally scan hash fields: no blocking HGETALL on huge hashes.Example: HSCAN user:5 0

Lists15

$LPUSH key value

Use case: Push to the LEFT (head): newest-first lists.Example: LPUSH notifications:5 "New message"

$RPUSH key value

Use case: Push to the RIGHT (tail): queue enqueue.Example: RPUSH jobs:queue "job-123"

$LPOP key

Use case: Pop from the LEFT: queue dequeue (FIFO).Example: LPOP jobs:queue

$RPOP key

Use case: Pop from the RIGHT: LIFO stack.Example: RPOP undo:stack

$BLPOP key 5

Use case: Blocking pop with timeout: wait for work instead of polling.Example: BLPOP jobs:queue 5

$BRPOP key 5

Use case: Blocking right pop: priority processing.Example: BRPOP tasks:queue 5

$LRANGE key 0 -1

Use case: Read the whole list.Example: LRANGE notifications:5 0 -1

$LRANGE key 0 9

Use case: First 10 items: pagination.Example: LRANGE timeline:5 0 9

$LLEN key

Use case: List length: queue depth.Example: LLEN jobs:queue

$LTRIM key 0 99

Use case: Keep only the first 100: cap logs and history.Example: RPUSH logs "line"; LTRIM logs -100 -1

$LINDEX key index

Use case: Read an item by index.Example: LINDEX undo:stack 0

$LSET key index value

Use case: Overwrite an item by index.Example: LSET jobs:queue 0 "rerun"

$LREM key count value

Use case: Remove occurrences of a value.Example: LREM queue 1 "job-42"

$LPUSHX / RPUSHX key value

Use case: Push only if the list exists: avoid recreating deleted lists.Example: RPUSHX jobs:queue "job-1"

$RPOPLPUSH source dest

Use case: Pop from one list, push to another: processing + retry queue pattern.Example: RPOPLPUSH jobs:queue processing:queue

Sets & Sorted Sets20

$SADD key member

Use case: Add a member to a set: deduplicated membership.Example: SADD online:users "user-1"

$SMEMBERS key

Use case: List all members.Example: SMEMBERS tags:post:42

$SISMEMBER key member

Use case: Membership check: is this user online?Example: SISMEMBER online:users "user-1"

$SREM key member

Use case: Remove a member.Example: SREM online:users "user-1"

$SCARD key

Use case: Set size: online count.Example: SCARD online:users

$SINTER k1 k2

Use case: Intersection: mutual followers, common tags.Example: SINTER followers:1 followers:2

$SUNION k1 k2

Use case: Union: merge audiences.Example: SUNION list:a list:b

$SDIFF k1 k2

Use case: Difference: in k1 but not k2.Example: SDIFF all:users active:users

$SISMEMBER key member

Use case: O(1) membership: the reason sets beat lists for checks.Example: SISMEMBER banned:ips "1.2.3.4"

$SADD key member EX 3600

Use case: Set member with TTL (Redis 7.4+): temporary membership.Example: SADD promo:codes "SAVE10" EX 86400

$ZADD key score member

Use case: Add a member with a score: leaderboards.Example: ZADD leaderboard 1500 "player-1"

$ZINCRBY key 10 member

Use case: Increase a member's score: winner moves up.Example: ZINCRBY leaderboard 10 "player-1"

$ZRANGE key 0 -1 WITHSCORES

Use case: List members ordered by score.Example: ZRANGE leaderboard 0 -1 WITHSCORES

$ZREVRANGE key 0 9 WITHSCORES

Use case: Top 10: reverse order by score.Example: ZREVRANGE leaderboard 0 9 WITHSCORES

$ZRANK key member

Use case: A member's position (lowest score = 0).Example: ZRANK leaderboard "player-1"

$ZSCORE key member

Use case: A member's score.Example: ZSCORE leaderboard "player-1"

$ZREM key member

Use case: Remove a member.Example: ZREM leaderboard "player-1"

$ZCARD key

Use case: Number of members.Example: ZCARD leaderboard

$ZRANGEBYSCORE key min max

Use case: Members within a score range: rating bands.Example: ZRANGEBYSCORE leaderboard 1000 2000

$ZREMRANGEBYSCORE key min max

Use case: Delete members in a score range: prune stale entries.Example: ZREMRANGEBYSCORE sessions:active 0 1700000000

Expiration & Keys12

$EXPIRE key 60

Use case: Set a TTL on an existing key: session timeout.Example: EXPIRE session:42 900

$TTL key

Use case: Seconds until expiry: -1 means no TTL.Example: TTL session:42

$PERSIST key

Use case: Remove the TTL: keep a key forever.Example: PERSIST session:42

$KEYS pattern

Use case: Find keys by pattern: DANGER in production (blocking, full scan).Example: KEYS user:*

$SCAN 0 MATCH user:* COUNT 100

Use case: Incrementally scan keys: the safe KEYS alternative.Example: SCAN 0 MATCH user:* COUNT 100

$EXISTS key

Use case: Check if a key exists.Example: EXISTS session:42

$DEL key1 key2

Use case: Delete keys.Example: DEL cache:home cache:about

$TYPE key

Use case: What data type is this key?Example: TYPE user:5

$RENAME old new

Use case: Rename a key.Example: RENAME cache:v1 cache:v2

$RANDOMKEY

Use case: Random key: sampling for debugging.Example: RANDOMKEY

$UNLINK key

Use case: Delete in the background: non-blocking DEL for big values.Example: UNLINK cache:biglist

$COPY key newkey

Use case: Duplicate a key value.Example: COPY user:5 user:5-backup

Pub/Sub & Transactions10

$PUBLISH channel message

Use case: Send a message to all subscribers.Example: PUBLISH news "server deployed"

$SUBSCRIBE channel

Use case: Subscribe and receive messages in real time.Example: SUBSCRIBE news

$PSUBSCRIBE news.*

Use case: Subscribe with a pattern: multi-channel fans.Example: PSUBSCRIBE events.*

$UNSUBSCRIBE channel

Use case: Stop subscribing.Example: UNSUBSCRIBE news

$MULTI

Use case: Start a transaction: commands queue until EXEC.Example: MULTI

$EXEC

Use case: Run all queued commands atomically.Example: MULTI DECR stock:42 INCR sold:42 EXEC

$DISCARD

Use case: Cancel a queued transaction.Example: MULTI INCR x DISCARD

$WATCH key

Use case: Optimistic lock: abort EXEC if the key changes.Example: WATCH balance:5 GET balance:5 ... EXEC

$EVAL script numkeys key1 arg1

Use case: Run a Lua script atomically: complex operations in one shot.Example: EVAL "return redis.call('GET', KEYS[1])" 1 user:5

$SCRIPT LOAD script

Use case: Cache a Lua script: returns its SHA to call later.Example: SCRIPT LOAD "return 1"

Admin & Monitoring14

$PING

Use case: Check connectivity: the redis health check.Example: PING

$SELECT 0

Use case: Switch database index: logical partitions.Example: SELECT 1

$INFO

Use case: Server stats: memory, clients, keyspace.Example: INFO memory

$INFO keyspace

Use case: How many keys in each database.Example: INFO keyspace

$CLIENT LIST

Use case: Show connected clients.Example: CLIENT LIST

$CLIENT KILL ADDR 1.2.3.4:5678

Use case: Disconnect a specific client.Example: CLIENT KILL ADDR 1.2.3.4:5678

$CONFIG GET maxmemory

Use case: Read a config value.Example: CONFIG GET maxmemory

$CONFIG SET maxmemory 512mb

Use case: Change a config at runtime.Example: CONFIG SET maxmemory 512mb

$DBSIZE

Use case: Number of keys in the current database.Example: DBSIZE

$FLUSHDB

Use case: Delete ALL keys in the current database.Example: FLUSHDB

$FLUSHALL

Use case: Delete EVERYTHING in every database.Example: FLUSHALL

$MONITOR

Use case: Stream every command live: debugging, never in production.Example: MONITOR

$SLOWLOG GET 10

Use case: Last 10 slow commands: find the offenders.Example: SLOWLOG GET 10

$SHUTDOWN NOSAVE

Use case: Stop the server without saving.Example: SHUTDOWN NOSAVE

Redis Cheatsheet

Every essential Redis command: strings, hashes, lists, sets, sorted sets, expiration, pub/sub, and transactions, with syntax and real use cases.

Every command shows its syntax with placeholders followed by the use case.

Strings

SET key value: Store a string value.

Example: SET user:1:name "Jane"

GET key: Read a string value.

Example: GET user:1:name

SET key value EX 60: Set with expiration: cache entries that auto-expire.

Example: SET page:home "<html>" EX 300

SET key value NX: Set only if the key does NOT exist: locks and dedup.

Example: SET lock:job 1 NX EX 30

SET key value XX: Set only if the key already exists: update-only.

Example: SET counter:today 5 XX

SETEX key 60 value: Set with expiration in one command.

Example: SETEX otp:user:5 120 "123456"

INCR key: Increment a counter: page views, API usage.

Example: INCR stats:visits

INCRBY key 10: Increment by a specific amount.

Example: INCRBY user:5:score 10

DECR key / DECRBY key 5: Decrement a counter: inventory, tokens.

Example: DECR stock:sku-42

SETNX key value: Set-if-not-exists: the distributed lock primitive.

Example: SETNX lock:deploy 1

GETSET key newvalue: Get the old value AND set a new one atomically.

Example: GETSET last:seen "2026-08-17"

MGET k1 k2 k3: Read multiple keys in one round-trip.

Example: MGET user:1:name user:2:name

MSET k1 v1 k2 v2: Write multiple keys atomically.

Example: MSET user:1:name "Jane" user:1:plan "pro"

APPEND key value: Append to a string value: log builders.

Example: APPEND log:errors "line1 "

STRLEN key: Length of a string value.

Example: STRLEN otp:user:5

GETRANGE key start end: Substring of a value.

Example: GETRANGE token 0 9

GETEX key EX 60: Get a value and set its expiration in one call: touch pattern.

Example: GETEX session:42 EX 900

Hashes

HSET key field value: Set one field of a hash: user profiles.

Example: HSET user:5 name "Jane" plan "pro"

HGET key field: Read one field.

Example: HGET user:5 plan

HGETALL key: Read ALL fields: the full object.

Example: HGETALL user:5

HMGET key f1 f2: Read multiple fields in one call.

Example: HMGET user:5 name email

HINCRBY key field 1: Increment a numeric field inside a hash.

Example: HINCRBY user:5 login_count 1

HDEL key field: Delete a field from a hash.

Example: HDEL user:5 temp_field

HEXISTS key field: Check if a field exists.

Example: HEXISTS user:5 email

HLEN key: Number of fields.

Example: HLEN user:5

HKEYS key: List all field names.

Example: HKEYS user:5

HSETNX key field value: Set a field only if it does not exist.

Example: HSETNX user:5 referrer "google"

HSCAN key 0 MATCH user:* COUNT 100: Incrementally scan hash fields: no blocking HGETALL on huge hashes.

Example: HSCAN user:5 0

Lists

LPUSH key value: Push to the LEFT (head): newest-first lists.

Example: LPUSH notifications:5 "New message"

RPUSH key value: Push to the RIGHT (tail): queue enqueue.

Example: RPUSH jobs:queue "job-123"

LPOP key: Pop from the LEFT: queue dequeue (FIFO).

Example: LPOP jobs:queue

RPOP key: Pop from the RIGHT: LIFO stack.

Example: RPOP undo:stack

BLPOP key 5: Blocking pop with timeout: wait for work instead of polling.

Example: BLPOP jobs:queue 5

BRPOP key 5: Blocking right pop: priority processing.

Example: BRPOP tasks:queue 5

LRANGE key 0 -1: Read the whole list.

Example: LRANGE notifications:5 0 -1

LRANGE key 0 9: First 10 items: pagination.

Example: LRANGE timeline:5 0 9

LLEN key: List length: queue depth.

Example: LLEN jobs:queue

LTRIM key 0 99: Keep only the first 100: cap logs and history.

Example: RPUSH logs "line"; LTRIM logs -100 -1

LINDEX key index: Read an item by index.

Example: LINDEX undo:stack 0

LSET key index value: Overwrite an item by index.

Example: LSET jobs:queue 0 "rerun"

LREM key count value: Remove occurrences of a value.

Example: LREM queue 1 "job-42"

LPUSHX / RPUSHX key value: Push only if the list exists: avoid recreating deleted lists.

Example: RPUSHX jobs:queue "job-1"

RPOPLPUSH source dest: Pop from one list, push to another: processing + retry queue pattern.

Example: RPOPLPUSH jobs:queue processing:queue

Sets & Sorted Sets

SADD key member: Add a member to a set: deduplicated membership.

Example: SADD online:users "user-1"

SMEMBERS key: List all members.

Example: SMEMBERS tags:post:42

SISMEMBER key member: Membership check: is this user online?

Example: SISMEMBER online:users "user-1"

SREM key member: Remove a member.

Example: SREM online:users "user-1"

SCARD key: Set size: online count.

Example: SCARD online:users

SINTER k1 k2: Intersection: mutual followers, common tags.

Example: SINTER followers:1 followers:2

SUNION k1 k2: Union: merge audiences.

Example: SUNION list:a list:b

SDIFF k1 k2: Difference: in k1 but not k2.

Example: SDIFF all:users active:users

SISMEMBER key member: O(1) membership: the reason sets beat lists for checks.

Example: SISMEMBER banned:ips "1.2.3.4"

SADD key member EX 3600: Set member with TTL (Redis 7.4+): temporary membership.

Example: SADD promo:codes "SAVE10" EX 86400

ZADD key score member: Add a member with a score: leaderboards.

Example: ZADD leaderboard 1500 "player-1"

ZINCRBY key 10 member: Increase a member's score: winner moves up.

Example: ZINCRBY leaderboard 10 "player-1"

ZRANGE key 0 -1 WITHSCORES: List members ordered by score.

Example: ZRANGE leaderboard 0 -1 WITHSCORES

ZREVRANGE key 0 9 WITHSCORES: Top 10: reverse order by score.

Example: ZREVRANGE leaderboard 0 9 WITHSCORES

ZRANK key member: A member's position (lowest score = 0).

Example: ZRANK leaderboard "player-1"

ZSCORE key member: A member's score.

Example: ZSCORE leaderboard "player-1"

ZREM key member: Remove a member.

Example: ZREM leaderboard "player-1"

ZCARD key: Number of members.

Example: ZCARD leaderboard

ZRANGEBYSCORE key min max: Members within a score range: rating bands.

Example: ZRANGEBYSCORE leaderboard 1000 2000

ZREMRANGEBYSCORE key min max: Delete members in a score range: prune stale entries.

Example: ZREMRANGEBYSCORE sessions:active 0 1700000000

Expiration & Keys

EXPIRE key 60: Set a TTL on an existing key: session timeout.

Example: EXPIRE session:42 900

TTL key: Seconds until expiry: -1 means no TTL.

Example: TTL session:42

PERSIST key: Remove the TTL: keep a key forever.

Example: PERSIST session:42

KEYS pattern: Find keys by pattern: DANGER in production (blocking, full scan).

Example: KEYS user:*

SCAN 0 MATCH user:* COUNT 100: Incrementally scan keys: the safe KEYS alternative.

Example: SCAN 0 MATCH user:* COUNT 100

EXISTS key: Check if a key exists.

Example: EXISTS session:42

DEL key1 key2: Delete keys.

Example: DEL cache:home cache:about

TYPE key: What data type is this key?

Example: TYPE user:5

RENAME old new: Rename a key.

Example: RENAME cache:v1 cache:v2

RANDOMKEY: Random key: sampling for debugging.

Example: RANDOMKEY

UNLINK key: Delete in the background: non-blocking DEL for big values.

Example: UNLINK cache:biglist

COPY key newkey: Duplicate a key value.

Example: COPY user:5 user:5-backup

Pub/Sub & Transactions

PUBLISH channel message: Send a message to all subscribers.

Example: PUBLISH news "server deployed"

SUBSCRIBE channel: Subscribe and receive messages in real time.

Example: SUBSCRIBE news

PSUBSCRIBE news.*: Subscribe with a pattern: multi-channel fans.

Example: PSUBSCRIBE events.*

UNSUBSCRIBE channel: Stop subscribing.

Example: UNSUBSCRIBE news

MULTI: Start a transaction: commands queue until EXEC.

Example: MULTI

EXEC: Run all queued commands atomically.

Example: MULTI DECR stock:42 INCR sold:42 EXEC

DISCARD: Cancel a queued transaction.

Example: MULTI INCR x DISCARD

WATCH key: Optimistic lock: abort EXEC if the key changes.

Example: WATCH balance:5 GET balance:5 ... EXEC

EVAL script numkeys key1 arg1: Run a Lua script atomically: complex operations in one shot.

Example: EVAL "return redis.call('GET', KEYS[1])" 1 user:5

SCRIPT LOAD script: Cache a Lua script: returns its SHA to call later.

Example: SCRIPT LOAD "return 1"

Admin & Monitoring

PING: Check connectivity: the redis health check.

Example: PING

SELECT 0: Switch database index: logical partitions.

Example: SELECT 1

INFO: Server stats: memory, clients, keyspace.

Example: INFO memory

INFO keyspace: How many keys in each database.

Example: INFO keyspace

CLIENT LIST: Show connected clients.

Example: CLIENT LIST

CLIENT KILL ADDR 1.2.3.4:5678: Disconnect a specific client.

Example: CLIENT KILL ADDR 1.2.3.4:5678

CONFIG GET maxmemory: Read a config value.

Example: CONFIG GET maxmemory

CONFIG SET maxmemory 512mb: Change a config at runtime.

Example: CONFIG SET maxmemory 512mb

DBSIZE: Number of keys in the current database.

Example: DBSIZE

FLUSHDB: Delete ALL keys in the current database.

Example: FLUSHDB

FLUSHALL: Delete EVERYTHING in every database.

Example: FLUSHALL

MONITOR: Stream every command live: debugging, never in production.

Example: MONITOR

SLOWLOG GET 10: Last 10 slow commands: find the offenders.

Example: SLOWLOG GET 10

SHUTDOWN NOSAVE: Stop the server without saving.

Example: SHUTDOWN NOSAVE

Frequently asked questions

How do I set an expiration on a key?

Use EXPIRE <key> <seconds> to set TTL on an existing key, or SET <key> <value> EX <seconds> to set it at write time. Check remaining time with TTL and remove expiration with PERSIST.

What is the difference between lists and sets?

Lists are ordered sequences with duplicates: use them for queues with LPUSH/RPUSH and LPOP/RPOP. Sets are unordered, unique collections: ideal for tags, followers, and membership checks with SADD/SISMEMBER.

How do sorted sets work?

Sorted sets map members to scores and keep them ordered by score: ZADD <key> <score> <member>. They power leaderboards, rate limiters, and range queries with ZRANGE and ZREVRANGE.

How do transactions work in Redis?

MULTI starts a transaction, subsequent commands queue, and EXEC runs them atomically in order. WATCH provides optimistic locking: if a watched key changes before EXEC, the transaction aborts.