diff --git a/app/models/activity_pub/activity.rb b/app/models/activity_pub/activity.rb
index ee555474..af005ff3 100644
--- a/app/models/activity_pub/activity.rb
+++ b/app/models/activity_pub/activity.rb
@@ -21,7 +21,7 @@ class ActivityPub
 
     validates :activity_pub_id, presence: true
     # Las actividades son únicas con respecto a su estado
-    validates :uri, presence: true, uniqueness: { scope: :activity_pub_id, message: 'estado duplicado' }
+    validates :uri, presence: true, url: true, uniqueness: { scope: :activity_pub_id, message: 'estado duplicado' }
 
     # Siempre en orden descendiente para saber el último estado
     default_scope -> { order(created_at: :desc) }
diff --git a/app/models/activity_pub/actor.rb b/app/models/activity_pub/actor.rb
index 919bc5e0..b03145e7 100644
--- a/app/models/activity_pub/actor.rb
+++ b/app/models/activity_pub/actor.rb
@@ -16,7 +16,7 @@ class ActivityPub
     has_many :remote_flags
 
     # Les actores son únicxs a toda la base de datos
-    validates :uri, presence: true, uniqueness: true
+    validates :uri, presence: true, url: true, uniqueness: true
 
     # Obtiene el nombre de la Actor como mención, solo si obtuvimos el
     # contenido de antemano.
diff --git a/app/models/activity_pub/object.rb b/app/models/activity_pub/object.rb
index 15b07bee..3fde326b 100644
--- a/app/models/activity_pub/object.rb
+++ b/app/models/activity_pub/object.rb
@@ -6,7 +6,7 @@ class ActivityPub
     include ActivityPub::Concerns::JsonLdConcern
 
     # Los objetos son únicos a toda la base de datos
-    validates :uri, presence: true, uniqueness: true
+    validates :uri, presence: true, url: true, uniqueness: true
 
     has_many :activity_pubs, as: :object
 
diff --git a/app/validators/url_validator.rb b/app/validators/url_validator.rb
new file mode 100644
index 00000000..291f9288
--- /dev/null
+++ b/app/validators/url_validator.rb
@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+# Valida URLs
+#
+# @see {https://storck.io/posts/better-http-url-validation-in-ruby-on-rails/}
+class UrlValidator < ActiveModel::EachValidator
+  def validate_each(record, attribute, value)
+    if value.blank?
+      record.errors.add(attribute, :url_missing)
+      return
+    end
+
+    uri = URI.parse(value)
+
+    record.errors.add(attribute, :scheme_missing) if uri.scheme.blank?
+    record.errors.add(attribute, :host_missing) if uri.host.blank?
+    record.errors.add(attribute, :path_missing) if uri.path.blank?
+  rescue URI::Error
+    record.errors.add(attribute, :invalid)
+  end
+end