diff --git a/Cargo.toml b/Cargo.toml
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "limiting-factor"
-version = "0.3.0"
+version = "0.4.0"
 authors = [
     "Sébastien Santoro <dereckson@espace-win.org>",
 ]
diff --git a/src/api/replies.rs b/src/api/replies.rs
--- a/src/api/replies.rs
+++ b/src/api/replies.rs
@@ -135,6 +135,14 @@
      Helper methods to prepare API responses
      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
 
+pub fn build_not_found_response() -> Failure {
+    Failure::from(Status::NotFound)
+}
+
+pub fn build_bad_request_response() -> Failure {
+    Failure::from(Status::BadRequest)
+}
+
 pub fn build_internal_server_error_response(message: &str) -> Failure {
     warn!(target:"api", "{}", message);