diff --git a/Cargo.lock b/Cargo.lock
index b8eb97d..6c1d6ad 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -671,6 +671,7 @@ dependencies = [
  "open 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rayon 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "send-cell 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "url 1.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
diff --git a/hammond-data/src/lib.rs b/hammond-data/src/lib.rs
index 7e2de25..f498821 100644
--- a/hammond-data/src/lib.rs
+++ b/hammond-data/src/lib.rs
@@ -1,14 +1,13 @@
 #![recursion_limit = "1024"]
+#![cfg_attr(all(test, feature = "clippy"), allow(option_unwrap_used, result_unwrap_used))]
 #![cfg_attr(feature = "cargo-clippy", allow(blacklisted_name))]
 #![cfg_attr(feature = "clippy",
             warn(option_unwrap_used, result_unwrap_used, print_stdout,
                  wrong_pub_self_convention, mut_mut, non_ascii_literal, similar_names,
                  unicode_not_nfc, enum_glob_use, if_not_else, items_after_statements,
                  used_underscore_binding))]
-#![cfg_attr(all(test, feature = "clippy"), allow(option_unwrap_used, result_unwrap_used))]
 
-//! A libraty for parsing, indexing and retrieving podcast Feeds,
-//! into and from a Database.
+//! FIXME: Docs
 
 #![allow(unknown_lints)]
 #![deny(bad_style, const_err, dead_code, improper_ctypes, legacy_directory_ownership,
@@ -19,7 +18,6 @@
         unused_parens, while_true)]
 #![deny(missing_debug_implementations, missing_docs, trivial_casts, trivial_numeric_casts)]
 #![deny(unused_extern_crates, unused)]
-#![deny(unused_extern_crates, unused)]
 
 // #![feature(conservative_impl_trait)]
 
diff --git a/hammond-data/src/utils.rs b/hammond-data/src/utils.rs
index 18a38b5..4ecb386 100644
--- a/hammond-data/src/utils.rs
+++ b/hammond-data/src/utils.rs
@@ -16,12 +16,12 @@ use std::path::Path;
 
 /// Scan downloaded `episode` entries that might have broken `local_uri`s and set them to `None`.
 fn download_checker() -> Result<()> {
-    let episodes = dbqueries::get_downloaded_episodes()?;
+    let mut episodes = dbqueries::get_downloaded_episodes()?;
 
     episodes
-        .into_par_iter()
+        .par_iter_mut()
         .filter(|ep| !Path::new(ep.local_uri().unwrap()).exists())
-        .for_each(|mut ep| {
+        .for_each(|ep| {
             ep.set_local_uri(None);
             if let Err(err) = ep.save() {
                 error!("Error while trying to update episode: {:#?}", ep);
diff --git a/hammond-gtk/Cargo.toml b/hammond-gtk/Cargo.toml
index 31047ad..e1c8c49 100644
--- a/hammond-gtk/Cargo.toml
+++ b/hammond-gtk/Cargo.toml
@@ -19,6 +19,7 @@ loggerv = "0.7.0"
 open = "1.2.1"
 rayon = "0.9.0"
 send-cell = "0.1.2"
+url = "1.6.0"
 
 [dependencies.gtk]
 features = ["v3_22"]
diff --git a/hammond-gtk/resources/gtk/headerbar.ui b/hammond-gtk/resources/gtk/headerbar.ui
index e728022..9152d75 100644
--- a/hammond-gtk/resources/gtk/headerbar.ui
+++ b/hammond-gtk/resources/gtk/headerbar.ui
@@ -129,7 +129,7 @@ Tobias Bernard
           </packing>
         </child>
         <child>
-          <object class="GtkLabel" id="already_subscribed_label">
+          <object class="GtkLabel" id="result_label">
             <property name="can_focus">False</property>
             <property name="halign">start</property>
             <property name="label" translatable="yes">You are already subscribed to that feed!</property>
diff --git a/hammond-gtk/src/headerbar.rs b/hammond-gtk/src/headerbar.rs
index 3f36f80..3babee7 100644
--- a/hammond-gtk/src/headerbar.rs
+++ b/hammond-gtk/src/headerbar.rs
@@ -2,6 +2,7 @@ use gtk;
 use gtk::prelude::*;
 
 use hammond_data::Source;
+use url::Url;
 
 use std::sync::Arc;
 use std::sync::mpsc::Sender;
@@ -63,11 +64,12 @@ impl Header {
         let add_popover: gtk::Popover = builder.get_object("add_popover").unwrap();
         let new_url: gtk::Entry = builder.get_object("new_url").unwrap();
         let add_button: gtk::Button = builder.get_object("add_button").unwrap();
+        let result_label: gtk::Label = builder.get_object("result_label").unwrap();
         self.switch.set_stack(&content.get_stack());
 
-        new_url.connect_changed(move |url| {
-            println!("{:?}", url.get_text());
-        });
+        new_url.connect_changed(clone!(add_button => move |url| {
+            on_url_change(url, &result_label, &add_button);
+        }));
 
         add_button.connect_clicked(clone!(add_popover, new_url, sender => move |_| {
             on_add_bttn_clicked(&new_url, sender.clone());
@@ -139,3 +141,24 @@ fn on_add_bttn_clicked(entry: &gtk::Entry, sender: Sender<Action>) {
         error!("Error: {:?}", source.unwrap_err());
     }
 }
+
+fn on_url_change(entry: &gtk::Entry, result: &gtk::Label, add_button: &gtk::Button) {
+    let uri = entry.get_text().unwrap();
+    debug!("Url: {}", uri);
+
+    let url = Url::parse(&uri);
+    match url {
+        // TODO: Check if the url exists
+        Ok(_u) => {
+            add_button.set_sensitive(true);
+            result.hide();
+        }
+        // TODO: refactor to avoid duplication
+        Err(err) => {
+            add_button.set_sensitive(false);
+            result.set_label("Invalid url.");
+            result.show();
+            error!("Error: {}", err);
+        }
+    }
+}
diff --git a/hammond-gtk/src/main.rs b/hammond-gtk/src/main.rs
index 5c9f969..b36e2ef 100644
--- a/hammond-gtk/src/main.rs
+++ b/hammond-gtk/src/main.rs
@@ -19,6 +19,7 @@ extern crate log;
 extern crate loggerv;
 extern crate open;
 extern crate send_cell;
+extern crate url;
 // extern crate rayon;
 
 // use rayon::prelude::*;