diff --git a/lib/noosfero/api/api.rb b/lib/noosfero/api/api.rb
index 86eb4a0..4966f0b 100644
--- a/lib/noosfero/api/api.rb
+++ b/lib/noosfero/api/api.rb
@@ -6,6 +6,7 @@ module Noosfero
   module API
 
     class NoosferoFederation < Grape::API
+      helpers APIHelpers
       before { detect_stuff_by_domain }
       format :json
       content_type :json, "application/jrd+json"
diff --git a/lib/noosfero/api/federation/webfinger.rb b/lib/noosfero/api/federation/webfinger.rb
index 01b1a87..8dc4bd0 100644
--- a/lib/noosfero/api/federation/webfinger.rb
+++ b/lib/noosfero/api/federation/webfinger.rb
@@ -3,9 +3,9 @@ module Noosfero
   module API
     module Federation
       class Webfinger < Grape::API
-        get "webfinger" do
+        get 'webfinger' do
           result = generate_jrd
-          present result, :with => Grape::Presenters::Presenter
+          present result, with: Grape::Presenters::Presenter
         end
       end
     end
@@ -13,62 +13,79 @@ module Noosfero
 end
 
 def generate_jrd
-  result = {}
-  if valid_domain? && request_acct?
-    result = acct_hash
-  elsif valid_domain? && valid_uri?(params[:resource])
-    result = uri_hash
+  unless valid_domain?
+    not_found!
+    Rails.logger.error 'Domain Not Found'
+  end
+  if request_acct?
+    acct_hash
+  elsif valid_uri?(params[:resource])
+    uri_hash
   end
 end
 
-def valid_domain?
-  #validate domain if resource have acct
+def domain
   if request_acct?
-    domain  = params[:resource].split("@")[1]
-    environment.domains.map(&:name).include? domain
+    params[:resource].split('@')[1]
   else
-    domain  = params[:resource].split("/")[2]
-    environment.domains.map(&:name).include? domain
+    params[:resource].split('/')[2]
   end
 end
 
+def valid_domain?
+  environment.domains.map(&:name).include? domain
+end
+
 def request_acct?
-  params[:resource].include? "acct:"
+  params[:resource].include? 'acct:'
 end
 
 def acct_hash
   acct = {}
   acct[:subject] = params[:resource]
   acct[:properties] = Person.find_by_identifier(extract_person_identifier)
+  if acct[:properties].nil?
+    Rails.logger.error 'Person not found'
+    not_found!
+  end
   acct
 end
 
 def extract_person_identifier
-  params[:resource].split("@")[0].split(":")[1]
+  params[:resource].split('@')[0].split(':')[1]
 end
 
 def valid_uri?(url)
   uri = URI.parse(url)
-  uri.kind_of?(URI::HTTP)
-  rescue URI::BadURIError => ex
-    Rails.logger.error "Bad URI Error: #{ex}"
-  rescue URI::InvalidURIError => ex
-    Rails.logger.error "Invalid URI Error: #{ex}"
+  if uri.is_a?(URI::HTTP)
+    true
+  else
+    Rails.logger.error 'Bad URI Error'
+    not_found!
+  end
 end
 
 def uri_hash
   uri = {}
   uri[:subject] = params[:resource]
-  entity = entity_exists?(params[:resource])
+  entity = find_entity(params[:resource])
   id = params[:resource].split('/').last.to_i
-  uri[:properties] = entity.classify.constantize.find(id)
+  begin
+    uri[:properties] = entity.classify.constantize.find(id)
+  rescue ActiveRecord::RecordNotFound
+    Rails.logger.error "Entity: #{entity} with id: #{id} not found"
+    not_found!
+  end
   uri
 end
 
-def entity_exists?(uri)
+def find_entity(uri)
   possible_entity = uri.split('/')
-  possible_entity.map! {|entity| "#{entity}s"}
-  ( ActiveRecord::Base.connection.tables & possible_entity ).first
-  rescue ActiveRecord::RecordNotFound => ex
-    Rails.logger.error "Entity not found on records: #{ex}"
+  possible_entity.map! { |entity| "#{entity}s" }
+  entity = (ActiveRecord::Base.connection.tables & possible_entity).first
+  unless entity
+    Rails.logger.error 'Entity not found on records'
+    not_found!
+  end
+  entity
 end
diff --git a/test/api/federation/webfinger_test.rb b/test/api/federation/webfinger_test.rb
index e24c56b..f6e3784 100644
--- a/test/api/federation/webfinger_test.rb
+++ b/test/api/federation/webfinger_test.rb
@@ -1,8 +1,9 @@
 require_relative '../test_helper'
 
 class WebfingerTest < ActiveSupport::TestCase
-
   def setup
+    Domain.create(name: 'example.com')
+    Environment.default.domains << Domain.last
     login_api
   end
 
@@ -13,10 +14,40 @@ class WebfingerTest < ActiveSupport::TestCase
     assert_equal webfinger['subject'], 'acct:ze@example.com'
   end
 
+  should 'not return json when user not found' do
+    invalid_user = 'invalid_user_in_url'
+    get ".well-known/webfinger?resource=acct%3A#{invalid_user}%40example.com"
+    assert_equal 404, last_response.status
+  end
+
   should 'return correct article via webfinger url' do
-    get '.well-known/webfinger?resource=http://example.com/article/id/1'
+    a = fast_create(Article, name: 'my article', profile_id: 1)
+    a.save
+    get ".well-known/webfinger?resource=http://example.com/article/id/#{a.id}"
     webfinger =  JSON.parse(last_response.body)
     assert_equal 200, last_response.status
-    assert_equal webfinger['subject'], 'http://example.com/article/id/1'
+    assert_equal webfinger['subject'], "http://example.com/article/id/#{a.id}"
+  end
+
+  should 'not return json when domain is invalid' do
+    invalid_domain = 'doest_not_exist.com'
+    get ".well-known/webfinger?resource=http://#{invalid_domain}/article/id/1"
+    assert_equal 404, last_response.status
+  end
+
+  should 'not return json when entity is not found' do
+    get '.well-known/webfinger?resource=http://example.com/article/id/999999'
+    assert_equal 404, last_response.status
+  end
+
+  should 'not return json when entity does not exist' do
+    get '.well-known/webfinger?resource=http://example.com/doest_not_exist/id/1'
+    assert_equal 404, last_response.status
+  end
+
+  should 'not return json when request is not http' do
+    not_http_url = 'kkttc://example.com/article/id/1'
+    get ".well-known/webfinger?resource=#{not_http_url}"
+    assert_equal 404, last_response.status
   end
 end
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