nips/22.md

NIP-22
======

Unacceptable Event `created_at` time
---------------------------

`draft` `optional` `author:jeffthibault`

Relays may support notifying clients that the event they published has an unacceptable `created_at` time. A relay will consider the `created_at` time unacceptable if the `created_at` time is more than **[limit]** before the event was received by the relay (in the past) OR if the `created_at` time is later than the time the event was received by the relay (in the future). 

If a relay supports this NIP, the relay SHOULD send the client a `NOTICE` message saying the event was not stored because the `created_at` time was unacceptable.

Client Behavior
---------------

Clients SHOULD use the `supported_nips` field to learn if a relay supports event `created_at` time checks.

Motivation
----------

The motivation for this NIP is to prevent clients from saying they published an event *significantly* earlier than they actually did or saying they published an event in the future.

The event `created_at` field is just a unix timestamp (integer) so one could set it to a time in the past or future. For example, the `created_at` field could be set to a time 10 years ago even though it was created today and it could still be a valid event. One could also set the `created_at` field to a time 10 years in the future and it could still be a valid event. This NIP aims to set a maximum amount of time elapsed between when an event was created and when it was *actually* published and prevent events from being from the future.

Relay Logic
-----------

```
if time.now - event.created_at > limit OR event.created_at > time.now:
  send NOTICE
```