NIP-40

Expiration Timestamp

draft optional author:0xtlt

The expiration tag enables users to specify a timestamp at UTC-0 at which the message should be considered expired and deleted by relays (or just ignored by clients). This can be useful for making temporary announcements, making limited-time offers, or sending ephemeral messages but should not be seen as a security solution for the content of your messages. So be careful when sharing confidential information.

Spec

tag: expiration
options:
 - [UNIX timestamp in seconds]: required

Example

{
    "pubkey": "<pub-key>",
    "created_at": 1000000000,
    "kind": 1,
    "tags": [
      ["expiration", "1600000000"]
    ],
    "content": "This message will expire at the specified timestamp and be deleted by relays.\n",
    "id": "<event-id>"
}

Note: The timestamp should be in the same format as the created_at timestamp and should be interpreted as the time at which the message should be deleted by relays.

Client Behavior

Clients SHOULD use the supported_nips field to learn if a relay supports this NIP. Clients SHOULD NOT send expiration events to relays that do not support this NIP.

Clients MUST ignore events that have expired.

Relay Behavior

Relays SHOULD NOT delete an expired message immediately on expiration. Relays that wish to purge expired messages from their DB should allow for a grace period before deletion. For example, this could be 24h after event expiration. Relays MAY choose to not delete expired messages.

Suggested Use Cases

Temporary announcements - This tag can be used to make temporary announcements. For example, an event organizer could use this tag to post announcements about an upcoming event.
Limited-time offers - This tag can be used by businesses to make limited-time offers that expire after a certain amount of time. For example, a business could use this tag to make a special offer that is only available for a limited time.

One last time, be careful!

The events could be downloaded by third parties as they are publicly accessible all the time on the relays. So don't consider expiring messages as a security feature for your conversations or other uses.

2.3 KiB Raw Blame History