diff --git a/crates/http-api-bindings/src/lib.rs b/crates/http-api-bindings/src/lib.rs
index fc743ca..83c09cd 100644
--- a/crates/http-api-bindings/src/lib.rs
+++ b/crates/http-api-bindings/src/lib.rs
@@ -1,32 +1,31 @@
 mod fastchat;
 mod vertex_ai;
 
+use std::sync::Arc;
+
 use fastchat::FastChatEngine;
 use serde_json::Value;
 use tabby_inference::TextGeneration;
 use vertex_ai::VertexAIEngine;
 
-pub fn create(model: &str) -> (Box<dyn TextGeneration>, String) {
+pub fn create(model: &str) -> (Arc<dyn TextGeneration>, String) {
     let params = serde_json::from_str(model).expect("Failed to parse model string");
     let kind = get_param(&params, "kind");
     if kind == "vertex-ai" {
         let api_endpoint = get_param(&params, "api_endpoint");
         let authorization = get_param(&params, "authorization");
-        let engine = Box::new(VertexAIEngine::create(
-            api_endpoint.as_str(),
-            authorization.as_str(),
-        ));
-        (engine, VertexAIEngine::prompt_template())
+        let engine = VertexAIEngine::create(api_endpoint.as_str(), authorization.as_str());
+        (Arc::new(engine), VertexAIEngine::prompt_template())
     } else if kind == "fastchat" {
         let model_name = get_param(&params, "model_name");
         let api_endpoint = get_param(&params, "api_endpoint");
         let authorization = get_param(&params, "authorization");
-        let engine = Box::new(FastChatEngine::create(
+        let engine = FastChatEngine::create(
             api_endpoint.as_str(),
             model_name.as_str(),
             authorization.as_str(),
-        ));
-        (engine, FastChatEngine::prompt_template())
+        );
+        (Arc::new(engine), FastChatEngine::prompt_template())
     } else {
         panic!("Only vertex_ai and fastchat are supported for http backend");
     }
diff --git a/crates/tabby-common/src/api/code.rs b/crates/tabby-common/src/api/code.rs
index 47cbe8e..2f07329 100644
--- a/crates/tabby-common/src/api/code.rs
+++ b/crates/tabby-common/src/api/code.rs
@@ -55,5 +55,3 @@ pub trait CodeSearch: Send + Sync {
         offset: usize,
     ) -> Result<SearchResponse, CodeSearchError>;
 }
-
-pub type BoxCodeSearch = Box<dyn CodeSearch>;
diff --git a/crates/tabby/src/chat.rs b/crates/tabby/src/chat.rs
index 0d1d778..1f2c91a 100644
--- a/crates/tabby/src/chat.rs
+++ b/crates/tabby/src/chat.rs
@@ -35,12 +35,12 @@ pub struct ChatCompletionChunk {
 }
 
 pub struct ChatService {
-    engine: Arc<Box<dyn TextGeneration>>,
+    engine: Arc<dyn TextGeneration>,
     prompt_builder: ChatPromptBuilder,
 }
 
 impl ChatService {
-    pub fn new(engine: Arc<Box<dyn TextGeneration>>, chat_template: String) -> Self {
+    pub fn new(engine: Arc<dyn TextGeneration>, chat_template: String) -> Self {
         Self {
             engine,
             prompt_builder: ChatPromptBuilder::new(chat_template),
diff --git a/crates/tabby/src/search.rs b/crates/tabby/src/search.rs
index b7de2da..7ca3188 100644
--- a/crates/tabby/src/search.rs
+++ b/crates/tabby/src/search.rs
@@ -3,7 +3,7 @@ use std::{sync::Arc, time::Duration};
 use anyhow::Result;
 use async_trait::async_trait;
 use tabby_common::{
-    api::code::{BoxCodeSearch, CodeSearch, CodeSearchError, Hit, HitDocument, SearchResponse},
+    api::code::{CodeSearch, CodeSearchError, Hit, HitDocument, SearchResponse},
     index::{self, register_tokenizers, CodeSearchSchema},
     path,
 };
@@ -156,8 +156,8 @@ impl CodeSearchService {
     }
 }
 
-pub fn create_code_search() -> BoxCodeSearch {
-    Box::new(CodeSearchService::new())
+pub fn create_code_search() -> impl CodeSearch {
+    CodeSearchService::new()
 }
 
 #[async_trait]
diff --git a/crates/tabby/src/serve/completions.rs b/crates/tabby/src/serve/completions.rs
index 4a66220..f630b6d 100644
--- a/crates/tabby/src/serve/completions.rs
+++ b/crates/tabby/src/serve/completions.rs
@@ -5,7 +5,7 @@ use std::sync::Arc;
 use axum::{extract::State, Json};
 use hyper::StatusCode;
 use serde::{Deserialize, Serialize};
-use tabby_common::{api::code::BoxCodeSearch, events, languages::get_language};
+use tabby_common::{api::code::CodeSearch, events, languages::get_language};
 use tabby_inference::{TextGeneration, TextGenerationOptionsBuilder};
 use tracing::{debug, instrument};
 use utoipa::ToSchema;
@@ -202,14 +202,14 @@ async fn build_prompt(
 }
 
 pub struct CompletionState {
-    engine: Arc<Box<dyn TextGeneration>>,
+    engine: Arc<dyn TextGeneration>,
     prompt_builder: prompt::PromptBuilder,
 }
 
 impl CompletionState {
     pub fn new(
-        engine: Arc<Box<dyn TextGeneration>>,
-        code: Arc<BoxCodeSearch>,
+        engine: Arc<dyn TextGeneration>,
+        code: Arc<dyn CodeSearch>,
         prompt_template: Option<String>,
     ) -> Self {
         Self {
diff --git a/crates/tabby/src/serve/completions/prompt.rs b/crates/tabby/src/serve/completions/prompt.rs
index a863d73..742e5bf 100644
--- a/crates/tabby/src/serve/completions/prompt.rs
+++ b/crates/tabby/src/serve/completions/prompt.rs
@@ -4,7 +4,7 @@ use lazy_static::lazy_static;
 use regex::Regex;
 use strfmt::strfmt;
 use tabby_common::{
-    api::code::{BoxCodeSearch, CodeSearchError},
+    api::code::{CodeSearch, CodeSearchError},
     languages::get_language,
 };
 use textdistance::Algorithm;
@@ -18,11 +18,11 @@ static MAX_SIMILARITY_THRESHOLD: f32 = 0.9;
 
 pub struct PromptBuilder {
     prompt_template: Option<String>,
-    code: Option<Arc<BoxCodeSearch>>,
+    code: Option<Arc<dyn CodeSearch>>,
 }
 
 impl PromptBuilder {
-    pub fn new(prompt_template: Option<String>, code: Option<Arc<BoxCodeSearch>>) -> Self {
+    pub fn new(prompt_template: Option<String>, code: Option<Arc<dyn CodeSearch>>) -> Self {
         PromptBuilder {
             prompt_template,
             code,
@@ -106,7 +106,7 @@ fn build_prefix(language: &str, prefix: &str, snippets: &[Snippet]) -> String {
     format!("{}\n{}", comments, prefix)
 }
 
-async fn collect_snippets(code: &BoxCodeSearch, language: &str, text: &str) -> Vec<Snippet> {
+async fn collect_snippets(code: &dyn CodeSearch, language: &str, text: &str) -> Vec<Snippet> {
     let mut ret = Vec::new();
     let mut tokens = tokenize_text(text);
 
diff --git a/crates/tabby/src/serve/engine.rs b/crates/tabby/src/serve/engine.rs
index 8e28d12..ce35914 100644
--- a/crates/tabby/src/serve/engine.rs
+++ b/crates/tabby/src/serve/engine.rs
@@ -1,4 +1,4 @@
-use std::{fs, path::PathBuf};
+use std::{fs, path::PathBuf, sync::Arc};
 
 use serde::Deserialize;
 use tabby_common::registry::{parse_model_id, ModelRegistry, GGML_MODEL_RELATIVE_PATH};
@@ -9,7 +9,7 @@ use crate::fatal;
 pub async fn create_engine(
     model_id: &str,
     args: &crate::serve::ServeArgs,
-) -> (Box<dyn TextGeneration>, EngineInfo) {
+) -> (Arc<dyn TextGeneration>, EngineInfo) {
     #[cfg(feature = "experimental-http")]
     if args.device == crate::serve::Device::ExperimentalHttp {
         let (engine, prompt_template) = http_api_bindings::create(model_id);
@@ -31,7 +31,7 @@ pub async fn create_engine(
             args.parallelism,
         );
         let engine_info = EngineInfo::read(path.join("tabby.json"));
-        (engine, engine_info)
+        (Arc::new(engine), engine_info)
     } else {
         let (registry, name) = parse_model_id(model_id);
         let registry = ModelRegistry::new(registry).await;
@@ -39,7 +39,7 @@ pub async fn create_engine(
         let model_info = registry.get_model_info(name);
         let engine = create_ggml_engine(&args.device, &model_path, args.parallelism);
         (
-            engine,
+            Arc::new(engine),
             EngineInfo {
                 prompt_template: model_info.prompt_template.clone(),
                 chat_template: model_info.chat_template.clone(),
@@ -65,7 +65,7 @@ fn create_ggml_engine(
     device: &super::Device,
     model_path: &str,
     parallelism: u8,
-) -> Box<dyn TextGeneration> {
+) -> impl TextGeneration {
     let options = llama_cpp_bindings::LlamaTextGenerationOptionsBuilder::default()
         .model_path(model_path.to_owned())
         .use_gpu(device.ggml_use_gpu())
@@ -73,5 +73,5 @@ fn create_ggml_engine(
         .build()
         .unwrap();
 
-    Box::new(llama_cpp_bindings::LlamaTextGeneration::new(options))
+    llama_cpp_bindings::LlamaTextGeneration::new(options)
 }
diff --git a/crates/tabby/src/serve/mod.rs b/crates/tabby/src/serve/mod.rs
index 7bee9df..9298814 100644
--- a/crates/tabby/src/serve/mod.rs
+++ b/crates/tabby/src/serve/mod.rs
@@ -189,7 +189,6 @@ async fn api_router(args: &ServeArgs, config: &Config) -> Router {
                 prompt_template, ..
             },
         ) = create_engine(&args.model, args).await;
-        let engine = Arc::new(engine);
         let state =
             completions::CompletionState::new(engine.clone(), code.clone(), prompt_template);
         Arc::new(state)
@@ -200,7 +199,6 @@ async fn api_router(args: &ServeArgs, config: &Config) -> Router {
         let Some(chat_template) = chat_template else {
             panic!("Chat model requires specifying prompt template");
         };
-        let engine = Arc::new(engine);
         let state = ChatService::new(engine, chat_template);
         Some(Arc::new(state))
     } else {
diff --git a/crates/tabby/src/serve/search.rs b/crates/tabby/src/serve/search.rs
index 28a2a67..99edade 100644
--- a/crates/tabby/src/serve/search.rs
+++ b/crates/tabby/src/serve/search.rs
@@ -7,7 +7,7 @@ use axum::{
 };
 use hyper::StatusCode;
 use serde::Deserialize;
-use tabby_common::api::code::{BoxCodeSearch, CodeSearchError, SearchResponse};
+use tabby_common::api::code::{CodeSearch, CodeSearchError, SearchResponse};
 use tracing::{instrument, warn};
 use utoipa::IntoParams;
 
@@ -36,7 +36,7 @@ pub struct SearchQuery {
     )]
 #[instrument(skip(state, query))]
 pub async fn search(
-    State(state): State<Arc<BoxCodeSearch>>,
+    State(state): State<Arc<dyn CodeSearch>>,
     query: Query<SearchQuery>,
 ) -> Result<Json<SearchResponse>, StatusCode> {
     match state