diff --git a/src/api.rs b/src/api.rs
index 78613f1..7cf0826 100644
--- a/src/api.rs
+++ b/src/api.rs
@@ -4,8 +4,8 @@ use crate::db::{
 };
 use crate::smt::db::db::RocksDB;
 use crate::smt::entry::generate_registry_smt;
-use crate::utils::parse_request_param;
-use jsonrpc_http_server::jsonrpc_core::serde_json::{Map, Number};
+use crate::utils::{parse_request_param, Inserter};
+use jsonrpc_http_server::jsonrpc_core::serde_json::Map;
 use jsonrpc_http_server::jsonrpc_core::{Error, Params, Value};
 use log::info;
 
@@ -18,19 +18,10 @@ pub async fn register_rpc(params: Params, db: &RocksDB) -> Result<Value, Error>
         .map_err(|err| err.into())?;
     let block_number = get_syncer_tip_block_number().map_err(|err| err.into())?;
     let mut response = Map::new();
-    response.insert("smt_root_hash".to_string(), Value::String(root_hash));
-    response.insert(
-        "registry_smt_entry".to_string(),
-        Value::String(registry_entry),
-    );
-    response.insert(
-        "output_account_num".to_string(),
-        Value::Number(Number::from(output_account_num)),
-    );
-    response.insert(
-        "block_number".to_string(),
-        Value::Number(Number::from(block_number)),
-    );
+    response.insert_str("smt_root_hash", root_hash);
+    response.insert_str("registry_smt_entry", registry_entry);
+    response.insert_u64("output_account_num", output_account_num);
+    response.insert_u64("block_number", block_number);
     Ok(Value::Object(response))
 }
 
@@ -41,18 +32,12 @@ pub async fn check_registered_rpc(params: Params) -> Result<Value, Error> {
     let (registry_state, block_height) =
         check_lock_hashes_registered(lock_hashes).map_err(|err| err.into())?;
     let mut response = Map::new();
-    response.insert(
-        "registered".to_string(),
-        Value::Bool(registry_state != RegistryState::Unregister),
-    );
-    response.insert(
-        "block_number".to_string(),
-        Value::Number(Number::from(block_height)),
-    );
+    response.insert_bool("registered", registry_state != RegistryState::Unregister);
+    response.insert_u64("block_number", block_height);
     Ok(Value::Object(response))
 }
 
-pub async fn update_registered_ccid_rpc(db: &RocksDB) -> Result<Value, Error> {
+pub async fn update_ccid_rpc(db: &RocksDB) -> Result<Value, Error> {
     info!("Update registered ccid request");
     let lock_hashes = get_50_registered_lock_hashes().map_err(|err| err.into())?;
     let (root_hash, registry_entry, output_account_num) = generate_registry_smt(db, lock_hashes)
@@ -60,18 +45,9 @@ pub async fn update_registered_ccid_rpc(db: &RocksDB) -> Result<Value, Error> {
         .map_err(|err| err.into())?;
     let block_number = get_syncer_tip_block_number().map_err(|err| err.into())?;
     let mut response = Map::new();
-    response.insert("smt_root_hash".to_string(), Value::String(root_hash));
-    response.insert(
-        "registry_smt_entry".to_string(),
-        Value::String(registry_entry),
-    );
-    response.insert(
-        "output_account_num".to_string(),
-        Value::Number(Number::from(output_account_num)),
-    );
-    response.insert(
-        "block_number".to_string(),
-        Value::Number(Number::from(block_number)),
-    );
+    response.insert_str("smt_root_hash", root_hash);
+    response.insert_str("registry_smt_entry", registry_entry);
+    response.insert_u64("output_account_num", output_account_num);
+    response.insert_u64("block_number", block_number);
     Ok(Value::Object(response))
 }
diff --git a/src/main.rs b/src/main.rs
index d56d034..cc802f2 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -2,7 +2,7 @@
 extern crate diesel;
 extern crate dotenv;
 
-use crate::api::{check_registered_rpc, register_rpc, update_registered_ccid_rpc};
+use crate::api::{check_registered_rpc, register_rpc, update_ccid_rpc};
 use crate::db::{init_connection_pool, SqlConnectionPool};
 use crate::smt::db::db::RocksDB;
 use dotenv::dotenv;
@@ -32,9 +32,7 @@ fn main() {
 
     let mut io = IoHandler::default();
     io.add_method("register_cota_cells", |req| register_rpc(req, &DB));
-    io.add_method("update_registered_ccid", |_req| {
-        update_registered_ccid_rpc(&DB)
-    });
+    io.add_method("update_registered_ccid", |_req| update_ccid_rpc(&DB));
     io.add_method("check_registered_lock_hashes", check_registered_rpc);
 
     let server = ServerBuilder::new(io)
diff --git a/src/utils.rs b/src/utils.rs
index 28ffdda..efc0e83 100644
--- a/src/utils.rs
+++ b/src/utils.rs
@@ -1,5 +1,6 @@
 use crate::error::Error;
 use hex;
+use jsonrpc_http_server::jsonrpc_core::serde_json::{Map, Number};
 use jsonrpc_http_server::jsonrpc_core::Value;
 use std::convert::TryInto;
 
@@ -48,6 +49,34 @@ pub fn parse_bytes_n<const N: usize>(value: String) -> Result<[u8; N], Error> {
     Ok(parse_n(vec))
 }
 
+pub trait Inserter {
+    fn insert_hex(&mut self, k: &str, v: &[u8]) -> Option<Value>;
+    fn insert_u64(&mut self, k: &str, v: u64) -> Option<Value>;
+    fn insert_str(&mut self, k: &str, v: String) -> Option<Value>;
+    fn insert_bool(&mut self, k: &str, v: bool) -> Option<Value>;
+}
+
+impl Inserter for Map<String, Value> {
+    fn insert_hex(&mut self, k: &str, v: &[u8]) -> Option<Value> {
+        self.insert(
+            k.to_string(),
+            Value::String(format!("0x{}", hex::encode(v))),
+        )
+    }
+
+    fn insert_u64(&mut self, k: &str, v: u64) -> Option<Value> {
+        self.insert(k.to_string(), Value::Number(Number::from(v)))
+    }
+
+    fn insert_str(&mut self, k: &str, v: String) -> Option<Value> {
+        self.insert(k.to_string(), Value::String(v))
+    }
+
+    fn insert_bool(&mut self, k: &str, v: bool) -> Option<Value> {
+        self.insert(k.to_string(), Value::Bool(v))
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;