How to Use EXPIRE Command in Redis for Key Expiration

Use the EXPIRE command in Redis to set a time-to-live (TTL) in seconds on a key, after which Redis will automatically delete it. The syntax is EXPIRE key seconds, where key is the name of the key and seconds is the expiration time.

Syntax

The EXPIRE command sets a timeout on a key in seconds. After the timeout, the key is deleted automatically.

• key: The name of the key you want to expire.
• seconds: The time in seconds before the key expires.

redis

EXPIRE key seconds

Example

This example shows how to set a key with a value and then set it to expire after 10 seconds.

redis

SET mykey "Hello"
EXPIRE mykey 10
TTL mykey

Output

OK
(integer) 1
(integer) 10

Common Pitfalls

Common mistakes include:

• Setting expiration on a key that does not exist returns 0 and does nothing.
• Using EXPIRE with a negative or zero time deletes the key immediately.
• Forgetting that expiration time is in seconds, not milliseconds.

redis

EXPIRE nonexistingkey 10
# Returns 0 because key does not exist

EXPIRE mykey 0
# Deletes the key immediately

Output

(integer) 0
(integer) 1

Quick Reference

Command	Description	Return Value
EXPIRE key seconds	Set expiration time in seconds	1 if timeout set, 0 if key does not exist
TTL key	Get remaining time to live in seconds	Remaining seconds or -1 if no timeout
PERSIST key	Remove expiration from key	1 if timeout removed, 0 if key does not exist or has no timeout

Key Takeaways

Use EXPIRE to set a time-to-live on keys in seconds.

EXPIRE returns 1 if successful, 0 if the key does not exist.

Expiration time is in seconds, not milliseconds.

Keys expire automatically after the timeout and are deleted.

Use TTL to check remaining time before expiration.