diff --git a/proxmox-api/src/const_regex.rs b/proxmox-api/src/const_regex.rs
index 320a914b..9bcedbea 100644
--- a/proxmox-api/src/const_regex.rs
+++ b/proxmox-api/src/const_regex.rs
@@ -1,3 +1,9 @@
+//! Allow to build Regex within `const_fn`
+//!
+//! The current Regex::new() function is not `const_fn`. Unless that
+//! works, we use a macro to generate something we can use inside
+//! `const_fn`.
+
 /// Macro to generate a ConstRegexPattern
 #[macro_export]
 macro_rules! const_regex {
diff --git a/proxmox-api/src/error.rs b/proxmox-api/src/error.rs
index d6fb4738..5385325d 100644
--- a/proxmox-api/src/error.rs
+++ b/proxmox-api/src/error.rs
@@ -5,6 +5,7 @@ use failure::Fail;
 #[doc(hidden)]
 pub use hyper::StatusCode;
 
+/// HTTP error including `StatusCode` and message.
 #[derive(Debug, Fail)]
 pub struct HttpError {
     pub code: StatusCode,
@@ -23,6 +24,7 @@ impl fmt::Display for HttpError {
     }
 }
 
+/// Macro to create a HttpError inside a failure::Error
 #[macro_export]
 macro_rules! http_err {
     ($status:ident, $msg:expr) => {{
diff --git a/proxmox-api/src/lib.rs b/proxmox-api/src/lib.rs
index 6cb8bc6a..98bc5328 100644
--- a/proxmox-api/src/lib.rs
+++ b/proxmox-api/src/lib.rs
@@ -10,9 +10,12 @@ use hyper::{Body, Response};
 use serde_json::Value;
 
 pub mod const_regex;
+#[doc(hidden)]
 pub mod error;
 pub mod format;
+#[doc(hidden)]
 pub mod router;
+#[doc(hidden)]
 pub mod rpc_environment;
 pub mod schema;