diff --git a/reqwest-middleware/src/client.rs b/reqwest-middleware/src/client.rs
index 8a48fad..af6c998 100644
--- a/reqwest-middleware/src/client.rs
+++ b/reqwest-middleware/src/client.rs
@@ -14,6 +14,7 @@ use crate::RequestInitialiser;
 /// A `ClientBuilder` is used to build a [`ClientWithMiddleware`].
 ///
 /// [`ClientWithMiddleware`]: crate::ClientWithMiddleware
+#[derive(Debug)]
 pub struct ClientBuilder {
     client: Client,
     middleware_stack: Vec<Arc<dyn Middleware>>,
diff --git a/reqwest-middleware/src/middleware.rs b/reqwest-middleware/src/middleware.rs
index acf94da..26e022f 100644
--- a/reqwest-middleware/src/middleware.rs
+++ b/reqwest-middleware/src/middleware.rs
@@ -47,6 +47,12 @@ pub trait Middleware: 'static + Send + Sync {
     ) -> Result<Response>;
 }
 
+impl std::fmt::Debug for dyn Middleware {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "Middleware")
+    }
+}
+
 #[cfg_attr(not(target_arch = "wasm32"), async_trait::async_trait)]
 #[cfg_attr(target_arch = "wasm32", async_trait::async_trait(?Send))]
 impl<F> Middleware for F
diff --git a/reqwest-middleware/src/req_init.rs b/reqwest-middleware/src/req_init.rs
index 92c8167..8e42172 100644
--- a/reqwest-middleware/src/req_init.rs
+++ b/reqwest-middleware/src/req_init.rs
@@ -23,6 +23,12 @@ pub trait RequestInitialiser: 'static + Send + Sync {
     fn init(&self, req: RequestBuilder) -> RequestBuilder;
 }
 
+impl core::fmt::Debug for dyn RequestInitialiser {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "RequestInitialiser")
+    }
+}
+
 impl<F> RequestInitialiser for F
 where
     F: Send + Sync + 'static + Fn(RequestBuilder) -> RequestBuilder,