NIP-43
======

Relay Access Metadata and Requests
----------------------------------

`draft` `optional`

This NIP defines a way for relays to advertise membership lists, and for clients to request admission to relays on behalf of users.

## Membership Lists

Relays MAY publish a `kind 13534` event which indicates pubkeys that have access to a given relay. This event MUST be signed by the pubkey specified in the `self` field of the relay's [NIP 11](./11.md) document.

The following tags are required:

- A [NIP 70](./70.md) `-` tag
- A `member` tag containing a hex pubkey should be included for each member

This list should not be considered exhaustive or authoritative. To determine membership, both a `kind 13534` event by the relay, and a `kind 10010` event by the member should be consulted.

Example:

```jsonc
{
  "kind": 13534,
  "pubkey": "<nip11.self>",
  "tags": [
    ["-"],
    ["member", "c308e1f882c1f1dff2a43d4294239ddeec04e575f2d1aad1fa21ea7684e61fb5"],
    ["member", "ee1d336e13779e4d4c527b988429d96de16088f958cbf6c074676ac9cfd9c958"]
  ],
  // ...other fields
}
```

## Add User

Relays MAY publish a `kind 8000` event when a member is added to the relay. This event MUST be signed by the pubkey specified in the `self` field of the relay's [NIP 11](./11.md) document.

The following tags are required:

- A [NIP 70](./70.md) `-` tag
- A `p` tag indicating the member's hex pubkey

Example:

```jsonc
{
  "kind": 8000,
  "pubkey": "<nip11.self>",
  "tags": [
    ["-"],
    ["p", "c308e1f882c1f1dff2a43d4294239ddeec04e575f2d1aad1fa21ea7684e61fb5"]
  ],
  // ...other fields
}
```

## Remove User

Relays MAY publish a `kind 8001` event when a member is removed from the relay. This event MUST be signed by the pubkey specified in the `self` field of the relay's [NIP 11](./11.md) document.

The following tags are required:

- A [NIP 70](./70.md) `-` tag
- A `p` tag indicating the member's hex pubkey

Example:

```jsonc
{
  "kind": 8001,
  "pubkey": "<nip11.self>",
  "tags": [
    ["-"],
    ["p", "c308e1f882c1f1dff2a43d4294239ddeec04e575f2d1aad1fa21ea7684e61fb5"]
  ],
  // ...other fields
}
```

## Join Request

A user MAY send a `kind 28934` to a relay in order to request admission. It MUST have a `claim` tag containing an invite code. The event's `created_at` MUST be now, plus or minus a few minutes.

```jsonc
{
  "kind": 28934,
  "pubkey": "<nip11.self>",
  "tags": [
    ["-"],
    ["claim", "<invite code>"]
  ],
  // ...other fields
}
```

Upon receiving a claim, a relay MUST notify the client as to what the status of the claim is using an `OK` message. Failed claims SHOULD use the same standard `"restricted: "` prefix specified by NIP 42.

Relays SHOULD update their `kind 13534` member list and MAY publish a `kind 8000` "add member" event.

Some examples:

```
["OK", <event-id>, false, "restricted: that invite code is expired."]
["OK", <event-id>, false, "restricted: that is an invalid invite code."]
["OK", <event-id>, true, "duplicate: you are already a member of this relay."]
["OK", <event-id>, true, "info: welcome to wss://relay.bunk.skunk!"]
```

## Invite Request

Users may request a claim string from a relay by making a request for `kind 28935` events. This event MUST be signed by the pubkey specified in the `self` field of the relay's [NIP 11](./11.md) document.

```jsonc
{
  "kind": 28935,
  "pubkey": "<nip11.self>",
  "tags": [
    ["-"],
    ["claim", "<invite code>"],
  ],
  // ...other fields
}
```

Note that these events are in the `ephemeral` range, which means relays must explicitly opt-in to this behavior by generating claims on the fly when requested. This allows relays to improve security by issuing a different claim for each request, only issuing claims to certain users, or expiring claims.

## Leave Request

A user MAY send a `kind 28936` to a relay in order to request that their access be revoked. The event's `created_at` MUST be now, plus or minus a few minutes. This event MUST include a [NIP 70](./70.md) `-` tag.

```jsonc
{
  "kind": 28936,
  "tags": [["-"]],
  // ...other fields
}
```

Relays SHOULD update their `kind 13534` member list and MAY publish a `kind 8001` "remove member" event.