SET

SET stores value at key. If the key already holds a value, of any type, it is overwritten and any existing time to live is cleared, unless you pass KEEPTTL.

Options

Option	Effect
NX	Set only if the key does not exist.
XX	Set only if the key already exists.
IFEQ value	Set only if the key holds a string equal to value.
IFNE value	Set only if the key does not hold a string equal to value. A missing key is not equal to anything, so it is set.
IFDEQ digest	Set only if the DIGEST of the key’s string equals digest.
IFDNE digest	Set only if the digest of the key’s string does not equal digest.
GET	Return the previous string value (or nil) instead of OK.
EX seconds	Expire after this many seconds.
PX milliseconds	Expire after this many milliseconds.
EXAT unix-time-seconds	Expire at this Unix time, in seconds.
PXAT unix-time-milliseconds	Expire at this Unix time, in milliseconds.
KEEPTTL	Keep the key’s current time to live.

NX, XX and the four conditions IFEQ, IFNE, IFDEQ and IFDNE exclude one another: give at most one of them, or the reply is ERR syntax error. Only one of EX, PX, EXAT, PXAT and KEEPTTL can be given. Expiry values must be positive integers. An absolute time that is already in the past deletes the key instead of setting it.

Return value

Case	RESP2	RESP3
Value stored	Simple string OK	Simple string OK
Not stored because of NX, XX or a condition	Nil bulk string	Null
With GET	The old value as a bulk string, or nil if the key did not exist	The old value, or null

With GET, SET replies with a WRONGTYPE error if the key holds a value that is not a string, and nothing is stored. With a condition and GET, the old string comes back whether or not the condition held. A condition on a key that holds another type is WRONGTYPE too.

Examples

127.0.0.1:6379> SET greeting "hello"
OK
127.0.0.1:6379> SET greeting "hi" NX
(nil)
127.0.0.1:6379> SET greeting "hi" XX GET
"hello"
127.0.0.1:6379> SET session:42 "token" EX 3600
OK
127.0.0.1:6379> TTL session:42
(integer) 3600
127.0.0.1:6379> SET lock owner-a
OK
127.0.0.1:6379> SET lock owner-b IFEQ owner-x
(nil)
127.0.0.1:6379> SET lock owner-b IFEQ owner-a
OK
127.0.0.1:6379> SET lock owner-c IFNE owner-b
(nil)
127.0.0.1:6379> SET lock owner-d GET IFEQ nothing
"owner-b"

A condition lets you replace a value only when nobody else changed it since you read it. IFDEQ and IFDNE compare the digest, so you do not have to send the old value.

Compatibility

Same options and replies as Redis 7 and Valkey 8, plus Redis 8.4’s IFEQ, IFNE, IFDEQ and IFDNE. For expiry with nanosecond precision, see NEXPIRE.

See also

GET, GETEX, SETNX, MSET, EXPIRE