diff --git a/core/src/error.rs b/core/src/error.rs
new file mode 100644
index 0000000..a76d2ec
--- /dev/null
+++ b/core/src/error.rs
@@ -0,0 +1,9 @@
+pub struct Status {
+    pub code: u16,
+}
+
+pub const InvalidCredentialsError: ServiceError<String> = ServiceError(Status { code: 401 }, 
+    "Invalid credentials".to_string());
+pub const JwtError: ServiceError<String> = ServiceError(Status { code: 500 }, 
+    "Error while encoding JWT".to_string());
+pub struct ServiceError<R>(pub Status, pub R);
\ No newline at end of file
diff --git a/core/src/lib.rs b/core/src/lib.rs
index 942af37..71b5ace 100644
--- a/core/src/lib.rs
+++ b/core/src/lib.rs
@@ -3,6 +3,7 @@ mod query;
 pub mod crypto;
 pub mod token;
 pub mod services;
+pub mod error;
 
 pub use mutation::*;
 pub use query::*;