diff --git a/Cargo.toml b/Cargo.toml
index 7c9821e..9f320c4 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,7 +1,7 @@
 [package]
 
 name = "yup-oauth2"
-version = "0.2.2"
+version = "0.3.0"
 authors = ["Sebastian Thiel <byronimo@gmail.com>"]
 repository = "https://github.com/Byron/yup-oauth2"
 description = "A partial oauth2 implementation, providing the 'device' authorization flow"
diff --git a/examples/auth.rs b/examples/auth.rs
index 84c712c..21e57db 100644
--- a/examples/auth.rs
+++ b/examples/auth.rs
@@ -1,4 +1,5 @@
-#![feature(env, collections, old_io, std_misc)]
+#![feature(collections, old_io, std_misc, exit_status)]
+#![allow(deprecated)]
 extern crate "yup-oauth2" as oauth2;
 extern crate "yup-hyper-mock" as mock;
 extern crate hyper;
diff --git a/src/helper.rs b/src/helper.rs
index 6327da9..a931031 100644
--- a/src/helper.rs
+++ b/src/helper.rs
@@ -81,10 +81,14 @@ pub struct Authenticator<D, S, C, NC> {
 }
 
 /// A provider for authorization tokens, yielding tokens valid for a given scope.
+/// The `api_key()` method is an alternative in case there are no scopes or
+/// if no user is involved.
 pub trait GetToken {
     fn token<'b, I, T>(&mut self, scopes: I) -> Option<Token>
         where   T: Str + Ord,
                 I: IntoIterator<Item=&'b T>;
+
+    fn api_key(&mut self) -> Option<String>;
 }
 
 impl<D, S, C, NC> Authenticator<D, S, C, NC>
@@ -245,6 +249,13 @@ impl<D, S, C, NC> GetToken for Authenticator<D, S, C, NC>
             },
         }
     }
+
+    fn api_key(&mut self) -> Option<String> {
+        if self.secret.client_id.len() == 0 {
+            return None
+        }
+        Some(self.secret.client_id.clone())
+    }
 }
 
 
diff --git a/src/lib.rs b/src/lib.rs
index 645e65f..69d5251 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,4 +1,5 @@
-#![feature(io, old_io, std_misc, core, hash)]
+#![feature(old_io, std_misc, core, hash)]
+#![allow(deprecated)]
 //! This library can be used to acquire oauth2.0 authentication for services.
 //! At the time of writing, only one way of doing so is implemented, the [device flow](https://developers.google.com/youtube/v3/guides/authentication#devices), along with a flow 
 //! for [refreshing tokens](https://developers.google.com/youtube/v3/guides/authentication#devices)