diff --git a/src/service/rooms/metadata/mod.rs b/src/service/rooms/metadata/mod.rs
new file mode 100644
index 00000000..5d703451
--- /dev/null
+++ b/src/service/rooms/metadata/mod.rs
@@ -0,0 +1,44 @@
+    /// Checks if a room exists.
+    #[tracing::instrument(skip(self))]
+    pub fn exists(&self, room_id: &RoomId) -> Result<bool> {
+        let prefix = match self.get_shortroomid(room_id)? {
+            Some(b) => b.to_be_bytes().to_vec(),
+            None => return Ok(false),
+        };
+
+        // Look for PDUs in that room.
+        Ok(self
+            .pduid_pdu
+            .iter_from(&prefix, false)
+            .next()
+            .filter(|(k, _)| k.starts_with(&prefix))
+            .is_some())
+    }
+
+    pub fn get_shortroomid(&self, room_id: &RoomId) -> Result<Option<u64>> {
+        self.roomid_shortroomid
+            .get(room_id.as_bytes())?
+            .map(|bytes| {
+                utils::u64_from_bytes(&bytes)
+                    .map_err(|_| Error::bad_database("Invalid shortroomid in db."))
+            })
+            .transpose()
+    }
+
+    pub fn get_or_create_shortroomid(
+        &self,
+        room_id: &RoomId,
+        globals: &super::globals::Globals,
+    ) -> Result<u64> {
+        Ok(match self.roomid_shortroomid.get(room_id.as_bytes())? {
+            Some(short) => utils::u64_from_bytes(&short)
+                .map_err(|_| Error::bad_database("Invalid shortroomid in db."))?,
+            None => {
+                let short = globals.next_count()?;
+                self.roomid_shortroomid
+                    .insert(room_id.as_bytes(), &short.to_be_bytes())?;
+                short
+            }
+        })
+    }
+