diff --git a/backend/Cargo.lock b/backend/Cargo.lock
index 08f59a2..c367e74 100644
--- a/backend/Cargo.lock
+++ b/backend/Cargo.lock
@@ -3537,6 +3537,7 @@ dependencies = [
  "quote",
  "regex",
  "syn",
+ "url",
 ]
 
 [[package]]
diff --git a/backend/Cargo.toml b/backend/Cargo.toml
index 91ce1e9..e6cd1b2 100644
--- a/backend/Cargo.toml
+++ b/backend/Cargo.toml
@@ -30,7 +30,11 @@ sqlx = { version = "0.8.5", features = [
     "runtime-tokio-rustls",
 ] }
 tokio = { version = "1.45.0", features = ["full"] }
-utoipa = { version = "5.4.0", features = ["actix_extras"] }
+utoipa = { version = "5.4.0", features = [
+    "actix_extras",
+    "non_strict_integers",
+    "url",
+] }
 utoipa-redoc = { version = "6.0.0", features = ["actix-web"] }
 
 server.path = "server"
diff --git a/backend/feature/auth/src/adapter/delivery/user_response_dto.rs b/backend/feature/auth/src/adapter/delivery/user_response_dto.rs
index f040f2d..00e0b18 100644
--- a/backend/feature/auth/src/adapter/delivery/user_response_dto.rs
+++ b/backend/feature/auth/src/adapter/delivery/user_response_dto.rs
@@ -7,6 +7,8 @@ use crate::domain::entity::user::User;
 pub struct UserResponseDto {
     pub id: i32,
     pub displayed_name: String,
+
+    #[schema(format = Email)]
     pub email: String,
 }
 
diff --git a/backend/feature/post/src/adapter/delivery/color_request_dto.rs b/backend/feature/post/src/adapter/delivery/color_request_dto.rs
index f6838a3..bd15888 100644
--- a/backend/feature/post/src/adapter/delivery/color_request_dto.rs
+++ b/backend/feature/post/src/adapter/delivery/color_request_dto.rs
@@ -5,16 +5,9 @@ use crate::domain::entity::color::Color;
 
 #[derive(Deserialize, ToSchema)]
 pub struct ColorRequestDto {
-    #[schema(maximum = 255)]
     pub red: u8,
-
-    #[schema(maximum = 255)]
     pub green: u8,
-
-    #[schema(maximum = 255)]
     pub blue: u8,
-
-    #[schema(maximum = 255)]
     pub alpha: u8,
 }
 
diff --git a/backend/feature/post/src/adapter/delivery/color_response_dto.rs b/backend/feature/post/src/adapter/delivery/color_response_dto.rs
index 7e64681..274f95a 100644
--- a/backend/feature/post/src/adapter/delivery/color_response_dto.rs
+++ b/backend/feature/post/src/adapter/delivery/color_response_dto.rs
@@ -5,16 +5,9 @@ use crate::domain::entity::color::Color;
 
 #[derive(Serialize, ToSchema)]
 pub struct ColorResponseDto {
-    #[schema(maximum = 255)]
     pub red: u8,
-
-    #[schema(maximum = 255)]
     pub green: u8,
-
-    #[schema(maximum = 255)]
     pub blue: u8,
-
-    #[schema(maximum = 255)]
     pub alpha: u8,
 }
 
diff --git a/backend/feature/post/src/adapter/delivery/create_post_request_dto.rs b/backend/feature/post/src/adapter/delivery/create_post_request_dto.rs
index 053b6a6..c242d0a 100644
--- a/backend/feature/post/src/adapter/delivery/create_post_request_dto.rs
+++ b/backend/feature/post/src/adapter/delivery/create_post_request_dto.rs
@@ -8,10 +8,12 @@ use crate::domain::entity::{post::Post, post_info::PostInfo};
 pub struct CreatePostRequestDto {
     pub title: String,
     pub description: String,
-    pub preview_image_url: String,
     pub content: String,
     pub label_ids: Vec<i32>,
 
+    #[schema(format = Uri)]
+    pub preview_image_url: String,
+
     #[schema(required, format = DateTime)]
     pub published_time: Option<String>,
 }
diff --git a/backend/feature/post/src/adapter/delivery/post_info_response_dto.rs b/backend/feature/post/src/adapter/delivery/post_info_response_dto.rs
index 176b9c3..1a5e94e 100644
--- a/backend/feature/post/src/adapter/delivery/post_info_response_dto.rs
+++ b/backend/feature/post/src/adapter/delivery/post_info_response_dto.rs
@@ -10,9 +10,11 @@ pub struct PostInfoResponseDto {
     pub id: i32,
     pub title: String,
     pub description: String,
-    pub preview_image_url: String,
     pub labels: Vec<LabelResponseDto>,
 
+    #[schema(format = Uri)]
+    pub preview_image_url: String,
+
     #[schema(format = DateTime)]
     pub published_time: Option<String>,
 }
diff --git a/backend/feature/post/src/adapter/delivery/update_post_request_dto.rs b/backend/feature/post/src/adapter/delivery/update_post_request_dto.rs
index 7ae2128..29f96a7 100644
--- a/backend/feature/post/src/adapter/delivery/update_post_request_dto.rs
+++ b/backend/feature/post/src/adapter/delivery/update_post_request_dto.rs
@@ -8,10 +8,12 @@ use crate::domain::entity::{post::Post, post_info::PostInfo};
 pub struct UpdatePostRequestDto {
     pub title: String,
     pub description: String,
-    pub preview_image_url: String,
     pub content: String,
     pub label_ids: Vec<i32>,
 
+    #[schema(format = Uri)]
+    pub preview_image_url: String,
+
     #[schema(required, format = DateTime)]
     pub published_time: Option<String>,
 }