diff --git a/ruma-client-api/src/r0/capabilities/get_capabilities.rs b/ruma-client-api/src/r0/capabilities/get_capabilities.rs
index 0b04d48d..4efcaa1c 100644
--- a/ruma-client-api/src/r0/capabilities/get_capabilities.rs
+++ b/ruma-client-api/src/r0/capabilities/get_capabilities.rs
@@ -1,12 +1,15 @@
 //! [GET /_matrix/client/r0/capabilities](https://matrix.org/docs/spec/client_server/r0.6.1#get-matrix-client-r0-capabilities)
 
+use std::{borrow::Cow, collections::BTreeMap};
+
 use maplit::btreemap;
 use ruma_api::ruma_api;
 use ruma_identifiers::RoomVersionId;
 use ruma_serde::StringEnum;
 use serde::{Deserialize, Serialize};
-use serde_json::Value as JsonValue;
-use std::collections::BTreeMap;
+use serde_json::{
+    from_value as from_json_value, to_value as to_json_value, Error, Value as JsonValue,
+};
 
 ruma_api! {
     metadata: {
@@ -72,7 +75,7 @@ pub struct Capabilities {
     /// Any other custom capabilities that the server supports outside of the specification,
     /// labeled using the Java package naming convention and stored as arbitrary JSON values.
     #[serde(flatten)]
-    pub custom_capabilities: BTreeMap<String, JsonValue>,
+    custom_capabilities: BTreeMap<String, JsonValue>,
 }
 
 impl Capabilities {
@@ -80,6 +83,31 @@ impl Capabilities {
     pub fn new() -> Self {
         Default::default()
     }
+
+    /// Returns value of the given capability.
+    pub fn get(&self, capability: &str) -> Result<Option<Cow<'_, JsonValue>>, Error> {
+        let value = match capability {
+            "m.change_password" => Some(Cow::Owned(to_json_value(&self.change_password)?)),
+            "m.room_versions" => Some(Cow::Owned(to_json_value(&self.room_versions)?)),
+            _ => match self.custom_capabilities.get(capability) {
+                Some(value) => Some(Cow::Borrowed(value)),
+                None => None,
+            },
+        };
+        Ok(value)
+    }
+
+    /// Sets the given value to a capability.
+    pub fn set(&mut self, capability_label: &str, capability: JsonValue) -> Result<(), Error> {
+        match capability_label {
+            "m.change_password" => self.change_password = from_json_value(capability)?,
+            "m.room_versions" => self.room_versions = from_json_value(capability)?,
+            _ => {
+                self.custom_capabilities.insert(capability_label.to_owned(), capability);
+            }
+        }
+        Ok(())
+    }
 }
 
 /// Information about the m.change_password capability