diff --git a/src/ledger/transaction.rs b/src/ledger/transaction.rs
index 4aad6ea..43b158a 100644
--- a/src/ledger/transaction.rs
+++ b/src/ledger/transaction.rs
@@ -9,6 +9,7 @@ use axum_macros::debug_handler;
 use diesel::dsl::exists;
 use diesel::prelude::*;
 use std::fmt;
+use chrono::ParseResult;
 // use diesel::update;
 use serde::{Deserialize, Serialize};
 // use serde_json::to_string;
@@ -29,7 +30,7 @@ pub struct SubmitTransactionRequest {
     book_id: i64,
     category_id: i64,
     tag_ids: Vec<i64>,
-    time: String,
+    time: String, // RFC 3339 "2020-04-12T22:10:57+02:00"
     amounts: Vec<SubmitTransactionAmountRequest>,
 }
 
@@ -192,6 +193,14 @@ pub async fn create_transaction(
     }
 
     // 2. build and insert into db
+    let datetime_tz = chrono::DateTime::parse_from_rfc3339(payload.time.as_str());
+    let datetime = match datetime_tz {
+        Ok(dt) => dt,
+        Err(_) => {
+            return Err((StatusCode::BAD_REQUEST, "invalid datetime, must be RFC 3339".to_string()))
+        }
+    };
+    let datetime_utc = datetime.with_timezone(&Utc);
 
     let mut transaction_resp: CreateTransactionResponse;
     let mut amount_ids: Vec<i64> = Vec::new();
@@ -206,7 +215,7 @@ pub async fn create_transaction(
                     description: payload.description,
                     category_id: payload.category_id,
                     // time: payload
-                    time: Utc::now(),
+                    time: datetime_utc,
                 };
                 let inserted_transactions = diesel::insert_into(schema::transactions::table)
                     .values(&new_transaction)
@@ -268,13 +277,23 @@ pub async fn update_transaction(
         .await
         .map_err(util::req::internal_error)?;
     let now = Utc::now().naive_utc();
+    let datetime_tz = chrono::DateTime::parse_from_rfc3339(payload.time.as_str());
+    let datetime = match datetime_tz {
+        Ok(dt) => dt,
+        Err(_) => {
+            return Err((StatusCode::BAD_REQUEST, "invalid datetime, must be RFC 3339".to_string()))
+        }
+    };
+    let datetime_utc = datetime.with_timezone(&Utc);
     let res = conn
         .interact(move |conn| {
             diesel::update(schema::transactions::table)
                 .filter(schema::transactions::id.eq(id))
                 .filter(schema::transactions::uid.eq(uid))
                 .set((
+                    schema::transactions::category_id.eq(payload.category_id),
                     schema::transactions::description.eq(payload.description),
+                    schema::transactions::time.eq(datetime_utc),
                     schema::transactions::update_at.eq(now),
                 ))
                 .execute(conn)