diff --git a/Cargo.lock b/Cargo.lock
index 6d39eca..5cf99b1 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -213,6 +213,7 @@ dependencies = [
  "serde",
  "serde_json",
  "smallvec",
+ "smartstring",
  "strum",
  "strum_macros",
  "teloxide",
@@ -1826,6 +1827,18 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "smartstring"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3fb72c633efbaa2dd666986505016c32c3044395ceaf881518399d2f4127ee29"
+dependencies = [
+ "autocfg",
+ "serde",
+ "static_assertions",
+ "version_check",
+]
+
 [[package]]
 name = "smawk"
 version = "0.3.1"
diff --git a/Cargo.toml b/Cargo.toml
index 5752c25..72acd21 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -29,3 +29,4 @@ lazy_static = "1.4.0"
 moka = { version = "0.11.1", features = ["future"] }
 axum = "0.6.18"
 smallvec = { version = "1.10.0", features = ["serde"] }
+smartstring = { version = "1.0.1", features = ["serde"] }
diff --git a/src/bots/approved_bot/mod.rs b/src/bots/approved_bot/mod.rs
index 597ae3a..95ce285 100644
--- a/src/bots/approved_bot/mod.rs
+++ b/src/bots/approved_bot/mod.rs
@@ -2,6 +2,8 @@ pub mod modules;
 pub mod services;
 mod tools;
 
+use smartstring::alias::String as SmartString;
+
 use moka::future::Cache;
 use smallvec::SmallVec;
 use teloxide::{prelude::*, types::BotCommand, adaptors::{Throttle, CacheMe}};
@@ -24,7 +26,7 @@ async fn _update_activity(
     me: teloxide::types::Me,
     user: teloxide::types::User,
     activity_cache: Cache<UserId, ()>,
-    user_langs_cache: Cache<UserId, SmallVec<[String; 3]>>,
+    user_langs_cache: Cache<UserId, SmallVec<[SmartString; 3]>>,
 ) -> Option<()> {
     if activity_cache.contains_key(&user.id) {
         return None;
diff --git a/src/bots/approved_bot/modules/book.rs b/src/bots/approved_bot/modules/book.rs
index 2fcd928..acf1ac8 100644
--- a/src/bots/approved_bot/modules/book.rs
+++ b/src/bots/approved_bot/modules/book.rs
@@ -1,6 +1,8 @@
 use core::fmt::Debug;
 use std::str::FromStr;
 
+use smartstring::alias::String as SmartString;
+
 use moka::future::Cache;
 use regex::Regex;
 use smallvec::SmallVec;
@@ -119,8 +121,8 @@ async fn send_book_handler<T, P, Fut>(
     message: Message,
     bot: CacheMe<Throttle<Bot>>,
     command: BookCommand,
-    books_getter: fn(id: u32, page: u32, allowed_langs: SmallVec<[String; 3]>) -> Fut,
-    user_langs_cache: Cache<UserId, SmallVec<[String; 3]>>,
+    books_getter: fn(id: u32, page: u32, allowed_langs: SmallVec<[SmartString; 3]>) -> Fut,
+    user_langs_cache: Cache<UserId, SmallVec<[SmartString; 3]>>,
 ) -> crate::bots::BotHandlerInternal
 where
     T: Format + Clone + Debug,
@@ -191,8 +193,8 @@ async fn send_pagination_book_handler<T, P, Fut>(
     cq: CallbackQuery,
     bot: CacheMe<Throttle<Bot>>,
     callback_data: BookCallbackData,
-    books_getter: fn(id: u32, page: u32, allowed_langs: SmallVec<[String; 3]>) -> Fut,
-    user_langs_cache: Cache<UserId, SmallVec<[String; 3]>>,
+    books_getter: fn(id: u32, page: u32, allowed_langs: SmallVec<[SmartString; 3]>) -> Fut,
+    user_langs_cache: Cache<UserId, SmallVec<[SmartString; 3]>>,
 ) -> crate::bots::BotHandlerInternal
 where
     T: Format + Clone + Debug,
diff --git a/src/bots/approved_bot/modules/download.rs b/src/bots/approved_bot/modules/download.rs
index f3e2bc1..e230420 100644
--- a/src/bots/approved_bot/modules/download.rs
+++ b/src/bots/approved_bot/modules/download.rs
@@ -438,7 +438,7 @@ async fn download_archive(
         object_id: id,
         object_type: task_type,
         file_format: file_type,
-        allowed_langs: allowed_langs.into_vec(),
+        allowed_langs,
     }).await;
 
     let mut task = match task {
diff --git a/src/bots/approved_bot/modules/random.rs b/src/bots/approved_bot/modules/random.rs
index d808314..fa33f3f 100644
--- a/src/bots/approved_bot/modules/random.rs
+++ b/src/bots/approved_bot/modules/random.rs
@@ -1,4 +1,5 @@
 use moka::future::Cache;
+use smartstring::alias::String as SmartString;
 use smallvec::SmallVec;
 use strum_macros::{Display, EnumIter};
 use teloxide::{
@@ -169,8 +170,8 @@ where
 async fn get_random_item_handler<T, Fut>(
     cq: CallbackQuery,
     bot: CacheMe<Throttle<Bot>>,
-    item_getter: fn(allowed_langs: SmallVec<[String; 3]>) -> Fut,
-    user_langs_cache: Cache<UserId, SmallVec<[String; 3]>>,
+    item_getter: fn(allowed_langs: SmallVec<[SmartString; 3]>) -> Fut,
+    user_langs_cache: Cache<UserId, SmallVec<[SmartString; 3]>>,
 ) -> BotHandlerInternal
 where
     T: Format,
@@ -243,7 +244,7 @@ async fn get_genres_by_meta_handler(
         }
     };
 
-    let mut buttons: Vec<Vec<InlineKeyboardButton>> = book_library::get_genres(meta.to_string()).await?
+    let mut buttons: Vec<Vec<InlineKeyboardButton>> = book_library::get_genres(meta.into()).await?
         .items
         .into_iter()
         .map(|genre| {
@@ -294,7 +295,7 @@ async fn get_random_book_by_genre(
     cq: CallbackQuery,
     bot: CacheMe<Throttle<Bot>>,
     genre_id: u32,
-    user_langs_cache: Cache<UserId, SmallVec<[String; 3]>>,
+    user_langs_cache: Cache<UserId, SmallVec<[SmartString; 3]>>,
 ) -> BotHandlerInternal {
     let allowed_langs = get_user_or_default_lang_codes(cq.from.id, user_langs_cache).await;
 
diff --git a/src/bots/approved_bot/modules/search.rs b/src/bots/approved_bot/modules/search.rs
index 9d873cc..3def819 100644
--- a/src/bots/approved_bot/modules/search.rs
+++ b/src/bots/approved_bot/modules/search.rs
@@ -1,6 +1,8 @@
 use core::fmt::Debug;
 use std::str::FromStr;
 
+use smartstring::alias::String as SmartString;
+
 use moka::future::Cache;
 use regex::Regex;
 use smallvec::SmallVec;
@@ -112,8 +114,8 @@ async fn generic_search_pagination_handler<T, P, Fut>(
     cq: CallbackQuery,
     bot: CacheMe<Throttle<Bot>>,
     search_data: SearchCallbackData,
-    items_getter: fn(query: String, page: u32, allowed_langs: SmallVec<[String; 3]>) -> Fut,
-    user_langs_cache: Cache<UserId, SmallVec<[String; 3]>>,
+    items_getter: fn(query: String, page: u32, allowed_langs: SmallVec<[SmartString; 3]>) -> Fut,
+    user_langs_cache: Cache<UserId, SmallVec<[SmartString; 3]>>,
 ) -> BotHandlerInternal
 where
     T: Format + Clone + Debug,
diff --git a/src/bots/approved_bot/modules/settings.rs b/src/bots/approved_bot/modules/settings.rs
index 2cebe5c..65d31a2 100644
--- a/src/bots/approved_bot/modules/settings.rs
+++ b/src/bots/approved_bot/modules/settings.rs
@@ -1,4 +1,6 @@
-use std::{collections::HashSet, str::FromStr, vec};
+use std::{collections::HashSet, str::FromStr};
+
+use smartstring::alias::String as SmartString;
 
 use crate::{bots::{
     approved_bot::{
@@ -28,8 +30,8 @@ enum SettingsCommand {
 #[derive(Clone)]
 enum SettingsCallbackData {
     Settings,
-    On { code: String },
-    Off { code: String },
+    On { code: SmartString },
+    Off { code: SmartString },
 }
 
 impl FromStr for SettingsCallbackData {
@@ -52,8 +54,8 @@ impl FromStr for SettingsCallbackData {
         let code = caps["code"].to_string();
 
         match action {
-            "on" => Ok(SettingsCallbackData::On { code }),
-            "off" => Ok(SettingsCallbackData::Off { code }),
+            "on" => Ok(SettingsCallbackData::On { code: code.into() }),
+            "off" => Ok(SettingsCallbackData::Off { code: code.into() }),
             _ => Err(strum::ParseError::VariantNotFound),
         }
     }
@@ -88,7 +90,7 @@ async fn settings_handler(message: Message, bot: CacheMe<Throttle<Bot>>) -> BotH
     Ok(())
 }
 
-fn get_lang_keyboard(all_langs: Vec<Lang>, allowed_langs: HashSet<String>) -> InlineKeyboardMarkup {
+fn get_lang_keyboard(all_langs: Vec<Lang>, allowed_langs: HashSet<SmartString>) -> InlineKeyboardMarkup {
     let buttons = all_langs
         .into_iter()
         .map(|lang| {
@@ -120,7 +122,7 @@ async fn settings_callback_handler(
     bot: CacheMe<Throttle<Bot>>,
     callback_data: SettingsCallbackData,
     me: Me,
-    user_langs_cache: Cache<UserId, SmallVec<[String; 3]>>,
+    user_langs_cache: Cache<UserId, SmallVec<[SmartString; 3]>>,
 ) -> BotHandlerInternal {
     let message = match cq.message {
         Some(v) => v,
@@ -134,7 +136,7 @@ async fn settings_callback_handler(
 
     let allowed_langs = get_user_or_default_lang_codes(user.id, user_langs_cache.clone()).await;
 
-    let mut allowed_langs_set: HashSet<String> = HashSet::new();
+    let mut allowed_langs_set: HashSet<SmartString> = HashSet::new();
     allowed_langs.into_iter().for_each(|v| {
         allowed_langs_set.insert(v);
     });
diff --git a/src/bots/approved_bot/modules/update_history.rs b/src/bots/approved_bot/modules/update_history.rs
index afd9a1f..2658881 100644
--- a/src/bots/approved_bot/modules/update_history.rs
+++ b/src/bots/approved_bot/modules/update_history.rs
@@ -152,8 +152,8 @@ async fn update_log_pagination_handler(
 
     let mut items_page = get_uploaded_books(
         update_callback_data.page,
-        update_callback_data.from.format("%Y-%m-%d").to_string(),
-        update_callback_data.to.format("%Y-%m-%d").to_string(),
+        update_callback_data.from.format("%Y-%m-%d").to_string().into(),
+        update_callback_data.to.format("%Y-%m-%d").to_string().into(),
     )
     .await?;
 
@@ -168,8 +168,8 @@ async fn update_log_pagination_handler(
     if update_callback_data.page > items_page.pages {
         items_page = get_uploaded_books(
             items_page.pages,
-            update_callback_data.from.format("%Y-%m-%d").to_string(),
-            update_callback_data.to.format("%Y-%m-%d").to_string(),
+            update_callback_data.from.format("%Y-%m-%d").to_string().into(),
+            update_callback_data.to.format("%Y-%m-%d").to_string().into(),
         ).await?;
     }
 
diff --git a/src/bots/approved_bot/services/batch_downloader.rs b/src/bots/approved_bot/services/batch_downloader.rs
index 9541918..9e75481 100644
--- a/src/bots/approved_bot/services/batch_downloader.rs
+++ b/src/bots/approved_bot/services/batch_downloader.rs
@@ -1,3 +1,6 @@
+use smallvec::SmallVec;
+use smartstring::alias::String as SmartString;
+
 use serde::{Deserialize, Serialize};
 
 use crate::config;
@@ -23,7 +26,7 @@ pub struct CreateTaskData {
     pub object_id: u32,
     pub object_type: TaskObjectType,
     pub file_format: String,
-    pub allowed_langs: Vec<String>,
+    pub allowed_langs: SmallVec<[SmartString; 3]>,
 }
 
 #[derive(Deserialize)]
diff --git a/src/bots/approved_bot/services/book_library/mod.rs b/src/bots/approved_bot/services/book_library/mod.rs
index fb6c2f0..fb69dbd 100644
--- a/src/bots/approved_bot/services/book_library/mod.rs
+++ b/src/bots/approved_bot/services/book_library/mod.rs
@@ -1,6 +1,8 @@
 pub mod formaters;
 pub mod types;
 
+use smartstring::alias::String as SmartString;
+
 use serde::de::DeserializeOwned;
 use smallvec::SmallVec;
 
@@ -8,7 +10,7 @@ use crate::config;
 
 use self::types::Empty;
 
-fn get_allowed_langs_params(allowed_langs: SmallVec<[String; 3]>) -> Vec<(&'static str, String)> {
+fn get_allowed_langs_params(allowed_langs: SmallVec<[SmartString; 3]>) -> Vec<(&'static str, SmartString)> {
     allowed_langs
         .into_iter()
         .map(|lang| ("allowed_langs", lang))
@@ -17,7 +19,7 @@ fn get_allowed_langs_params(allowed_langs: SmallVec<[String; 3]>) -> Vec<(&'stat
 
 async fn _make_request<T>(
     url: &str,
-    params: Vec<(&str, String)>,
+    params: Vec<(&str, SmartString)>,
 ) -> Result<T, Box<dyn std::error::Error + Send + Sync>>
 where
     T: DeserializeOwned,
@@ -46,34 +48,34 @@ pub async fn get_book(
 }
 
 pub async fn get_random_book_by_genre(
-    allowed_langs: SmallVec<[String; 3]>,
+    allowed_langs: SmallVec<[SmartString; 3]>,
     genre: Option<u32>,
 ) -> Result<types::Book, Box<dyn std::error::Error + Send + Sync>> {
-    let mut params: Vec<(&str, String)> = get_allowed_langs_params(allowed_langs);
+    let mut params = get_allowed_langs_params(allowed_langs);
 
     if let Some(v) = genre {
-        params.push(("genre", v.to_string()));
+        params.push(("genre", v.to_string().into()));
     }
 
     _make_request("/api/v1/books/random", params).await
 }
 
 pub async fn get_random_book(
-    allowed_langs: SmallVec<[String; 3]>,
+    allowed_langs: SmallVec<[SmartString; 3]>,
 ) -> Result<types::Book, Box<dyn std::error::Error + Send + Sync>> {
     get_random_book_by_genre(allowed_langs, None).await
 }
 
 pub async fn get_random_author(
-    allowed_langs: SmallVec<[String; 3]>,
+    allowed_langs: SmallVec<[SmartString; 3]>,
 ) -> Result<types::Author, Box<dyn std::error::Error + Send + Sync>> {
-    let params: Vec<(&str, String)> = get_allowed_langs_params(allowed_langs);
+    let params = get_allowed_langs_params(allowed_langs);
 
     _make_request("/api/v1/authors/random", params).await
 }
 
 pub async fn get_random_sequence(
-    allowed_langs: SmallVec<[String; 3]>,
+    allowed_langs: SmallVec<[SmartString; 3]>,
 ) -> Result<types::Sequence, Box<dyn std::error::Error + Send + Sync>> {
     let params = get_allowed_langs_params(allowed_langs);
 
@@ -85,7 +87,7 @@ pub async fn get_genre_metas() -> Result<Vec<String>, Box<dyn std::error::Error
 }
 
 pub async fn get_genres(
-    meta: String,
+    meta: SmartString,
 ) -> Result<types::Page<types::Genre, Empty>, Box<dyn std::error::Error + Send + Sync>> {
     let params = vec![("meta", meta)];
 
@@ -97,12 +99,12 @@ const PAGE_SIZE: &str = "5";
 pub async fn search_book(
     query: String,
     page: u32,
-    allowed_langs: SmallVec<[String; 3]>,
+    allowed_langs: SmallVec<[SmartString; 3]>,
 ) -> Result<types::Page<types::SearchBook, Empty>, Box<dyn std::error::Error + Send + Sync>> {
     let mut params = get_allowed_langs_params(allowed_langs);
 
-    params.push(("page", page.to_string()));
-    params.push(("size", PAGE_SIZE.to_string()));
+    params.push(("page", page.to_string().into()));
+    params.push(("size", PAGE_SIZE.to_string().into()));
 
     _make_request(format!("/api/v1/books/search/{query}").as_str(), params).await
 }
@@ -110,12 +112,12 @@ pub async fn search_book(
 pub async fn search_author(
     query: String,
     page: u32,
-    allowed_langs: SmallVec<[String; 3]>,
+    allowed_langs: SmallVec<[SmartString; 3]>,
 ) -> Result<types::Page<types::Author, Empty>, Box<dyn std::error::Error + Send + Sync>> {
     let mut params = get_allowed_langs_params(allowed_langs);
 
-    params.push(("page", page.to_string()));
-    params.push(("size", PAGE_SIZE.to_string()));
+    params.push(("page", page.to_string().into()));
+    params.push(("size", PAGE_SIZE.to_string().into()));
 
     _make_request(format!("/api/v1/authors/search/{query}").as_str(), params).await
 }
@@ -123,12 +125,12 @@ pub async fn search_author(
 pub async fn search_sequence(
     query: String,
     page: u32,
-    allowed_langs: SmallVec<[String; 3]>,
+    allowed_langs: SmallVec<[SmartString; 3]>,
 ) -> Result<types::Page<types::Sequence, Empty>, Box<dyn std::error::Error + Send + Sync>> {
     let mut params = get_allowed_langs_params(allowed_langs);
 
-    params.push(("page", page.to_string()));
-    params.push(("size", PAGE_SIZE.to_string()));
+    params.push(("page", page.to_string().into()));
+    params.push(("size", PAGE_SIZE.to_string().into()));
 
     _make_request(format!("/api/v1/sequences/search/{query}").as_str(), params).await
 }
@@ -136,12 +138,12 @@ pub async fn search_sequence(
 pub async fn search_translator(
     query: String,
     page: u32,
-    allowed_langs: SmallVec<[String; 3]>,
+    allowed_langs: SmallVec<[SmartString; 3]>,
 ) -> Result<types::Page<types::Translator, Empty>, Box<dyn std::error::Error + Send + Sync>> {
     let mut params = get_allowed_langs_params(allowed_langs);
 
-    params.push(("page", page.to_string()));
-    params.push(("size", PAGE_SIZE.to_string()));
+    params.push(("page", page.to_string().into()));
+    params.push(("size", PAGE_SIZE.to_string().into()));
 
     _make_request(
         format!("/api/v1/translators/search/{query}").as_str(),
@@ -165,12 +167,12 @@ pub async fn get_author_annotation(
 pub async fn get_author_books(
     id: u32,
     page: u32,
-    allowed_langs: SmallVec<[String; 3]>,
+    allowed_langs: SmallVec<[SmartString; 3]>,
 ) -> Result<types::Page<types::AuthorBook, types::BookAuthor>, Box<dyn std::error::Error + Send + Sync>> {
     let mut params = get_allowed_langs_params(allowed_langs);
 
-    params.push(("page", page.to_string()));
-    params.push(("size", PAGE_SIZE.to_string()));
+    params.push(("page", page.to_string().into()));
+    params.push(("size", PAGE_SIZE.to_string().into()));
 
     _make_request(format!("/api/v1/authors/{id}/books").as_str(), params).await
 }
@@ -178,12 +180,12 @@ pub async fn get_author_books(
 pub async fn get_translator_books(
     id: u32,
     page: u32,
-    allowed_langs: SmallVec<[String; 3]>,
+    allowed_langs: SmallVec<[SmartString; 3]>,
 ) -> Result<types::Page<types::TranslatorBook, types::BookTranslator>, Box<dyn std::error::Error + Send + Sync>> {
     let mut params = get_allowed_langs_params(allowed_langs);
 
-    params.push(("page", page.to_string()));
-    params.push(("size", PAGE_SIZE.to_string()));
+    params.push(("page", page.to_string().into()));
+    params.push(("size", PAGE_SIZE.to_string().into()));
 
     _make_request(format!("/api/v1/translators/{id}/books").as_str(), params).await
 }
@@ -191,27 +193,27 @@ pub async fn get_translator_books(
 pub async fn get_sequence_books(
     id: u32,
     page: u32,
-    allowed_langs: SmallVec<[String; 3]>,
+    allowed_langs: SmallVec<[SmartString; 3]>,
 ) -> Result<types::Page<types::SequenceBook, types::Sequence>, Box<dyn std::error::Error + Send + Sync>> {
     let mut params = get_allowed_langs_params(allowed_langs);
 
-    params.push(("page", page.to_string()));
-    params.push(("size", PAGE_SIZE.to_string()));
+    params.push(("page", page.to_string().into()));
+    params.push(("size", PAGE_SIZE.to_string().into()));
 
     _make_request(format!("/api/v1/sequences/{id}/books").as_str(), params).await
 }
 
 pub async fn get_uploaded_books(
     page: u32,
-    uploaded_gte: String,
-    uploaded_lte: String,
+    uploaded_gte: SmartString,
+    uploaded_lte: SmartString,
 ) -> Result<types::Page<types::SearchBook, Empty>, Box<dyn std::error::Error + Send + Sync>> {
     let params = vec![
-        ("page", page.to_string()),
-        ("size", PAGE_SIZE.to_string()),
+        ("page", page.to_string().into()),
+        ("size", PAGE_SIZE.to_string().into()),
         ("uploaded_gte", uploaded_gte),
         ("uploaded_lte", uploaded_lte),
-        ("is_deleted", "false".to_string()),
+        ("is_deleted", "false".into()),
     ];
 
     _make_request("/api/v1/books/", params).await
@@ -219,7 +221,7 @@ pub async fn get_uploaded_books(
 
 pub async fn get_author_books_available_types(
     id: u32,
-    allowed_langs: SmallVec<[String; 3]>,
+    allowed_langs: SmallVec<[SmartString; 3]>,
 ) -> Result<Vec<String>, Box<dyn std::error::Error + Send + Sync>> {
     let params = get_allowed_langs_params(allowed_langs);
 
@@ -228,7 +230,7 @@ pub async fn get_author_books_available_types(
 
 pub async fn get_translator_books_available_types(
     id: u32,
-    allowed_langs: SmallVec<[String; 3]>,
+    allowed_langs: SmallVec<[SmartString; 3]>,
 ) -> Result<Vec<String>, Box<dyn std::error::Error + Send + Sync>> {
     let params = get_allowed_langs_params(allowed_langs);
 
@@ -237,7 +239,7 @@ pub async fn get_translator_books_available_types(
 
 pub async fn get_sequence_books_available_types(
     id: u32,
-    allowed_langs: SmallVec<[String; 3]>
+    allowed_langs: SmallVec<[SmartString; 3]>
 ) -> Result<Vec<String>, Box<dyn std::error::Error + Send + Sync>> {
     let params = get_allowed_langs_params(allowed_langs);
 
diff --git a/src/bots/approved_bot/services/user_settings/mod.rs b/src/bots/approved_bot/services/user_settings/mod.rs
index ea52576..e60d7bb 100644
--- a/src/bots/approved_bot/services/user_settings/mod.rs
+++ b/src/bots/approved_bot/services/user_settings/mod.rs
@@ -2,24 +2,25 @@ use moka::future::Cache;
 use serde::Deserialize;
 use serde_json::json;
 use smallvec::{SmallVec, smallvec};
-use teloxide::{types::{UserId, ChatId}};
+use teloxide::types::{UserId, ChatId};
+use smartstring::alias::String as SmartString;
 
 use crate::config;
 
 #[derive(Deserialize, Debug, Clone)]
 pub struct Lang {
     // pub id: u32,
-    pub label: String,
-    pub code: String,
+    pub label: SmartString,
+    pub code: SmartString,
 }
 
 #[derive(Deserialize, Debug, Clone)]
 pub struct UserSettings {
     pub user_id: u64,
-    pub last_name: String,
-    pub first_name: String,
-    pub username: String,
-    pub source: String,
+    pub last_name: SmartString,
+    pub first_name: SmartString,
+    pub username: SmartString,
+    pub source: SmartString,
     pub allowed_langs: SmallVec<[Lang; 3]>,
 }
 
@@ -42,17 +43,21 @@ pub async fn get_user_settings(
 
 pub async fn get_user_or_default_lang_codes(
     user_id: UserId,
-    cache: Cache<UserId, SmallVec<[String; 3]>>
-) -> SmallVec<[String; 3]> {
+    cache: Cache<UserId, SmallVec<[SmartString; 3]>>
+) -> SmallVec<[SmartString; 3]> {
     if let Some(cached_langs) = cache.get(&user_id) {
         return cached_langs;
     }
 
-    let default_lang_codes = smallvec![String::from("ru"), String::from("be"), String::from("uk")];
+    let default_lang_codes = smallvec![
+        "ru".into(),
+        "be".into(),
+        "uk".into()
+    ];
 
     match get_user_settings(user_id).await {
         Ok(v) => {
-            let langs: SmallVec<[String; 3]> = v.allowed_langs.into_iter().map(|lang| lang.code).collect();
+            let langs: SmallVec<[SmartString; 3]> = v.allowed_langs.into_iter().map(|lang| lang.code).collect();
             cache.insert(user_id, langs.clone()).await;
             langs
         },
@@ -66,8 +71,8 @@ pub async fn create_or_update_user_settings(
     first_name: String,
     username: String,
     source: String,
-    allowed_langs: SmallVec<[String; 3]>,
-    cache: Cache<UserId, SmallVec<[String; 3]>>
+    allowed_langs: SmallVec<[SmartString; 3]>,
+    cache: Cache<UserId, SmallVec<[SmartString; 3]>>
 ) -> Result<UserSettings, Box<dyn std::error::Error + Send + Sync>> {
     cache.invalidate(&user_id).await;
 
diff --git a/src/bots_manager/mod.rs b/src/bots_manager/mod.rs
index 559060d..453cd7e 100644
--- a/src/bots_manager/mod.rs
+++ b/src/bots_manager/mod.rs
@@ -1,5 +1,7 @@
 pub mod bot_manager_client;
 
+use smartstring::alias::String as SmartString;
+
 use std::collections::HashMap;
 use std::net::SocketAddr;
 use std::sync::atomic::{AtomicBool, Ordering};
@@ -26,7 +28,7 @@ use crate::config;
 #[derive(Clone)]
 pub struct AppState {
     pub user_activity_cache: Cache<UserId, ()>,
-    pub user_langs_cache: Cache<UserId, SmallVec<[String; 3]>>,
+    pub user_langs_cache: Cache<UserId, SmallVec<[SmartString; 3]>>,
     pub chat_donation_notifications_cache: Cache<ChatId, ()>,
 }