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Kind 34550: Community Definition ​

Overview ​

Community Definition events (kind 34550) establish moderated communities in the Nostr ecosystem. These parameterized replaceable events define the structure, purpose, and governance of Reddit-style communities where users can post content that is subject to moderation. Each community has a unique identity, description, and a list of designated moderators who can approve or reject posts.

Specification ​

PropertyValue
Kind Number34550
Event RangeParameterized Replaceable
Defined inNIP-72

Content Format ​

The content field typically contains additional information about the community or can be left empty if all relevant information is in the tags.

Schema ​

json
"content": "This community is dedicated to discussing developments in the Nostr protocol and ecosystem."

Tags ​

Tag NameDescriptionFormatRequired
dCommunity identifier["d", "<community-d-identifier>"]Yes
nameHuman-readable name["name", "<community-name>"]No
descriptionCommunity description["description", "<community-description>"]No
imageCommunity image URL["image", "<url>", "<width>x<height>"]No
pModerator public key["p", "<pubkey>", "<relay-url>", "moderator"]No
relayCommunity relay["relay", "<relay-url>", "<optional-role>"]No
rulesCommunity rules["rules", "<rules-text>"]No
topicCommunity topic["topic", "<topic-name>"]No

Client Behavior ​

Clients should:

  1. Display community information in a recognizable format
  2. Show the name tag value as the community name if present, otherwise use the d tag
  3. Present the list of moderators and their roles
  4. Allow users to browse communities and view posts made to them
  5. When submitting posts to communities:
    • Add an a tag referencing the community using format: 34550:<pubkey>:<d-identifier>
    • Include a relay hint to help others find the community definition
  6. For moderation functions:
    • Allow moderators to issue approval events (kind 4550) for posts
    • Show only approved posts when viewing a moderated community
    • Support filtering approved posts by kind using the k tag

Relay Behavior ​

Relays should:

  1. Handle kind 34550 events as parameterized replaceable events with the d tag as discriminator
  2. Store these events to allow clients to discover communities
  3. When supporting NIP-72 communities, store approval events (kind 4550) for moderation

Use Cases ​

  • Creating topic-based discussion communities
  • Building moderated spaces for content curation
  • Establishing shared interest groups
  • Creating specialized knowledge-sharing forums
  • Supporting community governance and moderation
  • Enabling discovery of quality content by topic
  • Building Reddit-style community structures

Example ​

json
{
  "id": "c6903a5204c8a9c1c2a33cae7f184dc7083bb10c9d15329d9afa0b430180a2eb",
  "pubkey": "32e1827635450ebb3c5a7d12c1f8e7b2b514439ac10a67eef3d9fd9c5c68e245",
  "created_at": 1684323900,
  "kind": 34550,
  "tags": [
    ["d", "nostr-dev"],
    ["name", "Nostr Development"],
    ["description", "A community for discussing Nostr protocol development, client implementations, and relay operations."],
    ["image", "https://example.com/nostr-dev-logo.png", "500x500"],
    ["p", "3bf0c63fcb93463407af97a5e5ee64fa883d107ef9e558472c4eb9aaaefa459d", "wss://relay.damus.io", "moderator"],
    ["p", "32e1827635450ebb3c5a7d12c1f8e7b2b514439ac10a67eef3d9fd9c5c68e245", "wss://relay.nostr.band", "moderator"],
    ["relay", "wss://relay.nostr.band", "requests"],
    ["relay", "wss://relay.damus.io", "approvals"],
    ["rules", "1. Be respectful. 2. Stay on topic. 3. No spam. 4. Share code examples when possible."],
    ["topic", "development"],
    ["topic", "protocol"]
  ],
  "content": "This community is for Nostr developers to discuss protocol improvements, client implementations, relay operations, and all technical aspects of the Nostr ecosystem.",
  "sig": "87b1863f65a0a3a36b235cc78dad747cc9584d64b8e2a195ed83f2d0a54c85daa8a682a096ebd968f6d16cfd0ac3ab867269f92c0e127a782cf51b04c18a5dce"
}

Community Posting Process ​

The posting process in a NIP-72 community consists of three main steps:

  1. Creating a Post: Users submit an event (of any kind) with an a tag referencing the community:

    json
    {
  "kind": 1,
  "tags": [
    ["a", "34550:32e1827635450ebb3c5a7d12c1f8e7b2b514439ac10a67eef3d9fd9c5c68e245:nostr-dev", "wss://relay.nostr.band"]
  ],
  "content": "Has anyone implemented NIP-72 communities in their client yet?"
}

  2. Moderation Approval: Moderators issue an approval event (kind 4550):

    json
    {
  "kind": 4550,
  "tags": [
    ["a", "34550:32e1827635450ebb3c5a7d12c1f8e7b2b514439ac10a67eef3d9fd9c5c68e245:nostr-dev", "wss://relay.nostr.band"],
    ["e", "<post-event-id>", "<relay-url>"],
    ["p", "<post-author-pubkey>", "<relay-url>"],
    ["k", "1"]
  ],
  "content": "<JSON-encoded original post event>"
}

  3. Content Display: Clients show only approved posts when viewing the community.

References ​

Notes ​

  • The d tag is required for parameterized replaceable events to work correctly
  • Community identifiers should be chosen carefully, as they become part of the community's identity
  • The name tag is preferred for display over the d tag when available
  • Relay tags may include specialized roles:
    • author: Relay hosting the community author's kind 0 profile
    • requests: Relay for sending and receiving post requests
    • approvals: Relay for sending and receiving approval events
  • Moderator roles may be expanded in the future to include different privilege levels
  • Clients may implement different UX approaches for community interaction
  • Posts can be cross-posted to multiple communities using appropriate a tags
  • Replaceable events can be approved in three ways as specified in NIP-72:
    1. Using an e tag to approve a specific version
    2. Using an a tag to approve all future versions
    3. Using both e and a tags for complete history