diff --git a/Cargo.lock b/Cargo.lock
index 754805a..5458cb0 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -348,6 +348,17 @@ dependencies = [
  "slab",
 ]
 
+[[package]]
+name = "getrandom"
+version = "0.2.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "be4136b2a15dd319360be1c07d9933517ccf0be8f16bf62a3bee4f0d618df427"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "wasi",
+]
+
 [[package]]
 name = "gimli"
 version = "0.27.3"
@@ -379,6 +390,12 @@ version = "0.12.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8a9ee70c43aaf417c914396645a0fa852624801b24ebb7ae78fe8272889ac888"
 
+[[package]]
+name = "heck"
+version = "0.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "95505c38b4572b2d910cecb0281560f54b440a19336cbbcb27bf6ce6adc6f5a8"
+
 [[package]]
 name = "hermit-abi"
 version = "0.3.1"
@@ -600,9 +617,11 @@ dependencies = [
  "lazy-regex",
  "serde",
  "serde_json",
+ "strum_macros",
  "tokio",
  "tower-cookies",
  "tower-http",
+ "uuid",
 ]
 
 [[package]]
@@ -841,6 +860,12 @@ version = "0.3.27"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "26072860ba924cbfa98ea39c8c19b4dd6a4a25423dbdf219c1eca91aa0cf6964"
 
+[[package]]
+name = "ppv-lite86"
+version = "0.2.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5b40af805b3121feab8a3c29f04d8ad262fa8e0561883e7653e024ae4479e6de"
+
 [[package]]
 name = "proc-macro2"
 version = "1.0.63"
@@ -875,6 +900,36 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "rand"
+version = "0.8.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "34af8d1a0e25924bc5b7c43c079c942339d8f0a8b57c39049bef581b46327404"
+dependencies = [
+ "libc",
+ "rand_chacha",
+ "rand_core",
+]
+
+[[package]]
+name = "rand_chacha"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e6c10a63a0fa32252be49d21e7709d4d4baf8d231c2dbce1eaa8141b9b127d88"
+dependencies = [
+ "ppv-lite86",
+ "rand_core",
+]
+
+[[package]]
+name = "rand_core"
+version = "0.6.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ec0be4795e2f6a28069bec0b5ff3e2ac9bafc99e6a9a7dc3547996c5c816922c"
+dependencies = [
+ "getrandom",
+]
+
 [[package]]
 name = "redox_syscall"
 version = "0.3.5"
@@ -1131,6 +1186,19 @@ dependencies = [
  "windows-sys 0.48.0",
 ]
 
+[[package]]
+name = "strum_macros"
+version = "0.25.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "23dc1fa9ac9c169a78ba62f0b841814b7abae11bdd047b9c58f893439e309ea0"
+dependencies = [
+ "heck",
+ "proc-macro2",
+ "quote",
+ "rustversion",
+ "syn",
+]
+
 [[package]]
 name = "syn"
 version = "2.0.22"
@@ -1416,6 +1484,16 @@ dependencies = [
  "percent-encoding",
 ]
 
+[[package]]
+name = "uuid"
+version = "1.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "79daa5ed5740825c40b389c5e50312b9c86df53fccd33f281df655642b43869d"
+dependencies = [
+ "getrandom",
+ "rand",
+]
+
 [[package]]
 name = "vcpkg"
 version = "0.2.15"
diff --git a/Cargo.toml b/Cargo.toml
index d32e180..330aaa8 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -17,6 +17,8 @@ tower-cookies = "0.9"
 # Others
 lazy-regex = "3"
 async-trait = "0.1"
+strum_macros = "0.25"
+uuid = { version = "1", features = ["v4", "fast-rng"] }
 
 [dev-dependencies]
 anyhow = "1"
diff --git a/src/error.rs b/src/error.rs
index b46c2ed..8452bab 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -3,7 +3,7 @@ use axum::response::{IntoResponse, Response};
 
 pub type Result<T> = core::result::Result<T, Error>;
 
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, strum_macros::AsRefStr)]
 pub enum Error {
     LoginFail,
 
@@ -16,11 +16,50 @@ pub enum Error {
     PropertyDeleteFailIdNotFound { id: u64 },
 }
 
-/// FIXME: return different status codes for different errors
+impl Error {
+    pub fn client_status_and_error(&self) -> (StatusCode, ClientError) {
+        match self {
+            // -- Login.
+            Self::LoginFail => (StatusCode::UNAUTHORIZED, ClientError::LOGIN_FAIL),
+
+            // -- Auth.
+            Self::AuthFailNoAuthTokenCookie
+            | Self::AuthFailTokenWrongFormat
+            | Self::AuthFailCtxNotInRequestExt => (StatusCode::FORBIDDEN, ClientError::NO_AUTH),
+
+            // -- Model.
+            Self::PropertyDeleteFailIdNotFound { .. } => {
+                (StatusCode::BAD_REQUEST, ClientError::INVALID_PARAMS)
+            }
+
+            // -- Fallback.
+            _ => (
+                StatusCode::INTERNAL_SERVER_ERROR,
+                ClientError::SERVICE_ERROR,
+            ),
+        }
+    }
+}
+
 impl IntoResponse for Error {
     fn into_response(self) -> Response {
         println!("->> {:<12} - {self:?}", "INTO_RESPONSE");
 
-        (StatusCode::INTERNAL_SERVER_ERROR, "UNHANDLED_CLIENT_ERROR").into_response()
+        // Create a placeholder Axum response.
+        let mut response = StatusCode::INTERNAL_SERVER_ERROR.into_response();
+
+        // Insert the Error into the response.
+        response.extensions_mut().insert(self);
+
+        response
     }
 }
+
+#[derive(Debug, strum_macros::AsRefStr)]
+#[allow(non_camel_case_types)]
+pub enum ClientError {
+    LOGIN_FAIL,
+    NO_AUTH,
+    INVALID_PARAMS,
+    SERVICE_ERROR,
+}
diff --git a/src/main.rs b/src/main.rs
index 05b5727..b8eb052 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -13,8 +13,10 @@ use axum::routing::{get, get_service};
 use axum::{middleware, Json, Router};
 use axum::Server;
 use serde::Deserialize;
+use serde_json::json;
 use tower_http::services::ServeDir;
 use tower_cookies::CookieManagerLayer;
+use uuid::Uuid;
 
 mod ctx;
 mod error;
@@ -56,10 +58,35 @@ async fn main() -> Result<()>{
 ///
 /// * `res`: the response to map
 async fn main_response_mapper(res: Response) -> Response {
-    println!("->> {:<12} - main_response_mapper", "HANDLER");
+    println!("->> {:<12} - main_response_mapper", "RES_MAPPER");
+    let uuid = Uuid::new_v4();
+
+    // -- Get the eventual response error.
+    let service_error = res.extensions().get::<Error>();
+    let client_status_error = service_error.map(|se| se.client_status_and_error());
+
+    // -- If client error, build the new response
+    let error_response = client_status_error
+        .as_ref()
+        .map(|(status_code, client_error)| {
+            let client_error_body = json!({
+                "error": {
+                    "type": client_error.as_ref(),
+                    "req_uuid": uuid.to_string(),
+                }
+            });
+
+            println!("    ->> client_error_body: {client_error_body}");
+
+            // Build the new response from the client error body.
+            (*status_code, Json(client_error_body)).into_response()
+        });
+
+    // -- TODO: Build and log the server log line.
+    println!("    ->> server log line - {uuid} - Error: {service_error:?}");
 
     println!();
-    res
+    error_response.unwrap_or(res)
 }
 
 /// Serve static files