TTL

Syntax

TTL key

Description

The TTL command returns the remaining time to live of a key in seconds. It returns different values depending on the key's state.

Arguments

• key (required): The name of the key to check.

Return Value

Returns an Integer:

• Positive integer: The remaining TTL in seconds
• -1: The key exists but has no expiration set
• -2: The key does not exist

Examples

Key with Expiration

SET mykey "value"
EXPIRE mykey 3600
TTL mykey

Response:

OK
(integer) 1
(integer) 3600

Key Without Expiration

SET mykey "value"
TTL mykey

Response:

OK
(integer) -1

Non-Existent Key

TTL nonexistent

Response:

(integer) -2

TTL Decreases Over Time

SET mykey "value"
EXPIRE mykey 10
TTL mykey
# Wait a few seconds
TTL mykey

Response:

OK
(integer) 1
(integer) 10
(integer) 7  # After 3 seconds

Expired Key

SET mykey "value"
EXPIRE mykey 1
# Wait 1 second
TTL mykey

Response:

OK
(integer) 1
(integer) -2  # Key has expired and been deleted

Return Value Meanings

Notes

• TTL is returned in seconds
• The value decreases over time as the expiration approaches
• Returns -1 if the key exists but has no expiration
• Returns -2 if the key doesn't exist or has expired
• Works with both string and list keys

Use Cases

• Monitoring: Check how much time is left before a key expires
• Debugging: Verify that expiration is set correctly
• Conditional Logic: Check if a key will expire soon
• Cache Management: Monitor cache expiration times

Related Commands

• EXPIRE - Set a timeout on a key
• PERSIST - Remove the expiration from a key
• EXISTS - Check if a key exists