The Redis PEXPIRETIME command returns the absolute Unix timestamp in milliseconds at which the given key will expire. This is the number of milliseconds since 00:00:00 UTC on 1 January 1970 until the expiry time of the key.

This works exactly the same as EXPIRETIME, but it returns the Unix timestamp in milliseconds instead of seconds.

The PEXPIRETIME command was introduced in Redis 7.0.0.

Syntax

The syntax goes like this:

PEXPIRETIME key

Where key is the key for which to get the expiry time.

Example

Suppose we set a key with an expiry:

SET dinner "Pasta" PX 86400000

Result:

OK

Here, I used the PX argument of the SET command to set an expiry in milliseconds. I could have alternatively used the EX argument to set it in milliseconds. Either way, it wouldn’t change the results we get with PEXPIRETIME (assuming the same expiry time).

Another way to do it would be with the EXPIRE or EXPIREAT commands (for seconds), or with the PEXPIRE or PEXPIREAT commands (for milliseconds).

Anyway, we can now use the PEXPIRETIME command to check that key’s expiry time in Unix time:

PEXPIRETIME dinner

Result:

(integer) 1655949518046

This is the absolute Unix timestamp of the key’s expiry. If we run the statement again at a later time, we get exactly the same result:

PEXPIRETIME dinner

Result:

(integer) 1655949518046

The absolute Unix timestamp of the key’s expiry is not to be confused with the current time to live (TTL) of the key.

Let’s run the PTTL command against it to check its time to live in milliseconds:

PTTL dinner

Result:

(integer) 86324550

We get an integer reply with the current time to live (in milliseconds). If we run the same command again, we get a different result, due to the expiry getting nearer (and therefore, the time to live getting shorter):

PTTL dinner

Result:

(integer) 86302301

This is in contrast to the absolute Unix timestamp of the expiry.

There’s also a TTL command that returns the time to live in seconds.

Keys Without an Expiry

If the key has no expiry, PEXPIRETIME returns an integer reply of -1.

To test this, let’s remove the expiry of our key:

PERSIST dinner

Result:

(integer) 1

The PERSIST command removes any timeout on the given key. We got an integer reply of 1, which means that it successfully removed the timeout on our key.

Now let’s run PEXPIRETIME against that key:

PEXPIRETIME dinner

Result:

(integer) -1

As expected, we get an integer reply of -1, which means that the key doesn’t have an expiry set.

Non-Existent Keys

If the key doesn’t exist, PEXPIRETIME returns an integer reply of -2.

Let’s delete our key:

DEL dinner

Result:

(integer) 1

The key has been deleted.

And now let’s try to run PEXPIRETIME against the deleted key:

PEXPIRETIME dinner

Result:

(integer) -2

As expected, an integer reply of -2.