nips/51.md

NIP-51

Lists

draft optional author:fiatjaf author:arcbtc author:monlovesmango author:eskema author:gzuuus

This NIP defines lists of things that users can create. Lists can contain references to anything, and these references can be public or private.

Public items in a list are specified in the event tags array, while private items are specified in a JSON array that mimics the structure of the event tags array, but stringified and encrypted using the same scheme from NIP-04 (the shared key is computed using the author's public and private key) and stored in the .content.

Types of lists

Standard lists

Standard lists use non-parameterized replaceable events, meaning users may only have a single list of each kind. They have special meaning and clients may rely on them to augment a user's profile or browsing experience.

For example, mute lists can contain the public keys of spammers and bad actors users don't want to see in their feeds or receive annoying notifications from.

name	kind	description	expected tag items
Mute list	10000	things the user doesn't want to see in their feeds	"p" (pubkeys), "t" (hashtags), "word" (lowercase string), "e" (threads)
Pinned notes	10001	events the user intends to showcase in their profile page	"e" (kind:1 notes)
Bookmarks	10003	uncategorized, "global" list of things a user wants to save	"e" (kind:1 notes), "a" (kind:30023 articles), "t" (hashtags), "r" (URLs)
Communities	10004	NIP-72 communities the user belongs to	"a" (kind:34550 community definitions)
Public chats	10005	NIP-28 chat channels the user is in	"e" (kind:40 community definitions)
Blocked relays	10006	relays clients should never connect to	"relay" (relay URLs)
Search relays	10007	relays clients should use when performing search queries	"relay" (relay URLs)
Interests	10015	topics a user may be interested in and pointers	"t" (hashtags) and "a" (kind:30015 interest set)
Emojis	10030	user preferred emojis and pointers to emoji sets	"emoji" (see NIP-30) and "a" (kind:30030 emoji set)

Sets

Sets are lists with well-defined meaning that can enhance the functionality and the UI of clients that rely on them. Unlike standard lists, users are expected to have more than one set of each kind, therefore each of them must be assigned a different "d" identifier.

For example, relay sets can be displayed in a dropdown UI to give users the option to switch to which relays they will publish an event or from which relays they will read the replies to an event; curation sets can be used by apps to showcase curations made by others tagged to different topics.

Aside from their main identifier, the "d" tag, sets can optionally have a "name", a "picture" and an "about" tag that can be used to enhance their UI.

name	kind	description	expected tag items
Follow sets	30000	categorized groups of users a client may choose to check out in different circumstances	"p" (pubkeys)
Relay sets	30002	user-defined relay groups the user can easily pick and choose from during various operations	"relay" (relay URLs)
Bookmark sets	30003	user-defined bookmarks categories , for when bookmarks must be in labeled separate groups	"e" (kind:1 notes), "a" (kind:30023 articles), "t" (hashtags), "r" (URLs)
Curation sets	30004	groups of articles picked by users as interesting and/or belonging to the same category	"a" (kind:30023 articles), "e" (kind:1 notes)
Interest sets	30015	interest topics represented by a bunch of "hashtags"	"t" (hashtags)
Emoji sets	30030	categorized emoji groups	"emoji" (see NIP-30)

Deprecated standard lists

Some clients have used these lists in the past, but they should work on transitioning to the standard formats above.

kind	"d" tag	use instead
30000	"mute"	kind 10000 mute list
30001	"pin"	kind 10001 pin list
30001	"bookmark"	kind 10003 bookmarks list
30001	"communities"	kind 10004 communities list

Examples

A mute list with some public items and some encrypted items

{
  "id": "a92a316b75e44cfdc19986c634049158d4206fcc0b7b9c7ccbcdabe28beebcd0",
  "pubkey": "854043ae8f1f97430ca8c1f1a090bdde6488bd5115c7a45307a2a212750ae4cb",
  "created_at": 1699597889,
  "kind": 10000,
  "tags": [
    ["p", "07caba282f76441955b695551c3c5c742e5b9202a3784780f8086fdcdc1da3a9"],
    ["p", "a55c15f5e41d5aebd236eca5e0142789c5385703f1a7485aa4b38d94fd18dcc4"]
  ],
  "content": "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?iv=S3rFeFr1gsYqmQA7bNnNTQ==",
  "sig": "1173822c53261f8cffe7efbf43ba4a97a9198b3e402c2a1df130f42a8985a2d0d3430f4de350db184141e45ca844ab4e5364ea80f11d720e36357e1853dba6ca"
}

A curation set of articles and notes about yaks

{
  "id": "567b41fc9060c758c4216fe5f8d3df7c57daad7ae757fa4606f0c39d4dd220ef",
  "pubkey": "d6dc95542e18b8b7aec2f14610f55c335abebec76f3db9e58c254661d0593a0c",
  "created_at": 1695327657,
  "kind": 30004,
  "tags": [
    ["d", "jvdy9i4"],
    ["name", "Yaks"],
    ["picture", "https://cdn.britannica.com/40/188540-050-9AC748DE/Yak-Himalayas-Nepal.jpg"],
    ["about", "The domestic yak, also known as the Tartary ox, grunting ox, or hairy cattle, is a species of long-haired domesticated cattle found throughout the Himalayan region of the Indian subcontinent, the Tibetan Plateau, Gilgit-Baltistan, Tajikistan and as far north as Mongolia and Siberia."],
    ["a", "30023:26dc95542e18b8b7aec2f14610f55c335abebec76f3db9e58c254661d0593a0c:95ODQzw3ajNoZ8SyMDOzQ"],
    ["a", "30023:54af95542e18b8b7aec2f14610f55c335abebec76f3db9e58c254661d0593a0c:1-MYP8dAhramH9J5gJWKx"],
    ["a", "30023:f8fe95542e18b8b7aec2f14610f55c335abebec76f3db9e58c254661d0593a0c:D2Tbd38bGrFvU0bIbvSMt"],
    ["e", "d78ba0d5dce22bfff9db0a9e996c9ef27e2c91051de0c4e1da340e0326b4941e"]
  ],
  "content": "",
  "sig": "a9a4e2192eede77e6c9d24ddfab95ba3ff7c03fbd07ad011fff245abea431fb4d3787c2d04aad001cb039cb8de91d83ce30e9a94f82ac3c5a2372aa1294a96bd"
}

Encryption process pseudocode

val private_items = [
  ["p", "07caba282f76441955b695551c3c5c742e5b9202a3784780f8086fdcdc1da3a9"],
  ["a", "a55c15f5e41d5aebd236eca5e0142789c5385703f1a7485aa4b38d94fd18dcc4"],
]
val base64blob = nip04.encrypt(json.encode_to_string(private_items))
event.content = base64blob