diff --git a/pagetop/src/core/module/all.rs b/pagetop/src/core/module/all.rs
index 2e499f23..e902c1ec 100644
--- a/pagetop/src/core/module/all.rs
+++ b/pagetop/src/core/module/all.rs
@@ -1,14 +1,20 @@
 use crate::{Lazy, app, run_now, trace};
 use crate::db::*;
-use super::ModuleTrait;
+use super::{ExtensionTrait, ModuleTrait};
 
-use std::sync::RwLock;
+use std::sync::{Arc, RwLock};
+use std::collections::HashMap;
 
 // Módulos registrados.
 static MODULES: Lazy<RwLock<Vec<&dyn ModuleTrait>>> = Lazy::new(|| {
     RwLock::new(Vec::new())
 });
 
+// Extensiones registradas.
+static EXTENSIONS: Lazy<RwLock<HashMap<&str, Arc<Vec<&dyn ExtensionTrait>>>>> = Lazy::new(|| {
+    RwLock::new(HashMap::new())
+});
+
 pub fn register_module(module: &'static dyn ModuleTrait) {
     let mut list: Vec<&dyn ModuleTrait> = Vec::new();
     add_to(&mut list, module);
@@ -17,11 +23,24 @@ pub fn register_module(module: &'static dyn ModuleTrait) {
 }
 
 fn add_to(list: &mut Vec<&dyn ModuleTrait>, module: &'static dyn ModuleTrait) {
-    if !MODULES.read().unwrap().iter().any(|m| m.name() == module.name()) {
-        if !list.iter().any(|m| m.name() == module.name()) {
+    if !MODULES.read().unwrap().iter().any(|m| m.type_name() == module.type_name()) {
+        if !list.iter().any(|m| m.type_name() == module.type_name()) {
             trace::debug!("Registering \"{}\" module", module.single_name());
             list.push(module);
 
+
+            let mut hmap = EXTENSIONS.write().unwrap();
+            for e in module.extensions().iter() {
+                if let Some(extensions) = hmap.get_mut(e.type_name()) {
+                    let v = Arc::get_mut(extensions).unwrap();
+                    v.push(*e);
+                    v.sort_by_key(|e| e.weight());
+                } else {
+                    hmap.insert(e.type_name(), Arc::new(vec![*e]));
+                }
+            }
+
+
             let mut dependencies = module.dependencies();
             dependencies.reverse();
             for d in dependencies.iter() {
@@ -37,6 +56,13 @@ pub fn modules(cfg: &mut app::web::ServiceConfig) {
     }
 }
 
+pub fn extensions(type_name: &'static str) -> Option<Arc<Vec<&dyn ExtensionTrait>>> {
+    match EXTENSIONS.read().unwrap().get(type_name) {
+        Some(extensions) => Some(extensions.clone()),
+        _ => None,
+    }
+}
+
 #[cfg(any(feature = "mysql", feature = "postgres", feature = "sqlite"))]
 pub fn migrations() {
     run_now({
diff --git a/pagetop/src/core/module/definition.rs b/pagetop/src/core/module/definition.rs
index baaadd98..58a8d4ea 100644
--- a/pagetop/src/core/module/definition.rs
+++ b/pagetop/src/core/module/definition.rs
@@ -1,15 +1,16 @@
-use crate::app;
-use crate::util::partial_type_name;
+use crate::{app, util};
 
 #[cfg(any(feature = "mysql", feature = "postgres", feature = "sqlite"))]
 use crate::db;
 
+use super::ExtensionTrait;
+
 pub trait BaseModule {
     fn type_name(&self) -> &'static str;
 
     fn single_name(&self) -> &'static str;
 
-    fn qualified_name(&self, last: usize) -> &'static str;
+    fn qualified_name(&self, last: u8) -> &'static str;
 }
 
 /// Los módulos deben implementar este *trait*.
@@ -22,19 +23,23 @@ pub trait ModuleTrait: BaseModule + Send + Sync {
         None
     }
 
-    fn dependencies(&self) -> Vec<&'static dyn ModuleTrait> {
-        vec![]
-    }
-
     #[allow(unused_variables)]
     fn configure_module(&self, cfg: &mut app::web::ServiceConfig) {
     }
 
+    fn extensions(&self) -> Vec<&'static dyn ExtensionTrait> {
+        vec![]
+    }
+
     #[cfg(any(feature = "mysql", feature = "postgres", feature = "sqlite"))]
     #[allow(unused_variables)]
     fn migrations(&self) -> Vec<Box<dyn db::MigrationTrait>> {
         vec![]
     }
+
+    fn dependencies(&self) -> Vec<&'static dyn ModuleTrait> {
+        vec![]
+    }
 }
 
 impl<M: ?Sized + ModuleTrait> BaseModule for M {
@@ -43,10 +48,10 @@ impl<M: ?Sized + ModuleTrait> BaseModule for M {
     }
 
     fn single_name(&self) -> &'static str {
-        partial_type_name(std::any::type_name::<Self>(), 1)
+        util::partial_type_name(std::any::type_name::<Self>(), 1)
     }
 
-    fn qualified_name(&self, last: usize) -> &'static str {
-        partial_type_name(std::any::type_name::<Self>(), last)
+    fn qualified_name(&self, last: u8) -> &'static str {
+        util::partial_type_name(std::any::type_name::<Self>(), last)
     }
 }
diff --git a/pagetop/src/core/module/extension.rs b/pagetop/src/core/module/extension.rs
new file mode 100644
index 00000000..e8b8107c
--- /dev/null
+++ b/pagetop/src/core/module/extension.rs
@@ -0,0 +1,30 @@
+use crate::util;
+
+pub trait BaseExtension {
+    fn type_name(&self) -> &'static str;
+
+    fn single_name(&self) -> &'static str;
+
+    fn qualified_name(&self, last: u8) -> &'static str;
+}
+
+/// Las extensiones deben extender este *trait*.
+pub trait ExtensionTrait: BaseExtension + Send + Sync {
+    fn weight(&self) -> i8 {
+        0
+    }
+}
+
+impl<E: ?Sized + ExtensionTrait> BaseExtension for E {
+    fn type_name(&self) -> &'static str {
+        std::any::type_name::<Self>()
+    }
+
+    fn single_name(&self) -> &'static str {
+        util::partial_type_name(std::any::type_name::<Self>(), 1)
+    }
+
+    fn qualified_name(&self, last: u8) -> &'static str {
+        util::partial_type_name(std::any::type_name::<Self>(), last)
+    }
+}
diff --git a/pagetop/src/core/module/mod.rs b/pagetop/src/core/module/mod.rs
index 720d806c..d72bd48d 100644
--- a/pagetop/src/core/module/mod.rs
+++ b/pagetop/src/core/module/mod.rs
@@ -3,6 +3,14 @@ pub use definition::{
     BaseModule,
     ModuleTrait,
 };
+mod extension;
+pub use extension::{
+    BaseExtension,
+    ExtensionTrait,
+};
 
 pub(crate) mod all;
-pub use all::register_module;
\ No newline at end of file
+pub use all::{
+    extensions,
+    register_module
+};
diff --git a/pagetop/src/core/response/page/component.rs b/pagetop/src/core/response/page/component.rs
index aa1160b1..0bbc3abf 100644
--- a/pagetop/src/core/response/page/component.rs
+++ b/pagetop/src/core/response/page/component.rs
@@ -1,6 +1,6 @@
 use crate::html::{Markup, html};
 use crate::core::response::page::PageAssets;
-use crate::util::partial_type_name;
+use crate::util;
 
 pub use std::any::Any as AnyComponent;
 
@@ -9,7 +9,7 @@ pub trait BaseComponent {
 
     fn single_name(&self) -> &'static str;
 
-    fn qualified_name(&self, last: usize) -> &'static str;
+    fn qualified_name(&self, last: u8) -> &'static str;
 }
 
 pub trait ComponentTrait: AnyComponent + BaseComponent + Send + Sync {
@@ -52,11 +52,11 @@ impl<C: ?Sized + ComponentTrait> BaseComponent for C {
     }
 
     fn single_name(&self) -> &'static str {
-        partial_type_name(std::any::type_name::<Self>(), 1)
+        util::partial_type_name(std::any::type_name::<Self>(), 1)
     }
 
-    fn qualified_name(&self, last: usize) -> &'static str {
-        partial_type_name(std::any::type_name::<Self>(), last)
+    fn qualified_name(&self, last: u8) -> &'static str {
+        util::partial_type_name(std::any::type_name::<Self>(), last)
     }
 }
 
diff --git a/pagetop/src/core/theme/definition.rs b/pagetop/src/core/theme/definition.rs
index 1d6df035..130dfdac 100644
--- a/pagetop/src/core/theme/definition.rs
+++ b/pagetop/src/core/theme/definition.rs
@@ -3,14 +3,14 @@ use crate::config::SETTINGS;
 use crate::html::{Markup, html};
 use crate::core::response::page::{ComponentTrait, Favicon, Page, PageAssets};
 use crate::base::component::Chunck;
-use crate::util::partial_type_name;
+use crate::util;
 
 pub trait BaseTheme {
     fn type_name(&self) -> &'static str;
 
     fn single_name(&self) -> &'static str;
 
-    fn qualified_name(&self, last: usize) -> &'static str;
+    fn qualified_name(&self, last: u8) -> &'static str;
 }
 
 /// Los temas deben implementar este "trait".
@@ -143,10 +143,10 @@ impl<T: ?Sized + ThemeTrait> BaseTheme for T {
     }
 
     fn single_name(&self) -> &'static str {
-        partial_type_name(std::any::type_name::<Self>(), 1)
+        util::partial_type_name(std::any::type_name::<Self>(), 1)
     }
 
-    fn qualified_name(&self, last: usize) -> &'static str {
-        partial_type_name(std::any::type_name::<Self>(), last)
+    fn qualified_name(&self, last: u8) -> &'static str {
+        util::partial_type_name(std::any::type_name::<Self>(), last)
     }
 }
diff --git a/pagetop/src/util.rs b/pagetop/src/util.rs
index ca4a96fc..3190b641 100644
--- a/pagetop/src/util.rs
+++ b/pagetop/src/util.rs
@@ -47,11 +47,12 @@ macro_rules! theme_static_files {
     }};
 }
 
-pub(crate) fn partial_type_name(type_name: &'static str, last: usize) -> &'static str {
+pub(crate) fn partial_type_name(type_name: &'static str, last: u8) -> &'static str {
     if last == 0 {
         return type_name;
     }
     let positions: Vec<_> = type_name.rmatch_indices("::").collect();
+    let last: usize = last as usize;
     if positions.len() < last {
         return type_name;
     }