diff --git a/ruma-common/CHANGELOG.md b/ruma-common/CHANGELOG.md
index 3d791ffe..46144eba 100644
--- a/ruma-common/CHANGELOG.md
+++ b/ruma-common/CHANGELOG.md
@@ -7,6 +7,8 @@ Breaking changes:
 Improvements:
 
 * Add the `thirdparty` module
+* Add `directory::{Filter, PublicRoomsChunk, RoomNetwork}` (moved from
+  `ruma_client_api::r0::directory`)
 
 # 0.2.0
 
diff --git a/ruma-common/src/directory.rs b/ruma-common/src/directory.rs
new file mode 100644
index 00000000..eb723a8b
--- /dev/null
+++ b/ruma-common/src/directory.rs
@@ -0,0 +1,224 @@
+//! Common types for room directory endpoints
+
+use std::fmt;
+
+use js_int::UInt;
+use ruma_identifiers::{RoomAliasId, RoomId};
+use serde::{
+    de::{Error, MapAccess, Visitor},
+    ser::SerializeStruct,
+    Deserialize, Deserializer, Serialize, Serializer,
+};
+
+use serde_json::Value as JsonValue;
+
+/// A chunk of a room list response, describing one room
+#[derive(Clone, Debug, Deserialize, Serialize)]
+pub struct PublicRoomsChunk {
+    /// Aliases of the room.
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub aliases: Vec<RoomAliasId>,
+
+    /// The canonical alias of the room, if any.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub canonical_alias: Option<RoomAliasId>,
+
+    /// The name of the room, if any.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub name: Option<String>,
+
+    /// The number of members joined to the room.
+    pub num_joined_members: UInt,
+
+    /// The ID of the room.
+    pub room_id: RoomId,
+
+    /// The topic of the room, if any.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub topic: Option<String>,
+
+    /// Whether the room may be viewed by guest users without joining.
+    pub world_readable: bool,
+
+    /// Whether guest users may join the room and participate in it.
+    ///
+    /// If they can, they will be subject to ordinary power level rules like any other user.
+    pub guest_can_join: bool,
+
+    /// The URL for the room's avatar, if one is set.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub avatar_url: Option<String>,
+}
+
+/// A filter for public rooms lists
+#[derive(Clone, Debug, Deserialize, Serialize)]
+pub struct Filter {
+    /// A string to search for in the room metadata, e.g. name, topic, canonical alias etc.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub generic_search_term: Option<String>,
+}
+
+/// Information about which networks/protocols from application services on the
+/// homeserver from which to request rooms.
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub enum RoomNetwork {
+    /// Return rooms from the Matrix network.
+    Matrix,
+
+    /// Return rooms from all the networks/protocols the homeserver knows about.
+    All,
+
+    /// Return rooms from a specific third party network/protocol.
+    ThirdParty(String),
+}
+
+impl Default for RoomNetwork {
+    fn default() -> Self {
+        RoomNetwork::Matrix
+    }
+}
+
+impl Serialize for RoomNetwork {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        let mut state;
+        match self {
+            Self::Matrix => {
+                state = serializer.serialize_struct("RoomNetwork", 0)?;
+            }
+            Self::All => {
+                state = serializer.serialize_struct("RoomNetwork", 1)?;
+                state.serialize_field("include_all_networks", &true)?;
+            }
+            Self::ThirdParty(network) => {
+                state = serializer.serialize_struct("RoomNetwork", 1)?;
+                state.serialize_field("third_party_instance_id", network)?;
+            }
+        }
+        state.end()
+    }
+}
+
+impl<'de> Deserialize<'de> for RoomNetwork {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        deserializer.deserialize_map(RoomNetworkVisitor)
+    }
+}
+
+struct RoomNetworkVisitor;
+impl<'de> Visitor<'de> for RoomNetworkVisitor {
+    type Value = RoomNetwork;
+
+    fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        formatter.write_str("Network selection")
+    }
+
+    fn visit_map<M>(self, mut access: M) -> Result<Self::Value, M::Error>
+    where
+        M: MapAccess<'de>,
+    {
+        let mut include_all_networks = false;
+        let mut third_party_instance_id = None;
+        while let Some((key, value)) = access.next_entry::<String, JsonValue>()? {
+            match key.as_str() {
+                "include_all_networks" => {
+                    include_all_networks = match value.as_bool() {
+                        Some(b) => b,
+                        _ => false,
+                    }
+                }
+                "third_party_instance_id" => {
+                    third_party_instance_id = value.as_str().map(|v| v.to_owned())
+                }
+                _ => {}
+            };
+        }
+
+        if include_all_networks {
+            if third_party_instance_id.is_none() {
+                Ok(RoomNetwork::All)
+            } else {
+                Err(M::Error::custom(
+                    "`include_all_networks = true` and `third_party_instance_id` are mutually exclusive.",
+                ))
+            }
+        } else {
+            Ok(match third_party_instance_id {
+                Some(network) => RoomNetwork::ThirdParty(network),
+                None => RoomNetwork::Matrix,
+            })
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use serde_json::{from_value as from_json_value, json, to_value as to_json_value};
+
+    use super::RoomNetwork;
+
+    #[test]
+    fn test_serialize_matrix_network_only() {
+        let json = json!({});
+        assert_eq!(to_json_value(RoomNetwork::Matrix).unwrap(), json);
+    }
+
+    #[test]
+    fn test_deserialize_matrix_network_only() {
+        let json = json!({ "include_all_networks": false });
+        assert_eq!(from_json_value::<RoomNetwork>(json).unwrap(), RoomNetwork::Matrix);
+    }
+
+    #[test]
+    fn test_serialize_default_network_is_empty() {
+        let json = json!({});
+        assert_eq!(to_json_value(RoomNetwork::default()).unwrap(), json);
+    }
+
+    #[test]
+    fn test_deserialize_empty_network_is_default() {
+        let json = json!({});
+        assert_eq!(from_json_value::<RoomNetwork>(json).unwrap(), RoomNetwork::default());
+    }
+
+    #[test]
+    fn test_serialize_include_all_networks() {
+        let json = json!({ "include_all_networks": true });
+        assert_eq!(to_json_value(RoomNetwork::All).unwrap(), json);
+    }
+
+    #[test]
+    fn test_deserialize_include_all_networks() {
+        let json = json!({ "include_all_networks": true });
+        assert_eq!(from_json_value::<RoomNetwork>(json).unwrap(), RoomNetwork::All);
+    }
+
+    #[test]
+    fn test_serialize_third_party_network() {
+        let json = json!({ "third_party_instance_id": "freenode" });
+        assert_eq!(to_json_value(RoomNetwork::ThirdParty("freenode".into())).unwrap(), json);
+    }
+
+    #[test]
+    fn test_deserialize_third_party_network() {
+        let json = json!({ "third_party_instance_id": "freenode" });
+        assert_eq!(
+            from_json_value::<RoomNetwork>(json).unwrap(),
+            RoomNetwork::ThirdParty("freenode".into())
+        );
+    }
+
+    #[test]
+    fn test_deserialize_include_all_networks_and_third_party_exclusivity() {
+        let json = json!({ "include_all_networks": true, "third_party_instance_id": "freenode" });
+        assert_eq!(
+            from_json_value::<RoomNetwork>(json).unwrap_err().to_string().as_str(),
+            "`include_all_networks = true` and `third_party_instance_id` are mutually exclusive."
+        );
+    }
+}
diff --git a/ruma-common/src/lib.rs b/ruma-common/src/lib.rs
index a4faa72f..049c44c2 100644
--- a/ruma-common/src/lib.rs
+++ b/ruma-common/src/lib.rs
@@ -2,6 +2,7 @@
 
 #![warn(missing_docs, missing_debug_implementations)]
 
+pub mod directory;
 pub mod encryption;
 pub mod presence;
 pub mod push;