NIP-48

Proxy Tags - marks events that were bridged from other protocols (ActivityPub, AT Protocol, RSS, etc.) using a proxy tag containing the original ID and protocol name.

Import

import { nip48 } from 'nostr-core'
// or import individual functions
import {
  addProxyTag,
  getProxyTags,
  isProxied,
  getProxyByProtocol,
} from 'nostr-core'

ProxyTag Type

type ProxyProtocol = 'activitypub' | 'atproto' | 'rss' | 'web' | string
type ProxyTag = { id: string; protocol: ProxyProtocol }

nip48.addProxyTag

function addProxyTag(tags: string[][], id: string, protocol: ProxyProtocol): string[][]

Adds a proxy tag to event tags.

const tags = nip48.addProxyTag([], 'https://mastodon.social/@user/123', 'activitypub')

nip48.getProxyTags

function getProxyTags(event: NostrEvent | EventTemplate): ProxyTag[]

Gets all proxy tags from an event.

const proxies = nip48.getProxyTags(event)
// [{ id: 'https://mastodon.social/@user/123', protocol: 'activitypub' }]

nip48.isProxied

function isProxied(event: NostrEvent | EventTemplate): boolean

Checks if an event was bridged from another protocol.

nip48.getProxyByProtocol

function getProxyByProtocol(event: NostrEvent | EventTemplate, protocol: ProxyProtocol): ProxyTag | undefined

Gets the first proxy tag matching a specific protocol.

const ap = nip48.getProxyByProtocol(event, 'activitypub')
if (ap) console.log(`Bridged from: ${ap.id}`)

How It Works

• The proxy tag format is ['proxy', id, protocol]
• Common protocols: activitypub, atproto, rss, web
• The ID is the original identifier in the source protocol (e.g., ActivityPub URL)
• Bridges use this to indicate an event originated outside of Nostr
• Clients can use this to link back to the original source
• An event can have multiple proxy tags if bridged through multiple protocols