diff --git a/src/provider.rs b/src/provider.rs
index 66ecb54..ca86a57 100644
--- a/src/provider.rs
+++ b/src/provider.rs
@@ -25,6 +25,7 @@ pub trait Provider {
 ///
 /// See [Using OAuth 2.0 to Access Google
 /// APIs](https://developers.google.com/identity/protocols/OAuth2).
+#[derive(Debug)]
 pub struct Google;
 impl Provider for Google {
     type Lifetime = Expiring;
@@ -36,6 +37,7 @@ impl Provider for Google {
 /// GitHub OAuth 2.0 provider.
 ///
 /// See [OAuth, GitHub Developer Guide](https://developer.github.com/v3/oauth/).
+#[derive(Debug)]
 pub struct GitHub;
 impl Provider for GitHub {
     type Lifetime = Static;
@@ -47,6 +49,7 @@ impl Provider for GitHub {
 /// Imgur OAuth 2.0 provider.
 ///
 /// See [OAuth 2.0, Imgur](https://api.imgur.com/oauth2).
+#[derive(Debug)]
 pub struct Imgur;
 impl Provider for Imgur {
     type Lifetime = Expiring;
diff --git a/src/token/bearer.rs b/src/token/bearer.rs
index ddd2b8a..3775b0f 100644
--- a/src/token/bearer.rs
+++ b/src/token/bearer.rs
@@ -5,6 +5,7 @@ use super::{Token, Lifetime};
 /// The bearer token type.
 ///
 /// See [RFC 6750](http://tools.ietf.org/html/rfc6750).
+#[derive(Debug)]
 pub struct Bearer<L: Lifetime> {
     access_token: String,
     scope: Option<String>,
diff --git a/src/token/expiring.rs b/src/token/expiring.rs
index 4c2ae45..fe88947 100644
--- a/src/token/expiring.rs
+++ b/src/token/expiring.rs
@@ -3,6 +3,7 @@ use chrono::{DateTime, UTC};
 use super::Lifetime;
 
 /// An expiring token.
+#[derive(Debug)]
 pub struct Expiring {
     refresh_token: String,
     expires: DateTime<UTC>,
diff --git a/src/token/statik.rs b/src/token/statik.rs
index 1dbec00..63655fc 100644
--- a/src/token/statik.rs
+++ b/src/token/statik.rs
@@ -1,6 +1,7 @@
 use super::Lifetime;
 
 /// A static, non-expiring token.
+#[derive(Debug)]
 pub struct Static;
 
 impl Lifetime for Static {