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+NIP-XX
+======
+
+Rooms
+-----
+
+`draft` `optional`
+
+# Rooms
+
+A `room` is identified by an arbitrary, human-readable string no longer than
+30 characters and referred to using a `~` tag indicating the room id and a
+relay url. Rooms on different relays with the same name ARE NOT the same room.
+
+Any event MAY be posted to a `room` using a `~` tag. Events posted to a room
+MUST NOT be considered valid unless their `~` tag matches the current relay, or
+a relay specified in a `kind 30209` federation event.
+
+# Chat
+
+A chat message is a kind `209` event with a `~` tag. Chat messages are intended
+to be used as a high-frequency, informal, context-aware communication medium.
+
+```json
+{
+  "kind": 209,
+  "content": "GM",
+  "tags": [
+    ["~", "Good Morning", "wss://relay.example.com/"],
+  ]
+}
+```
+
+Replies to kind `209` MUST use [NIP-73](https://github.com/nostr-protocol/nips/pull/1233)
+kind `1111` comments with a matching `~` tag. Clients SHOULD encourage flat reply
+hierarchies.
+
+# Threads
+
+A thread is a kind `309` event with a `~` tag. Threads and their replies are
+intended to be used as a low-frequency, more formal, context-aware communication
+medium. Threads MUST include a `title` with a summary of the `content`.
+
+```json
+{
+  "kind": 309,
+  "content": "GM",
+  "tags": [
+    ["~", "Good Morning", "wss://relay.example.com/"],
+    ["title", "GM"]
+  ]
+}
+```
+
+Replies to kind `309` MUST use [NIP-73](https://github.com/nostr-protocol/nips/pull/1233)
+kind `1111` comments with a matching `~` tag. Clients SHOULD encourage flat reply
+hierarchies.
+
+# Membership
+
+Users MAY track and optionally advertise their own group memberships using a [NIP 51](51.md) kind `10209` event. Tags MAY be either public or encrypted with [NIP 44](44.md), depending on user/client preference.
+
+Room membership SHOULD be indicated using both an `r` tag for each relay the user is a member of, and a `~` tag for each room the user is a member of. `~` tags MUST include a relay url as the second argument.
+
+```json
+{
+  "kind": "10209",
+  "tags": [
+    ["r", "wss://relay.other.com/"],
+    ["~", "Good Morning", "wss://relay.other.com/"]
+  ],
+}
+```
+
+Room membership events SHOULD be sent to:
+
+- The user's [NIP-65](./65.md) WRITE relays
+- Each relay listed in the membership event
+- Each relay being removed from the member list
+
+# Federation
+
+Relays hosting rooms MAY indicate federation with other relays for rooms
+by publishing a `kind 30209` event using the key indicated by the relay's
+NIP 11 document.
+
+A relay may indicate partial federation using one or more `~` tags, or complete
+federation using a `r` tag.
+
+```json
+{
+  "kind": "30209",
+  "tags": [
+    ["r", "wss://other1.com"],
+    ["~", "Good Morning", "wss://other2.com/"],
+    ["~", "Good Morning", "wss://other3.com/"]
+  ],
+}
+```
+
+This can be useful if a conversation needs to be moved from one relay to another,
+or if multiple people want to host a conversation simultaneously.