NIP-28

Public Chat - defines channel-based public chat using kind 40 (channel creation), kind 41 (channel metadata), kind 42 (channel messages), kind 43 (hide message), and kind 44 (mute user).

Import

import { nip28 } from 'nostr-core'
// or import individual functions
import {
  createChannelEventTemplate,
  createChannelEvent,
  createChannelMetadataEventTemplate,
  createChannelMetadataEvent,
  createChannelMessageEventTemplate,
  createChannelMessageEvent,
  createChannelHideMessageEventTemplate,
  createChannelMuteUserEventTemplate,
  parseChannelMetadata,
  parseChannelMessage,
} from 'nostr-core'

ChannelMetadata Type

type ChannelMetadata = {
  name: string
  about?: string
  picture?: string
}

nip28.createChannelEvent

function createChannelEvent(metadata: ChannelMetadata, secretKey: Uint8Array): NostrEvent

Creates and signs a kind 40 channel creation event.

const channel = nip28.createChannelEvent(
  { name: 'General', about: 'General discussion', picture: 'https://example.com/pic.png' },
  secretKey,
)
const channelId = channel.id // Use this to reference the channel

nip28.createChannelMetadataEvent

function createChannelMetadataEvent(channelId: string, metadata: ChannelMetadata, secretKey: Uint8Array, recommendedRelay?: string): NostrEvent

Creates a kind 41 channel metadata update event. Only the channel creator should update metadata.

const update = nip28.createChannelMetadataEvent(
  channelId,
  { name: 'Updated Name', about: 'New description' },
  secretKey,
)

nip28.createChannelMessageEvent

function createChannelMessageEvent(channelId: string, content: string, secretKey: Uint8Array, recommendedRelay?: string, replyTo?: string): NostrEvent

Creates a kind 42 channel message. Optionally replies to another message.

const msg = nip28.createChannelMessageEvent(channelId, 'Hello everyone!', secretKey)

// Reply to a message
const reply = nip28.createChannelMessageEvent(channelId, 'Great point!', secretKey, undefined, msg.id)

nip28.createChannelHideMessageEventTemplate

function createChannelHideMessageEventTemplate(messageId: string, reason?: string): EventTemplate

Creates a kind 43 event to hide a channel message (moderation).

nip28.createChannelMuteUserEventTemplate

function createChannelMuteUserEventTemplate(pubkey: string, reason?: string): EventTemplate

Creates a kind 44 event to mute a user in a channel (moderation).

nip28.parseChannelMetadata

function parseChannelMetadata(event: NostrEvent): ChannelMetadata

Parses channel metadata from a kind 40 or 41 event.

nip28.parseChannelMessage

function parseChannelMessage(event: NostrEvent): { channelId?: string; content: string; replyTo?: string }

Parses a kind 42 channel message event.

How It Works

• Kind 40 creates a channel - the event ID becomes the channel ID
• Kind 41 updates channel metadata - must reference the channel via e tag
• Kind 42 sends a message - references the channel as root and optionally a message as reply
• Kind 43 hides a message (moderator action)
• Kind 44 mutes a user (moderator action)
• Channel metadata is stored as JSON in the content field
• Messages use NIP-10 style e tag markers (root/reply)