Tag: proxy

Overview

The proxy tag links Nostr events to their original source from other protocols. It allows Nostr events bridged from other protocols (such as ActivityPub, AT Protocol, RSS, or the Web) to reference back to the source object.

Specification

Property	Value
Tag Name	proxy
Defined in	NIP-48
Required for	Can be used with any event kind

Format

["proxy", "<id>", "<protocol>"]

Where:

• <id> is the ID of the source object, with format varying by protocol
• <protocol> is the name of the protocol (e.g., "activitypub")

Usage Description

The proxy tag indicates that an event did not originate on the Nostr protocol but was bridged from elsewhere on the web. It provides the original ID and protocol source.

The ID must be universally unique, regardless of the protocol, and its format depends on the protocol being used.

Supported Protocols

Protocol	ID format	Example
activitypub	URL	https://gleasonator.com/objects/9f524868-c1a0-4ee7-ad51-aaa23d68b526
atproto	AT URI	at://did:plc:zhbjlbmir5dganqhueg7y4i3/app.bsky.feed.post/3jt5hlibeol2i
rss	URL with guid fragment	https://soapbox.pub/rss/feed.xml#https%3A%2F%2Fsoapbox.pub%2Fblog%2Fmostr-fediverse-nostr-bridge
web	URL	https://twitter.com/jack/status/20

Examples

Example with ActivityPub Source

[
  "proxy",
  "https://gleasonator.com/objects/8f6fac53-4f66-4c6e-ac7d-92e5e78c3e79",
  "activitypub"
]

Example with Web Source

[
  "proxy",
  "https://twitter.com/jack/status/20",
  "web"
]

Complete Event Example

{
  "kind": 1,
  "content": "I'm vegan btw",
  "tags": [
    [
      "proxy",
      "https://gleasonator.com/objects/8f6fac53-4f66-4c6e-ac7d-92e5e78c3e79",
      "activitypub"
    ]
  ],
  "pubkey": "79c2cae114ea28a981e7559b4fe7854a473521a8d22a66bbab9fa248eb820ff6",
  "created_at": 1691091365,
  "id": "55920b758b9c7b17854b6e3d44e6a02a83d1cb49e1227e75a30426dea94d4cb2",
  "sig": "a72f12c08f18e85d98fb92ae89e2fe63e48b8864c5e10fbdd5335f3c9f936397a6b0a7350efe251f8168b1601d7012d4a6d0ee6eec958067cf22a14f5a5ea579"
}

Client Behavior

Clients may use this information to:

• Reconcile duplicated content bridged from other protocols
• Display a link to the source object
• Visually indicate that the content originated from another platform

Relay Behavior

No specific relay behavior is defined for events with proxy tags. Relays should process these events normally.

References

• NIP-48: Proxy Tags
• FEP-fffd: Proxy Objects
• Mostr bridge - A bridge between ActivityPub and Nostr

Related Tags

No directly related tags at this time.

Notes

The list of supported protocols may be extended in the future as more bridges to other protocols are developed.