diff --git a/src/api/key.rs b/src/api/key.rs
new file mode 100755
--- /dev/null
+++ b/src/api/key.rs
@@ -0,0 +1,11 @@
+//! # API key, with associated metadata.
+//!
+//! This module provides API key trait.
+
+use std::collections::HashMap;
+
+/// Represents an API key
+pub struct APIKey {
+    pub key: String,
+    pub metadata: HashMap<String, String>,
+}
diff --git a/src/api/mod.rs b/src/api/mod.rs
--- a/src/api/mod.rs
+++ b/src/api/mod.rs
@@ -7,3 +7,4 @@
      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
 
 pub mod replies;
+pub mod key;