nips/68.md

NIP-68
======

Shared Replaceables
-------------------

`draft` `optional`

This NIP creates replaceable events that can be changed by any public key in the list of pre-defined owners. 

The initial creator adds all owners to the `d` tag, separated by `|`. The presence of `|` on the `d` tag, with valid keys for each but the last position, directs clients to work with this event as a shared replaceable. 

```js
{
  "kind": 3xxxx,
  "tags": [
    ["d", "<pubkey1>|<pubkey2>|<pubkey3>|<identifier>"],
    // ...
  ],
  //...
}
```

Clients MUST render the latest event from any of the owners. 

To change owners, users MUST create a new `d` tag with new owners and MAY delete the previous one. 

# Referencing & Indexing

Events that reference the most recent version of a shared replaceable MUST add `a` tags to each owner. 

Reply example:

```jsonc
{
  "kind": 1,
  "tags": [
    ["a", "3xxxx:<pubkey1>:<pubkey1>|<pubkey2>|<pubkey3>|<identifier>", "<optional-relay-url>", "reply"],
    ["a", "3xxxx:<pubkey2>:<pubkey1>|<pubkey2>|<pubkey3>|<identifier>", "<optional-relay-url>", "reply"],
    ["a", "3xxxx:<pubkey3>:<pubkey1>|<pubkey2>|<pubkey3>|<identifier>", "<optional-relay-url>", "reply"]
  ],
  "content": "a reply",
  // ...
}
```

## Deletion

Owners can only unilaterally delete their own events: 

```jsonc
{
  "pubkey": "<pubkey1>",
  "kind": 5, 
  "tags": [
    ["a", "3xxxx:<pubkey1>:<pubkey1>|<pubkey2>|<pubkey3>|<identifier>", "<optional-relay-url>"],
  ],
  "content": "Deletes my versions of this repleceable",
  // ...
}
```

Adding other pubkeys to the `a` tag won't have any effect. 

# Filtering

After parsing the desired `d` tag, clients SHOULD create a filter that includes all `d`-tag pubkeys as authors and use the `limit:1` to get only the latest event. 

```json
{
  "authors": ["<pubkey1>", "<pubkey2>", "<pubkey3>"],
  "kinds": [3xxxx],
  "#d": ["<pubkey1>|<pubkey2>|<pubkey3>|<identifier>"],
  "limit": 1
}
```

To find all events associated with a given shared replaceable, clients SHOULD search for `a` tags from each of the authors: 

```json
{
  "#a": [
    "3xxxx:<pubkey1>:<pubkey1>|<pubkey2>|<pubkey3>|<identifier>", 
    "3xxxx:<pubkey2>:<pubkey1>|<pubkey2>|<pubkey3>|<identifier>", 
    "3xxxx:<pubkey3>:<pubkey1>|<pubkey2>|<pubkey3>|<identifier>"
  ]
}
```