diff --git a/CHANGELOG.md b/CHANGELOG.md
index faaf6a1..2e350b4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,6 +13,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Created API endpoint for adding aliases.
 - Populate `alsoKnownAs` property on actor object with declared aliases.
 - Support account migration from Mastodon.
+- Created API endpoint for managing client configurations.
 
 ### Changed
 
diff --git a/docs/openapi.yaml b/docs/openapi.yaml
index a9c432b..f092044 100644
--- a/docs/openapi.yaml
+++ b/docs/openapi.yaml
@@ -780,6 +780,29 @@ paths:
                 type: array
                 items:
                   $ref: '#/components/schemas/Notification'
+  /api/v1/settings/client_config:
+    post:
+      summary: Update client configuration.
+      security:
+        - tokenAuth: []
+      requestBody:
+        content:
+          application/json:
+            schema:
+              description: |
+                Client configuration.
+                Should contain a single key identifying type of client.
+              type: object
+              example: {"mitra-web":{"theme":"dark"}}
+      responses:
+        200:
+          description: Successful operation.
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/CredentialAccount'
+        400:
+          description: Invalid request data.
   /api/v1/settings/change_password:
     post:
       summary: Set or change user's password.
@@ -1504,6 +1527,10 @@ components:
             role:
               description: The role assigned to the currently authorized user.
               $ref: '#/components/schemas/Role'
+            client_config:
+              description: Client configurations.
+              type: object
+              example: {"mitra-web":{"theme":"dark"}}
     ActivityParameters:
       type: object
       properties:
diff --git a/mitra-models/migrations/V0053__user_account__client_config.sql b/mitra-models/migrations/V0053__user_account__client_config.sql
new file mode 100644
index 0000000..10b2a4b
--- /dev/null
+++ b/mitra-models/migrations/V0053__user_account__client_config.sql
@@ -0,0 +1 @@
+ALTER TABLE user_account ADD COLUMN client_config JSONB NOT NULL DEFAULT '{}';
diff --git a/mitra-models/migrations/schema.sql b/mitra-models/migrations/schema.sql
index e616573..9ce38e3 100644
--- a/mitra-models/migrations/schema.sql
+++ b/mitra-models/migrations/schema.sql
@@ -58,6 +58,7 @@ CREATE TABLE user_account (
     private_key TEXT NOT NULL,
     invite_code VARCHAR(100) UNIQUE REFERENCES user_invite_code (code) ON DELETE SET NULL,
     user_role SMALLINT NOT NULL,
+    client_config JSONB NOT NULL DEFAULT '{}',
     created_at TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT now()
 );
 
diff --git a/mitra-models/src/users/queries.rs b/mitra-models/src/users/queries.rs
index e5f1ad1..7099136 100644
--- a/mitra-models/src/users/queries.rs
+++ b/mitra-models/src/users/queries.rs
@@ -1,3 +1,4 @@
+use serde_json::{Value as JsonValue};
 use uuid::Uuid;
 
 use mitra_utils::{
@@ -17,6 +18,8 @@ use crate::profiles::{
 };
 
 use super::types::{
+    ClientConfig,
+    DbClientConfig,
     DbInviteCode,
     DbUser,
     Role,
@@ -189,6 +192,26 @@ pub async fn set_user_role(
     Ok(())
 }
 
+pub async fn update_client_config(
+    db_client: &impl DatabaseClient,
+    user_id: &Uuid,
+    client_name: &str,
+    client_config_value: &JsonValue,
+) -> Result<ClientConfig, DatabaseError> {
+    let maybe_row = db_client.query_opt(
+        "
+        UPDATE user_account
+        SET client_config = jsonb_set(client_config, ARRAY[$1], $2, true)
+        WHERE id = $3
+        RETURNING client_config
+        ",
+        &[&client_name, &client_config_value, &user_id],
+    ).await?;
+    let row = maybe_row.ok_or(DatabaseError::NotFound("user"))?;
+    let client_config: DbClientConfig = row.try_get("client_config")?;
+    Ok(client_config.into_inner())
+}
+
 pub async fn get_user_by_id(
     db_client: &impl DatabaseClient,
     user_id: &Uuid,
@@ -308,6 +331,7 @@ pub async fn get_user_count(
 
 #[cfg(test)]
 mod tests {
+    use serde_json::json;
     use serial_test::serial;
     use crate::database::test_utils::create_test_database;
     use crate::users::types::Role;
@@ -362,4 +386,25 @@ mod tests {
         let user = get_user_by_id(db_client, &user.id).await.unwrap();
         assert_eq!(user.role, Role::ReadOnlyUser);
     }
+
+    #[tokio::test]
+    #[serial]
+    async fn test_update_client_config() {
+        let db_client = &mut create_test_database().await;
+        let user_data = UserCreateData::default();
+        let user = create_user(db_client, user_data).await.unwrap();
+        assert_eq!(user.client_config.is_empty(), true);
+        let client_name = "test";
+        let client_config_value = json!({"a": 1});
+        let client_config = update_client_config(
+            db_client,
+            &user.id,
+            client_name,
+            &client_config_value,
+        ).await.unwrap();
+        assert_eq!(
+            client_config.get(client_name).unwrap(),
+            &client_config_value,
+        );
+    }
 }
diff --git a/mitra-models/src/users/types.rs b/mitra-models/src/users/types.rs
index 06d8bb2..d945c77 100644
--- a/mitra-models/src/users/types.rs
+++ b/mitra-models/src/users/types.rs
@@ -1,5 +1,9 @@
+use std::collections::HashMap;
+
 use chrono::{DateTime, Utc};
 use postgres_types::FromSql;
+use serde::Deserialize;
+use serde_json::{Value as JsonValue};
 use uuid::Uuid;
 
 use mitra_utils::{
@@ -9,6 +13,7 @@ use mitra_utils::{
 
 use crate::database::{
     int_enum::{int_enum_from_sql, int_enum_to_sql},
+    json_macro::json_from_sql,
     DatabaseTypeError,
 };
 use crate::profiles::types::DbActorProfile;
@@ -100,6 +105,20 @@ impl TryFrom<i16> for Role {
 int_enum_from_sql!(Role);
 int_enum_to_sql!(Role);
 
+pub type ClientConfig = HashMap<String, JsonValue>;
+
+#[derive(Deserialize)]
+pub struct DbClientConfig(ClientConfig);
+
+impl DbClientConfig {
+    pub fn into_inner(self) -> ClientConfig {
+        let Self(client_config) = self;
+        client_config
+    }
+}
+
+json_from_sql!(DbClientConfig);
+
 #[allow(dead_code)]
 #[derive(FromSql)]
 #[postgres(name = "user_account")]
@@ -110,6 +129,7 @@ pub struct DbUser {
     private_key: String,
     invite_code: Option<String>,
     user_role: Role,
+    client_config: DbClientConfig,
     created_at: DateTime<Utc>,
 }
 
@@ -122,6 +142,7 @@ pub struct User {
     pub password_hash: Option<String>,
     pub private_key: String,
     pub role: Role,
+    pub client_config: ClientConfig,
     pub profile: DbActorProfile,
 }
 
@@ -137,6 +158,7 @@ impl User {
             password_hash: db_user.password_hash,
             private_key: db_user.private_key,
             role: db_user.user_role,
+            client_config: db_user.client_config.into_inner(),
             profile: db_profile,
         }
     }
diff --git a/src/mastodon_api/accounts/types.rs b/src/mastodon_api/accounts/types.rs
index 977aea4..200bc41 100644
--- a/src/mastodon_api/accounts/types.rs
+++ b/src/mastodon_api/accounts/types.rs
@@ -14,8 +14,9 @@ use mitra_models::{
     },
     subscriptions::types::Subscription,
     users::types::{
-        Role,
+        ClientConfig,
         Permission,
+        Role,
         User,
     },
 };
@@ -126,6 +127,7 @@ pub struct Account {
     // CredentialAccount attributes
     pub source: Option<Source>,
     pub role: Option<ApiRole>,
+    pub client_config: Option<ClientConfig>,
 }
 
 impl Account {
@@ -220,6 +222,7 @@ impl Account {
             statuses_count: profile.post_count,
             source: None,
             role: None,
+            client_config: None,
         }
     }
 
@@ -248,6 +251,7 @@ impl Account {
         );
         account.source = Some(source);
         account.role = Some(role);
+        account.client_config = Some(user.client_config);
         account
     }
 }
diff --git a/src/mastodon_api/settings/views.rs b/src/mastodon_api/settings/views.rs
index 4595280..311151a 100644
--- a/src/mastodon_api/settings/views.rs
+++ b/src/mastodon_api/settings/views.rs
@@ -18,7 +18,11 @@ use mitra_models::{
         update_profile,
     },
     profiles::types::ProfileUpdateData,
-    users::queries::set_user_password,
+    users::queries::{
+        set_user_password,
+        update_client_config,
+    },
+    users::types::ClientConfig,
 };
 use mitra_utils::passwords::hash_password;
 
@@ -48,6 +52,37 @@ use super::types::{
     PasswordChangeRequest,
 };
 
+// Similar to Pleroma settings store
+// https://docs-develop.pleroma.social/backend/development/API/differences_in_mastoapi_responses/#pleroma-settings-store
+#[post("/client_config")]
+async fn client_config_view(
+    auth: BearerAuth,
+    connection_info: ConnectionInfo,
+    config: web::Data<Config>,
+    db_pool: web::Data<DbPool>,
+    request_data: web::Json<ClientConfig>,
+) -> Result<HttpResponse, MastodonError> {
+    let db_client = &**get_database_client(&db_pool).await?;
+    let mut current_user = get_current_user(db_client, auth.token()).await?;
+    if request_data.len() != 1 {
+        return Err(ValidationError("can't update more than one config").into());
+    };
+    let (client_name, client_config_value) =
+        request_data.iter().next().expect("hashmap entry should exist");
+    current_user.client_config = update_client_config(
+        db_client,
+        &current_user.id,
+        client_name,
+        client_config_value,
+    ).await?;
+    let account = Account::from_user(
+        &get_request_base_url(connection_info),
+        &config.instance_url(),
+        current_user,
+    );
+    Ok(HttpResponse::Ok().json(account))
+}
+
 #[post("/change_password")]
 async fn change_password_view(
     auth: BearerAuth,
@@ -231,6 +266,7 @@ async fn move_followers(
 
 pub fn settings_api_scope() -> Scope {
     web::scope("/api/v1/settings")
+        .service(client_config_view)
         .service(change_password_view)
         .service(add_alias_view)
         .service(export_followers_view)